Guideline for the Evaluation and Treatment of Corrosion and Fouling in Fire Protection Systems

EPRI • 3412 Hillview Avenue, Palo Alto, California 94304 • PO Box 10412, Palo Alto, California 94303 • USA800.313.3774 • 650.855.2121 • [email protected] • www.epri.com

Guideline for the Evaluation andTreatment of Corrosion and Foulingin Fire Protection Systems

TR-109633

Final Report, March 1999

EPRI Project ManagerT. Eckert

Effective December 6, 2006, this report has been made publicly available in accordance with Section 734.3(b)(3) and published in accordance with Section 734.7 of the U.S. Export Administration Regulations. As a result of this publication, this report is subject to only copyright protection and does not require any license agreement from EPRI. This notice supersedes the export control restrictions and any proprietary licensed material notices embedded in the document prior to publication

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iii

CITATION

This report was prepared by

R. W. Lutey & Associates6848 Stornaway DriveMemphis, TN 38119

Principal InvestigatorDr. Richard W. Lutey

This report describes research sponsored by EPRI. The report is a corporate documentthat should be cited in the literature in the following manner:

Guidelines for the Evaluation and Treatment of Corrosion and Fouling in Fire ProtectionSystems, EPRI, Palo Alto, CA: 1999. Report TR-109633.

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REPORT SUMMARY

This guideline document addresses the methods to control and mitigate corrosion,fouling, and microbiological growth in water-related fire protection systems (FPSs).

Background

The reliability of fire protection systems (FPSs) is most important to prevention andmitigation of the consequences of fires. FPSs are subject to degradation through varioustypes of fouling and corrosion, which can impact performance and service life.Corrosion degradation can result in material replacements and major maintenancecosts. The causes of corrosion degradation of the FPS have not been studied asextensively and is not as well reported in the literature as other water-filled systems.

Fouling, either associated with microbiological growth or related to sedimentation, canimpact the function of individual components, such as valves and sprinklers, or canresult in the failure of the FPS in the prevention or mitigation of the consequences offires.

Objectives

To provide engineers and chemists with guidance for maintaining optimum systemintegrity and performance in Fire Protection Systems.

Approach

The EPRI Plant Support Engineering Program established the Corrosion and Fouling inFire Protection Systems Task Group, which met five times in 1998. The Task Groupidentified the basic issues concerning wetted fire protection systems, reviewed variousutility fire water corrosion and fouling programs, and compiled the best practices todevelop this document.

Key Points

• Water and foam-water fire protection system designs are described.

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• The capability of these systems to carry out their function is impacted by mechanicallimitations, plugging and fouling, and various forms of corrosion.

• Assessment of the fire protection system’s condition requires comprehensiveinspections, microbiological and chemical surveys, and a complete commitment toroutine preventive maintenance.

• Mitigation treatment programs have generally proven to be more expensive thancontrol treatment programs.

• Monitoring techniques to assess the performance of corrosion and fouling controlmeasures are provided.

• Industry consensus was achieved.

Keywords

Fire protectionCorrosion protectionFoulingMicrobial corrosionChemistry

Interest Categories

Corrosion controlPlant support engineeringService water systemsFire protectionChemistry

EPRI Licensed Material

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ACKNOWLEDGMENTS

The following individuals were ongoing members of Plant Support Engineering'sCorrosion and Fouling in Fire Protection Systems Task Group. As such, they have madesignificant contributions to the development of this guide by attending the majority ofthe task group meetings, reviewing/commenting on various drafts, and writingportions of the document.

David Piller, Utility Chairman PECO NuclearEd Dressler American Nuclear InsurersPaul Giaccaglia American Nuclear InsurersHenry W. Riley Jr. P.E. Arizona Public Service Co.John Carroll Betz Laboratories, Inc.Raymond M. Post Betz Laboratories, Inc.Bennett P. Boffardi Boffardi & AssociatesRichard E. McKee Calgon CorporationChuck Bowman Chuck Bowman AssociatesBill Burke Entergy Services, Inc.Russ Green GPU Nuclear, Inc.Eric Hale Nalco Chemical Co.John Kristensen New York Power AuthorityJeffrey E. Peters Northeast UtilitiesChris Dahms Nuclear Electric Insurance, Ltd.Wayne Sohlman Nuclear Electric Insurance, Ltd.K. Anthony Selby Puckorius & Associates, Inc.Dave Chiang Southern California Edison Co.Mickey Perry Southern Nuclear Operating Co.George J. Licina Structural Integrity Associates, Inc.E. S. Chandrasekaran Tennessee Valley Authority (TVA)Wayne C. Micheletti Wayne C. Micheletti, Inc.


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CONTENTS

1 INTRODUCTION ................................................................................................................. 1-1

1.1 Background - Fire Protection Systems in Power Plants................................................ 1-1

1.2 Purpose ........................................................................................................................ 1-1

1.3 Scope ........................................................................................................................... 1-2

1.4 Assumptions ................................................................................................................. 1-2

1.5 Management Responsibility and Program Ownership .................................................. 1-3

2 DESCRIPTION .................................................................................................................... 2-1

2.1 Purpose of Fire Protection Systems - Service/Performance Requirements .................. 2-1

2.2 Fire Protection System Designs.................................................................................... 2-1

2.2.1 Sprinkler Systems .................................................................................................. 2-1

2.2.1.1 Variations of Sprinkler System Design ............................................................ 2-1

2.2.2 Standpipe Systems ................................................................................................ 2-2

2.2.2.1 Variations in Standpipe System Design .......................................................... 2-3

2.2.3 Water Spray Fixed Systems................................................................................... 2-3

2.2.4 Foam-Water Sprinkler Systems.............................................................................. 2-3

2.2.5 Foam-Water Spray Systems .................................................................................. 2-4

2.3 Fire Protection System Materials of Construction ......................................................... 2-4

2.3.1 Piping ..................................................................................................................... 2-4

2.3.2 Water Supply.......................................................................................................... 2-6

2.3.3 Pumps (Including Jockey Pumps) and Sprinkler Heads......................................... 2-6

2.3.4 Preaction, Deluge, and Fixed Foam Systems ........................................................ 2-6

2.4 System Operation Variations ........................................................................................ 2-7

2.4.1 Operation Procedures ............................................................................................ 2-7

2.4.2 System Inspection.................................................................................................. 2-7

2.4.3 Preventive and Mandatory Maintenance Programs ............................................... 2-7


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2.4.4 Corrective Action.................................................................................................... 2-7

2.4.5 System Testing Programs ...................................................................................... 2-7

2.4.6 Impairment Procedures.......................................................................................... 2-8

2.4.7 Maintenance of Records and Reports.................................................................... 2-8

3 PROBLEMS ........................................................................................................................ 3-1

3.1 Problems Impacting Fire Protection Systems ............................................................... 3-1

3.2 Mechanical/Physical Limitations ................................................................................... 3-1

3.3 Plugging and Fouling .................................................................................................... 3-2

3.2.1 Microbiological Fouling........................................................................................... 3-2

3.3.2 Macrofouling........................................................................................................... 3-2

3.3.3 Sedimentation ........................................................................................................ 3-3

3.3.4 Corrosion Products ................................................................................................ 3-3

3.4 Corrosion ...................................................................................................................... 3-4

3.4.1 MIC ........................................................................................................................ 3-4

3.4.2 Under Deposit Corrosion........................................................................................ 3-5

3.4.3 Crevice Corrosion................................................................................................... 3-6

3.4.4 Galvanic Corrosion................................................................................................. 3-6

3.4.5 Other ...................................................................................................................... 3-8

4 ASSESSMENT .................................................................................................................... 4-1

4.1 Discussion .................................................................................................................... 4-1

4.2 Assessment Procedures ............................................................................................... 4-2

4.2.1 Visual Appearance................................................................................................. 4-4

4.2.2 Microbiological Data............................................................................................... 4-5

4.2.3 Chemical Analysis Data ......................................................................................... 4-5

4.2.4 Physical/Operating Data ........................................................................................ 4-6

4.3 Inspection, Testing, and Maintenance .......................................................................... 4-6

4.4 Training......................................................................................................................... 4-8

5 CONTROL AND MITIGATION............................................................................................. 5-1

5.1 Discussion .................................................................................................................... 5-1

5.2 Determining Treatment Needs to Control Corrosion and Fouling ................................. 5-1

5.2.1 Materials and Design ............................................................................................. 5-2

5.2.2 Makeup Water Quality and Source ........................................................................ 5-2


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5.2.3 Operating Considerations ...................................................................................... 5-3

5.2.4 System Condition ................................................................................................... 5-3

5.2.5 Previous Treatment Programs ............................................................................... 5-3

5.2.6 Compatibility........................................................................................................... 5-4

5.2.7 Impact on Other Plant Systems.............................................................................. 5-5

5.3 Mitigation ...................................................................................................................... 5-5

5.3.1 Physical/Mechanical Cleaning................................................................................ 5-6

5.3.2 Chemical Cleaning Methods .................................................................................. 5-6

5.3.2.1 Fill and Soak Chemical Cleaning for Biofouling............................................... 5-7

5.3.2.2 Shut-Down Circulating Chemical Cleaning...................................................... 5-7

5.3.3 Aggressive and Non-Aggressive Chemical Cleaning ............................................. 5-7

5.3.3.1 Aggressive Chemical Cleaning........................................................................ 5-8

5.3.3.2 Non-Aggressive Cleaning................................................................................ 5-9

5.4 Chemicals Used for Chemical Cleaning...................................................................... 5-10

5.4.1 Aggressive Chemicals.......................................................................................... 5-10

5.4.2 Non-Aggressive Chemicals .................................................................................. 5-13

5.5 Chemicals Used for Corrosion Control........................................................................ 5-14

5.5.1 Ferrous Alloy Corrosion Inhibitors ........................................................................ 5-15

5.5.2 Copper Alloy Corrosion Inhibitors......................................................................... 5-16

5.5.3 Other Inhibitors..................................................................................................... 5-16

5.6 Chemical Used for Micro/Macrobiological Control....................................................... 5-17

5.6.1 Chemical Used as Biocides/Biostats .................................................................... 5-18

5.6.1.1 Oxidizing Chemicals...................................................................................... 5-18

5.6.1.2 Non-Oxidizing Biocides/Biostats.................................................................... 5-21

5.6.2 Non-Toxic Control Chemicals............................................................................... 5-24

5.6.3 Non-Chemical Control Options............................................................................. 5-25

5.7 Fouling Control ........................................................................................................... 5-26

5.7.1 Chemicals Used for Fouling Control..................................................................... 5-27

5.7.2 Non-Chemical Means of Fouling Control.............................................................. 5-27

5.8 Non-Chemical Corrosion Control ................................................................................ 5-28

5.8.1 Non-Chemical Corrosion Control of Tanks and Buried Pipe ................................ 5-28

5.8.1.1 Coatings........................................................................................................ 5-28

5.8.1.2 Cathodic Protection....................................................................................... 5-29

5.8.2 Accumulation of Foreign Materials on Sprinklers ................................................. 5-31


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5.8.3 Dry Piping in Dry Pipe Sprinkler, Deluge, and Preaction Systems ....................... 5-31

5.8.4 Foam-Water Systems........................................................................................... 5-31

5.8.5 Other Non-Chemical Corrosion Control Procedures ............................................ 5-32

5.9 Regulatory and Registration Considerations............................................................... 5-32

6 PERFORMANCE MONITORING......................................................................................... 6-1

6.1 Discussion .................................................................................................................... 6-1

6.2 Corrosion Monitoring Techniques ................................................................................. 6-3

6.2.1 Corrosion Coupons ................................................................................................ 6-3

6.2.2 Test Spool Pipe Segments..................................................................................... 6-4

6.2.3 Electrochemical Techniques .................................................................................. 6-5

6.3 Fouling Monitoring Techniques..................................................................................... 6-5

6.4 Microbiological Growth Monitoring Techniques............................................................. 6-7

6.4.1 Planktonic Microbiological Analysis........................................................................ 6-7

6.4.2 Microbiological Analysis of Sessile Colonization .................................................... 6-8

6.4.3 Tuberculation Analysis ........................................................................................... 6-9

6.5 Other Performance Monitoring Techniques ................................................................ 6-10

6.5.1 Internal Visual Inspection .................................................................................... 6-10

6.5.2 Nondestructive Evaluations.................................................................................. 6-10

6.6 Corrosion or Fouling/Leaks Performance Tabulation.................................................. 6-11

6.7 Chemical Analysis Performance Monitoring Criteria ................................................... 6-11

6.8 Data Trending ............................................................................................................. 6-12

7 REFERENCES .................................................................................................................... 7-1

8 APPENDIX A: MICROBIOLOGICAL SURVEY PROCEDURES ......................................... 8-1

I. Background...................................................................................................................... 8-1

On-Site Visual Examination of Accessible Components ................................................. 8-1

On-Site Microscopic Examination.................................................................................... 8-2

On-Site Microbiological Culture Tests ............................................................................. 8-2

Deposits and Metallurgical Analysis ................................................................................ 8-3

Water Chemistry Analysis ............................................................................................... 8-4

Report of Observations and Results ............................................................................... 8-4

II. Description of Test Procedures....................................................................................... 8-4

Microscope...................................................................................................................... 8-4


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Water Suspension Slide Mount Technique ..................................................................... 8-7

Hanging-Drop Slide Mounts ............................................................................................ 8-8

Staining Procedures...................................................................................................... 8-10

Differential Stains for Endospores................................................................................. 8-12

Dry-Mount Films ............................................................................................................ 8-14

Semi-Permanent Slide Mounts...................................................................................... 8-15

Swab Sampling for Culturing from Deposits and Surfaces............................................ 8-16

Isolation and Characterization of Microflora from Water Samples................................. 8-22

Plate Count Method for the Enumeration of Microorganisms........................................ 8-24

Detection of Sulfate-Reducing Bacteria ........................................................................ 8-28

Microscopic Examination of Microbiological and Non-Microbiological Deposits ............ 8-30

Membrane Filter Technique for Detection and Characterization of Microflora............... 8-31

Procedures for Collecting and Transporting Water Samples......................................... 8-35

Procedures for Obtaining and Transporting Pipe Samples ........................................... 8-35

Resources for Materials Used to Perform a Microbiological Survey of an FPS............. 8-36

9 APPENDIX B: INDUSTRY EXPERIENCES ........................................................................ 9-1

1.1 Fire Protection Raw Water System Corrosion and MIC Problems andEffectiveness of Chemical Treatment Programs ................................................................. 9-1

Piping Description ........................................................................................................... 9-1

Current Maintenance and Surveillance Program............................................................. 9-1

Pipe Replacement History............................................................................................... 9-2

Chemical Treatment Program ......................................................................................... 9-2

Fire Protection Pipe Inspections...................................................................................... 9-2

Results of Fire Protection Pipe Inspection ...................................................................... 9-3

Review of Flow Discharge Tests ................................................................................. 9-3

Visual Pipe Inspections with Strainer Baskets/Valves Removed................................. 9-3

Visual Inspections during Pipe Repair/Replacement................................................... 9-3

Ultrasonic Testing........................................................................................................ 9-3

Recommendations .......................................................................................................... 9-3

Short-Term Actions ..................................................................................................... 9-4

Long-Term Actions...................................................................................................... 9-4

2.1 Corrosion Issues as Related to the Philosophy Of Fire Service System Use.............. 9-16

Executive Summary ...................................................................................................... 9-16


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3.1 MIC Tracking Software ............................................................................................... 9-20

4.1 Palo Verde Nuclear Generating Station Fire Protection System Corrosion andFouling Treatment............................................................................................................. 9-21

4.2 Executive Summary .................................................................................................... 9-21

4.3 Introduction of PVNGS Fire Protection Water System................................................ 9-22

4.4 Problems Impacting the PVNGS Fire Protection Water System ................................. 9-24

4.5 System Evaluation and Assessment........................................................................... 9-26

4.6 PVNGS Fire Protection Water System Control and Mitigation .................................... 9-28

4.7 Performance Monitoring and System Enhancements ................................................. 9-31

10 APPENDIX C: GLOSSARY............................................................................................. 10-1

11 APPENDIX D: BIBLIOGRAPHY...................................................................................... 11-1

Reference Books and Manuals......................................................................................... 11-1

Information Industry Surveys ............................................................................................ 11-2

MIC - Microbiology ............................................................................................................ 11-2

MIC - Detection................................................................................................................. 11-3

MIC - Control and Mitigation ............................................................................................. 11-3

MIC - Case Histories......................................................................................................... 11-5

Macrofouling ..................................................................................................................... 11-6

FPS - Design and Materials .............................................................................................. 11-6

FPS - Inspection, Testing, Maintenance ........................................................................... 11-7


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LIST OF FIGURES

Figure 9-1 HPFP Main Headers Inside the Plant (Wet System).............................................. 9-6

Figure 9-2 Proposed Potable Water HPFP System .............................................................. 9-16

Figure 9-3 Discharge Piping Downstream of Valve FS-P-2 .................................................. 9-18

Figure 9-4 Elbow Removed from Dead Leg.......................................................................... 9-19

Figure 9-5 Piping Removed from Dead Leg.......................................................................... 9-19


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LIST OF TABLES

Table 2-1 Materials of Construction ........................................................................................ 2-5

Table 4-1 Fire Water System Assessment Form .................................................................... 4-3

Table 5-1 Chemical Names and Abbreviations..................................................................... 5-11

Table 5-2 Mineral Deposits vs. Solvents............................................................................... 5-11

Table 5-3 Materials vs. Solvents - Compatibility ................................................................... 5-12

Table 5-4 Temperature Limitations ....................................................................................... 5-13

Table 5-5 Inhibitors Used for Corrosion Control with Ferrous Alloys..................................... 5-15

Table 5-6 Oxidizing Chemicals for Microbiological Control ................................................... 5-18

Table 5-7 Non-Oxidizing Biocides......................................................................................... 5-19

Table 5-8 Chemicals for Macrobiological Control.................................................................. 5-20

Table 5-9 Cathodic Protection Criteria for Buried Pipe ......................................................... 5-30

Table 8-1 Optical Specifications ............................................................................................. 8-5

Table 9-1 Pipe Replacement Recommendations.................................................................... 9-7

Table 9-2 Fire Protection Pipe Replacement Cost Estimate ................................................... 9-9

Table 9-3 Unit Rate for Pipe Replacement ........................................................................... 9-11

Table 9-4 Options for Pipe Replacement.............................................................................. 9-12

Table 9-5 Cost Benefit Analysis: 20-Year Remaining Plant Life (1998 Dollars).................... 9-13

Table 9-6 Cost Benefit Analysis: 30-Year Remaining Plant Life (1998 Dollars).................... 9-14

Table 9-7 Replace Piping On An As-Needed Basis.............................................................. 9-15

Table 9-8 PVNGS Well Water Analysis - Fire Protection System ......................................... 9-25

Table 9-9 Typical PVNGS Water Sample and Corrosion Coupon Analysis .......................... 9-30


1-1

1 INTRODUCTION

1.1 Background - Fire Protection Systems in Power Plants

This document addresses the methods to control and mitigate corrosion, fouling, andmicrobiological growth in water-related fire protection systems (FPSs).

The reliability of FPSs is most important in preventing and mitigating the consequencesof fires. FPSs are subject to degradation through various types of fouling and corrosion,which can impact performance and service life. Corrosion degradation can result inmaterial replacements and major maintenance costs. The causes of corrosiondegradation of FPSs have not been studied as extensively and are not as well reportedin the literature as other water-filled systems.

Fouling, either associated with microbiological growth or related to sedimentation, canimpact the function of individual components such as valves and sprinklers, or canresult in the failure of the FPS in preventing and mitigating the consequences of fires.

1.2 Purpose

The purpose of this document is to provide FPS engineers and chemists with guidancefor maintaining optimum FPS integrity and performance . The guidance hereaddresses:

• Establishing site-specific programs

• Understanding the technological basis for treatment programs

• Establishing monitoring methods and frequencies

• Outlining troubleshooting approaches and corrective actions

• Being aware of environmental concerns

• Providing industry experience


Introduction

1-2

While this guideline provides a great deal of technical information on chemicaltreatment of FPSs, it might not eliminate the need for obtaining expert third-partyassistance.

This guideline was developed for nuclear power plants; however, most of theinformation in the document is also applicable to fossil-fueled power plants. They alsohave FPSs that are similar in design and have many of the same problems.

1.3 Scope

The scope of this report is to:

• Describe system design of FPSs

• Provide appropriate definitions

• Describe water-related problems in FPSs

• Provide a detailed guide to chemical selection

• Provide guidance on monitoring a total water treatment program

• Provide guidance on evaluating performance

• Provide a discussion on nonchemical control methods of corrosion and fouling

This document provides a resource for establishing and maintaining a comprehensiveguideline to deal with corrosion and fouling in water-based FPSs. Sufficient detail isprovided to enable the creation of a comprehensive program or the enhancement of anexisting program.

While the methods and technologies described here are extensive, they are not all-inclusive. There are existing methods not described in this document and othermethods are being developed that could be applicable.

1.4 Assumptions

The systems discussed in this guideline are limited to FPSs that are at some point intime associated with water. The guideline does not address steam surface condensercirculating water systems, or “open” or “raw water” cooling water systems, althoughthe treatment programs might be the same or similar.


Introduction

1-3

It is understood that all corrosion is electrochemical in nature. In this document, theterm “electrochemical corrosion” is used to describe corrosion with no microbiologicalinvolvement. Microbiologically influenced corrosion (MIC) is used to describecorrosion where microorganisms are involved.

1.5 Management Responsibility and Program Ownership

It is recognized that a specific program applicable to all plants cannot be defined due todifferences in design, experience, management structure, and operating philosophy.However, the goal is to minimize corrosion and fouling and to maximize theavailability and operating life of FPSs. To meet this goal, an effective control program isessential and should be based upon the following:

• Clear management support for adequate resources, staff, equipment funding, andorganization designed to maintain system integrity

• Recognition of the long-term benefits of, and need for, proper control to avoid orminimize corrosion degradation of major components

• Continuing review of plant and industry experience, research, and revisions to theprogram as appropriate


2-1

2 DESCRIPTION

2.1 Purpose of Fire Protection Systems - Service/Performance Requirements

The purpose of all fire protection systems, regardless of system design, is to provide theperpetual capability of controlling a fire that could disable or destroy individualcomponents or an entire area requiring protection. The performance requirements,without exception, must be done in a rapid, complete, and safe manner under worst-case scenario conditions. Water-based systems are used when the fire resulting fromthe combustion of local materials can be extinguished by water or foam-water withinthe specifications of these performance requirements. The types of system designdiscussed include, but are not limited to, sprinkler, standpipe and hose, fixed waterspray, and foam-water systems.

2.2 Fire Protection System Designs

2.2.1 Sprinkler Systems

A sprinkler system for fire protection purposes is an integrated system of undergroundand overhead piping including sprinklers and one or more automatic water supplies.The portion of the sprinkler system above ground is a network of piping that isinstalled in the area requiring protection, usually overhead and to which sprinklers areattached in a systematic pattern. The valves controlling each system riser are located inthe system riser or its supply piping. Each sprinkler system riser includes a device foractuating an alarm when the system is in operation. The operation of the system isusually activated by heat from a fire and subsequently discharges water over the firearea.

2.2.1.1 Variations of Sprinkler System Design

Wet pipe systems employ automatic sprinklers attached to a piping system containingwater and connected to a water supply so that water discharges immediately fromsprinklers opened by heat from a fire.


Description

2-2

Antifreeze systems employ automatic sprinklers attached to a piping system containingan antifreeze solution and connected to a water supply. The antifreeze solution isdischarged, followed by water, immediately upon operation of the sprinklers openedby heat from a fire.

Dry pipe systems employ automatic sprinklers attached to a piping system containing airor nitrogen under pressure. The release of the pressure, as from the opening of asprinkler, allows the water pressure to open a valve known as a dry pipe valve. Whenthis valve opens, water flows into the piping and out the open sprinklers.

Deluge systems employ open sprinklers attached to a piping system and connected to awater supply through a valve that is opened by the operation of a detection systemlocated in the area to be protected. When this valve opens, water flows into the pipingsystem and discharges in large volumes from all attached sprinklers

Preaction systems employ automatic sprinklers attached to a piping system containingair that might or might not be under pressure. A supplemental detection system thatactuates the supply valve is installed in the same area as the sprinklers. When this valveopens, water flows into the piping system to be discharged from any sprinklers that areopen.

Combined dry pipe-preaction systems employ automatic sprinklers attached to a pipingsystem containing air under pressure, with a supplemental detection system located inthe same area as the sprinklers. Operation of the detection system actuates trippingdevices that open dry pipe valves simultaneously, without a loss of air pressure in thesystem. Operation of the detection system also opens listed air exhaust valves at theend of the feed main, which usually precedes the opening of the sprinklers. Thedetection system also serves as an automatic fire alarm system.

2.2.2 Standpipe Systems

Standpipe systems are designed to provide a source of water for hose connections usedto manually extinguish fires. They consist of an arrangement of piping, valves, hoseconnections, and allied equipment installed at or near the site to be protected. The hoseconnections are located so that water can be discharged in streams or spray patternsthrough the attached hose and nozzles, thus protecting a structure and its occupantsand contents. This is accomplished by connections to water supply systems withmaintained water pressures or to other equipment such as pumps, tanks, and otheritems necessary to provide an adequate volume and water pressure to the hoseconnections. Standpipe systems do not typically employ automatic devices that actuatewater discharge nor do they discharge through a sprinkler system.


Description

2-3

2.2.2.1 Variations in Standpipe System Design

Wet standpipe systems are designed to have the supply valve open and the waterpressure maintained at all times. Water is discharged from the system to the fire bymanual operation of the hose connection valve.

Dry standpipe systems may employ the following options:

• Includes devices to admit water to the system automatically by opening a hosevalve.

• Admits water to the system through manual operation of a remote control devicethat opens valves at each hose station.

• Has no permanent water supply. A filled standpipe having a small water supplyconnection to keep piping filled by requiring water to be pumped into the system isconsidered to be a dry standpipe.

Combined standpipe and sprinkler systems are systems where the water supply pipingservices both 2 ½-in. (63.5-mm) connections for fire department use and outlets forautomatic sprinklers.

2.2.3 Water Spray Fixed Systems

Water spray fixed systems are special fixed piping systems located at specific localizedsites, such as oil storage sites or turbine pumps. These systems are designed to protectindividual components or limited areas. The piping is connected to a reliable watersupply and is equipped with water spray nozzles, rather than sprinklers, for specificwater discharge and distribution over the surface area to be protected. The piping isconnected to the water supply through an automatically or manually actuated valvethat initiates the flow of water. A control valve can be actuated by automatic detectionequipment that is installed in the same area as the spray nozzles.

2.2.4 Foam-Water Sprinkler Systems

Foam-water sprinkler systems consist of piping that is connected to both a source ofliquid foam concentrate and a water supply and are equipped with appropriatedischarge sprinklers that distribute the foam-water over the area to be protected. Thepiping system is connected to the water supply through a control valve that is usuallyactuated by an automatic detection device installed at the site to be protected. Whenthis valve opens, water flows into the piping system and foam concentrate is injectedinto the water. The resulting foam solution flowing through the discharge devicegenerates and distributes the foam. Upon exhaustion of the foam concentrate supply,


Description

2-4

water discharge continues until shut off. Systems are also designed for discharge ofwater first, followed by discharge of foam for a specific period. Existing delugesprinkler systems that have been converted to the use of aqueous film-forming foam areclassified as foam-water sprinkler systems.

2.2.5 Foam-Water Spray Systems

Foam-water spray systems correspond in system design and operations to those for thefoam-water sprinkler systems described in Section 2.2.4, except that discharge isthrough spray systems rather than sprinklers.

2.3 Fire Protection System Materials of Construction

2.3.1 Piping

The materials used for piping depend more on the service requirements than on thetype of system or system design. The size or flow capacities and pipe wall thickness aresystem-specific and also depend on the service requirements of the system. Thecomposition of materials and methods of fabrication of the piping, for example, drawnpipe, seam-welded pipe, seamless pipe, cast pipe, etc., are system-specific and mustmeet appropriate manufacturing standards and specifications. External and internalcoatings are commonly used on piping. These include numerous compositions rangingfrom cement to coal tar epoxy linings and coatings on various metal alloys.

The fabrication/installation standards are dependent on the service requirements of thesystem. These standards include fabrication/installation procedures, such as butt vs.socket field welds; threaded, flanged vs. welded unions and elbows; underground vs.overhead installation. The standards and specifications are discussed extensively inother publications such as those produced by the National Fire Protection Association(NFPA). A number of individual industries including the nuclear/fossil fuel powergenerating industry have their own specific standards and specifications for materialsof construction and fabrication procedures used with fire protection systems.

Taking into account the statements made above concerning standards andspecifications, a broad generalization regarding materials used for piping in fireprotection systems can be made. The wet and dry pipe listed includes headers,standpipes, fixed foam lines, laterals, and branches.


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Table 2-1Materials of Construction

Underground Mains Interior Mains Wet Pipe Dry Pipe

Cement-lined ductile Carbon steel (CS) CS CS

Cement-lined CS Galvanized CS Galvanized CS Galvanized CS

Cement-lined cast iron Black iron

CS specialty-coated

Gray cast iron

Various types of cast iron are widely used in FPSs, especially for buried piping andcertain mechanical parts. Cast iron is an alloy of iron, silica, and carbon. The carbonconcentration is between 1.7–4.5%, most of which is present in insoluble form, (forexample, graphite flakes or nodules). This material is normally called unalloyed castiron and exists in these types:

• Unalloyed gray iron (is soft but still brittle)

• Ductile, malleable cast iron

• Nodular or ductile cast iron (has the most superior mechanical properties andcorrosion resistance)

In addition, there are a number of alloyed cast irons, most of which have improvedcorrosion resistance and substantially modified mechanical and physical propertiessuited for use in buried FPS piping. These include:

• Gray cast iron

• Malleable cast iron

• Ductile or nodular cast iron

• High-silicon cast iron

• Nickel cast iron

Gray cast iron, ductile cast iron, and cement lined ductile and cast iron pipe are thematerials most often used in fire protection underground piping applications.


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2.3.2 Water Supply

Water supply facilities are a part of FPS system design to insure that an adequatesupply of makeup water is available to the fire protection system. The type and volumeof the water storage reservoir is usually system specific. Water storage facilities can beelevated water towers, large ground-level tanks, covered or uncovered man-madereservoirs, or open natural containments of raw surface water. The latter may be ashared water supply to other systems, for example, service water system.

The designated water storage tank found in most systems can be a large welded-platecarbon steel enclosed/covered container. Volumes range from 50,000–500,000 gallons(189–1,893 kiloliters), but can be much smaller or larger depending on the primarysource of the FPS water. Most carbon steel tanks have a corrosion-resistant coatingapplied on the interior surfaces. However, some carbon steel water storage tanks arenot coated. Some carbon steel tanks are equipped with cathodic corrosion protection(CP) devices.

2.3.3 Pumps (Including Jockey Pumps) and Sprinkler Heads

The pumps and sprinkler heads are components that obviously must be in “as-new”condition indefinitely. In wet systems, many of these components are in contact withstagnant water at all times, except during performance testing and inspections. Typicalmaterials of construction of these components include brass or bronze alloys. The bellhousing of the pumps may be cast iron or carbon steel and the pump shafts fabricatedfrom stainless steel. Some parts of the sprinkler heads may be fabricated from austineticstainless steel or chrome-plated steel. It should be noted that materials of constructionand system design in FPSs provide numerous conditions for galvanic couples andsubsequent galvanic corrosion.

2.3.4 Preaction, Deluge, and Fixed Foam Systems

The alternative system designs to wet and dry sprinkler systems and standpipe systemsare included in this category. Materials of construction are often the same. The pipingsystems are those listed earlier. Storage tanks are typically the same design andconstructed with the same materials. The pumps and water delivery systems use thesame materials of construction.


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2.4 System Operation Variations

2.4.1 Operation Procedures

The operation procedures of a specific FPS can vary considerably from one plant toanother. Two systems can look identical but not function or be operated the same.Many of the variations are related to system design. For example, a wet pipe sprinklersystem with a primary water storage tank may be operated differently than onewithout a storage tank. The performance testing would likely be done at a differentfrequency in each situation. The diversion of water from the FPS to other supplementaluses may be more likely with a system that has a storage tank.

2.4.2 System Inspection

System inspection programs vary, both in the schedule for inspections and what is to beinspected. The inspection procedures must meet certain specifications as outlined bythe design standards set for each system. A routine inspection protocol must beestablished and coordinated with all other pertinent system operations.

2.4.3 Preventive and Mandatory Maintenance Programs

Preventive and mandatory maintenance programs vary considerably from system tosystem. The maintenance programs depend to a large extent on the actual physicalcondition of the system, how long the system has been in place, and whether there havebeen substantial system modifications.

2.4.4 Corrective Action

When inspection indicates a need for corrective action, the action to be taken varieswith each FPS.

2.4.5 System Testing Programs

System testing programs vary. The variations depend on the need for specific tests andoften on the availability of testing equipment and testing protocol. Chemical andmicrobiological testing is done in many systems where corrosion, fouling, andmicrobiological problems are potentially or actually occurring. Other tests shouldinclude, but not be limited to, flow rates, drain functions, pump tests, valve functions,sprinkler functions, pressure differentials, and trip tests of dry pipe, deluge, andpreaction valve functions.


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2.4.6 Impairment Procedures

Impairment procedures, whether for an emergency impairment or a preplannedimpairment program, vary—particularly when they involve unscheduled outage time.

2.4.7 Maintenance of Records and Reports

The maintenance of records and reports varies but should include, but not be limitedto, all inspections, performance tests, maintenance data, and chemical/microbiologicalsurvey data. Monitoring data should be made part of the records. All records andreports should be maintained so that they are readily accessible and distributed to theappropriate plant staff.


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3 PROBLEMS

3.1 Problems Impacting Fire Protection Systems

The dependability of fire protection systems (FPSs) is most important as it relates totheir capability to control and suppress fires. A number of factors (problems) have animpact on a system’s capability to carry out this function as needed. These problemsinclude (but are not limited to):

• Mechanical/physical limitations

• Plugging and fouling of the system

• Corrosion by several different mechanisms

Therefore, in the case of any emergency or preplanned impairment, it is typicallynecessary to take FPSs out of normal operating status. This often requires establishmentof compensatory measures.

3.2 Mechanical/Physical Limitations

Section 2 of this document describes the various FPS designs. Common to each type ofsystem is the fact that the major portion, if not all of the system—wet or dry, is in astagnant or stand-by mode, and the system may be activated into operation at anymoment. The flow design is typically one way, once through. The operation orperformance of the system is dependent on the function of numerous valves andpumps. The flow rate or delivery of the water is dependent on the function of a vastinterconnected network of piping, both above and below ground level.

However, the most significant limitation is the fact that FPSs are not typically designedto facilitate routine maintenance cleaning or the purging of objectionable materials thatmay have been inadvertently introduced into the system. The system design often doesnot facilitate the application of typical water treatment (corrosion control) technologies.

Mechanical problems often go on undetected, especially small losses of water from theFPS due to cross connections to other systems at lower pressures or through drainage


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lines. Valves, packing, threaded fittings, and seals are other sources of undetectedwater losses from the FPS.

3.3 Plugging and Fouling

Fouling is a broad term used to describe conditions where the presence of foreignmaterials interfere with the function of the FPS or a specific component of the FPS.Components most susceptible to fouling problems include screens and strainers, wettedmonitoring/detection equipment, sprinklers and sprays, and 2.0 inch (5 cm) or lesslateral piping and valves. Fouling is often overlooked as a cause of valve failure.Fouling can be associated with several different materials, which include:

• Microorganisms

• Macroorganisms

• Sedimentation

• Corrosion products

3.2.1 Microbiological Fouling

The uncontrolled growth of microorganisms, especially filamentous and slime-formingbacteria, results in the formation of a complex organic substance referred to as “slime”or “biomass.” This material consists primarily of substances produced bymicrobiological growth, but can include other materials that become entrained or“trapped” into the sticky slimy mass. The onset of microbiological fouling can occurwithin a very short time, that is, 6–12 hours, under optimum conditions (detailed inSection 5).

The microorganisms that are responsible for the production of the biomass are highlysessile, that is they colonize surfaces readily and are not planktonic (free floating) in thebulk water. This sessile tendency enables them to produce biomass on surfaces that areexposed to high-flow shear and frictional forces. The biomass normally cannot beflushed away from the screens, filters, pipe surfaces, or valve seats. Microbiologicalfouling is often associated with other types of fouling and corrosion and is discussedelsewhere.

3.3.2 Macrofouling

Macrofouling is associated with an accumulation of mollusks and other invertebrateorganisms within the FPS or at the intake of the makeup water. Fresh raw watersources that include rivers, lakes, and impoundments may provide the potential for


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macrofouling. The ingress of macrofouling organisms such as the Asian clam (Corbiculasp.) and the zebra mussel (Dreissena sp.) into the North American surface water sourceshas significantly increased the potential for macrofouling.

Screens and coarse filters can remove the large adult macroorganisms; however, theydo not totally remove macrofouling organisms that are in the larval, veliger, or juvenilegrowth stages. The stagnant/intermittent and low-flow conditions of the FPS allowthese motile growth stages to settle and, in some cases, actually adhere to the systemsurfaces. The occurrence of intermittent flow or the small flow rate due to leaks, etc.through the FPS headers can supply sufficient oxygen and nutrients for thelarva/veligers/juveniles to grow into reproducing adults within the FPS andsubsequently contribute to extensive macrofouling. The major consequences ofmacrofouling are the reduction of flow rates through the FPS and plugging of sprinklersystems. The provision of nutrients, especially organic nitrogen compounds, forproblem-causing microorganisms is also a major consequence of macrofouling.

3.3.3 Sedimentation

Sedimentation fouling is a result of the settling of suspended materials at stagnant orlow flow sites within the FPS. The potential for fouling by sedimentation is similar tothat associated with macrofouling. It occurs when the makeup water, without adequatepretreatment, carries material into the system, such as silt, clay, very fine sand, andother external debris. Problems related to sedimentation are not typically dependent onthe presence of nutrients or specific water chemistry. The primary factor is the presenceof contaminating materials that will settle out from the water phase.

Perhaps at any one time, the amount of contaminating material brought in with themakeup water is not very significant; however, the process of sedimentation is usuallycumulative. Over a period of time, fouling by sedimentation in systems where there isno provision for purging these materials from the system, becomes a problem. Theseverity of fouling by sedimentation is often intensified when associated withmicrobiological fouling.

3.3.4 Corrosion Products

Another significant source of materials that contribute to fouling problems in FPSs isthe corrosion product and tuberculation generated within the system itself. Corrosioncaused by electrochemical and microbiological mechanisms produces substantialamounts of suspended and deposited materials that can plug strainers, screens, filters,sprinklers/sprays, monitoring/detection devices, and other devices.

Tuberculation or nodules resulting from the growth of iron-oxidizing bacteria or fromelectrochemical corrosion mechanisms can develop to several inches in diameter and


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height. This constitutes severe fouling that can significantly reduce flow rates throughsystem piping.

The deposition of corrosion products on system surfaces has a significant impact onlimiting efforts to inhibit the corrosion. Corrosion-inhibitor chemicals are not effectivein systems where the metal surfaces are fouled with corrosion products. System designand operation of the system often limit programs designed to prevent thesedimentation of corrosion products or to remove the deposits from the inner surfacesof the system. In severe cases, isolating part of the system to flush and chemically cleanout the corrosion products may be the only option.

Microbiological fouling and the production/sedimentation of corrosion products areoften associated with each other. Together, the problems of fouling are usually moresevere than if only one of the conditions exists. Deposition of electrochemical corrosionproducts is often involved with the mechanisms of microbiologically influencedcorrosion (MIC) in FPSs.

3.4 Corrosion

Several corrosion mechanisms can affect the reliability of FPSs. Each can result in theneed for expensive mitigation programs done to make the FPS available for performingdesign functions. Corrosion results in the loss of structural integrity, weld failures,penetrations through pipe walls, loss of pumping capability, leaking of water or airpressure, degradation of monitoring/activation devices, and other problems.

Corrosion products contribute to the plugging and fouling of system components.Corrosion products tend to remain in the FPS because normal flow rates and testingprocedures do not transport the material out of the system. Most FPSs are not designedto purge corrosion products. Corrosion products, especially tuberculation, can developto the extent that flow rate through the system piping is significantly reduced.

Some of the most important corrosion mechanisms that occur in FPS include underdeposit corrosion, crevice corrosion, galvanic corrosion, and MIC. MIC is probably themost significant type of corrosion in respect to frequency of occurrence and severity.

3.4.1 MIC

Microbiologically influenced corrosion (MIC) is the term used to describe differentcorrosion mechanisms that are either induced or influenced by the growth ofmicroorganisms. The distinction is made on the basis that certain autotrophic bacteriacan actually initiate the electrochemical reactions that establish the anodic site of acorrosion cell. Other bacteria provide the cathodic site by serving as electron acceptors.


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In other words, the growth of the bacteria and the initiation or establishment of thecorrosion process is induced by microbiological metabolism.

Many other bacteria may not be directly responsible for the initiation of the corrosionprocess. However, as a result of their growth, metabolic by-products are produced thatinfluence the corrosion process. This usually involves a consortia or mixed microflorathat produces acids or alkaline compounds that alter the pH within isolated localenvirons (micro-environments) and consequently increase the aggressiveness of thewater conditions at the corrosion site. The production of sulfides by sulfide producingbacteria, including sulfate-reducing bacteria (SRB), has a major influence on thefrequency and severity of corrosion of most materials of construction for FPSs.

One of the most aggressive corrosion conditions in FPSs occurs when oxygen issuddenly introduced to a stagnant system containing H2S or metal sulfides.Microbiological growth can also influence corrosion by concentrating chlorides,sulfides, ammonia, and other aggressive ions in crevices and under deposits, and byproducing deposits that create conditions for under deposit/oxygen concentrationgradient corrosion to occur. Microbiological growth by sessile colonization of manydifferent types of aerobic and anaerobic microflora can influence the frequency andseverity of:

• Pitting corrosion

• Crevice corrosion

• De-alloying corrosion

• Galvanic (dissimilar metal couples) corrosion

FPSs are especially susceptible to MIC and the problems related to it. Stagnant andintermittent flow conditions create optimum environments for the growth of eitheraerobic or anaerobic microorganisms that can be involved with a corrosion process.System design is such that not only do optimum environments exist for MIC to occur,but also the system design limits the effectiveness of efforts (such as chemicaltreatment) made to prevent MIC.

3.4.2 Under Deposit Corrosion

Under deposit corrosion is often encountered in FPSs. This is related to the fact that twodifferent types of deposits associated with under deposit corrosion are readily formedin an FPS. The first type is tuberculation formed by either aerobic iron oxidizingbacteria or by electrochemical corrosion. Bacteria such as Gallionella sp. form tuberclesby oxidizing soluble iron in the bulk water; this soluble iron often exists because ofother corrosion in the system.


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Tuberculation can also be formed as a result of electrochemical corrosion mechanisms.The second type of deposit occurs as a result of the sedimentation and foulingdiscussed earlier. Corrosion occurring under these deposits is a result of the oxygenconcentration gradient that may exist between the surface of the base metal and thebulk water. The deposit functions as a barrier preventing oxygen diffusion from thebulk water to the metal surface, creating a corrosion cell. The driving forces for underdeposit corrosion to occur in an FPS are the presence of O2 in the bulk water and thepresence of the deposit barrier on the metal surface. Therefore, to prevent underdeposit corrosion, it is necessary to minimize or eliminate the oxygen concentration inthe bulk water and to prevent the formation of the deposits.

3.4.3 Crevice Corrosion

Crevice corrosion is often included in the definition and discussion of under depositcorrosion. However, a distinction is made here because a barrier deposit and an O2

concentration gradient may not be factors in the corrosion mechanism. Crevicecorrosion occurs in FPSs as a result of the concentration of aggressive chemicalcompounds or ions in a very localized site, such as a crevice or crack in the base metal.These materials include:

• Sulfide ions

• Metals sulfides

• Chlorides

• Organic/mineral acids

• Alkaline nitrogen compounds, such as ammonia and other primary amines

The localized crevice sites most often exist in FPS as a result of faulty fabricationprocedures, such as poor butt or socket welding and backing rings. Piping not“pickled” or passivated during fabrication can be more susceptible to crevice corrosion.Microbiological fouling and sedimentation also contribute to the existence of crevice-like corrosion sites. Therefore, to prevent crevice corrosion elimination of faults in thesystem, corrective fabrication procedures must be implemented and the system must bekept free of fouling. Preventing the existence of aggressive compounds and ions in thesystem must be implemented as well.

3.4.4 Galvanic Corrosion

Galvanic corrosion is usually a result of the coupling or connecting of components thatare composed of different materials of construction. When two dissimilar materials are


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connected and exposed to a conductive water solution, the less noble metal becomesanodic and the other becomes cathodic to produce what is called a galvanic corrosioncell. The anode deteriorates rapidly while the cathode may actually gain increasedcorrosion resistance.

The intensity of the galvanic attack is dependent on the ratio of surface area of the lessnoble (that is, carbon steel) and the more noble (that is, copper alloy) materials. If theanodic area is relatively large compared to the cathodic area, the corrosion rate isrelatively low. With the limited cathodic size, the overall reaction rate is limited by thenumber of electrons which can be accepted by the cathode. The opposite situation(large cathode and small anode) results in the rapid dissolution of the anode. In thiscase, the large cathode readily accepts all available electrons from the anodic area.

Galvanic corrosion has also been reported with cast iron and cast iron fittings. Cast ironcontains significant amounts of graphite. As the fitting ages and corrosion of the irontakes place, the graphite is exposed. Graphite is cathodic when coupled with mostmetals including cast iron and carbon steel. The result is corrosion of the iron or steeladjacent to the graphite.

FPSs have numerous sites for potential attachment of dissimilar materials. Thisnormally occurs in fire protection piping where coupling exists between brass orbronze components of the system, such as valves or sprinkler heads with iron or carbonsteel piping or a copper sprinkler piping system with iron or carbon steel mains atwelded joints with dissimilar weldment. An example would be the installation of abronze or brass valve in contact with carbon steel piping. If the metal contact is notadequately insulated, corrosion of the carbon steel will occur. Generally, the ratio ofsurface area of brass or copper components in contact with carbon steel is not sufficientto cause major failure of components such as valves, sprinkler heads, pump casings, orimpellers.

The major site of potential galvanic problems is the contact area between piping unionswith dissimilar materials. Large copper piping systems connected to carbon steel mainsor headers are high potential sites and should have dielectric union or other electricallynon-conductive breaks between them. Connections of plastic pipe to carbon steel pipingmay include a brass insert in the plastic pipe, which could initiate galvanic corrosion ofthe carbon steel.

The most common dissimilar metal couples in FPSs include:

• Carbon steel and copper alloy couples

• Carbon steel and stainless steel couples

• Stainless steel and copper alloy couples


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3.4.5 Other

Other types of corrosion mechanisms that have been reported to occur in FPSs includede-alloying, pitting corrosion, and specific corrosion of steel water storage tanks andreservoirs.

De-alloying corrosion is a process where the integrity or stability of the alloy is degraded.An example would be the leaching of zinc from a brass component such as an impellerof a jockey pump. The water chemistry could contribute to the leaching of the zinc andthe subsequent failure of the copper-zinc alloy. Another example would be thepartitioning of the graphite away from the iron component in a cast iron alloy, causingembrittlement and failure of cast iron piping.

Pitting corrosion is more of a symptom rather than a specific corrosion mechanism.There are several physical, mechanical, and microbiological circumstances that cancontribute to pitting corrosion. The common factor to all is that the situation existswhere a large cathodic surface area develops in conjunction with a very localizedanodic site. This influences the anodic activity to be in a vertical rather than lateraldirection to the metal surface, which results in pitting.

Natural waters, both potable and non-potable, are often stored in steel tanks orreservoirs for FPS make-up water supplies. Steel surfaces of tanks submerged in waterare subject to galvanic corrosion. Dissimilar metal corrosion in fire protection storagetanks can be caused by the copper or stainless steel heater coils and weld seams wherethe metallurgy of the weldment differs from the base plate metal.

Many tanks rely on coating systems for corrosion protection. Uncoated or poorly coatedtanks can have heavily corroded surfaces at lower submerged sites while the upperareas show little corrosion. This may be due to the differential oxygen concentrations inthe water (lower oxygen concentration at lower depths).

Deep vertical gouges several inches or feet (cm or m) long can occur on uncoatedsurfaces of steel tanks. This phenomenon is caused by the development of an initialcorrosion pit that generates soft oozing corrosion products. These products sloughdown the side of the tank wall, shielding the lower surfaces from oxygen andrendering them anodic.

When the internal surfaces of tanks are coated with a dielectric material (for example,vinyl or epoxy), the corrosion activity will be concentrated at the holidays or “holes” inthe coating. The holidays can result from mechanical damage, ice damage, impropersurface preparation when applying the coating, or merely very small voids in thecoating surface.


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Another significant area of corrosion concern with storage tanks is the exterior of thetank bottom due to soil-side corrosion. To deal with this potential problem, it isnecessary to determine the condition of the tank bottom. The current method fordetermination is an ultrasonic B-scan inspection of the tank in accordance with API 653,Deterministic Method. This would require draining the tank and cleaning the tankbottom.

The above corrosion mechanisms are not unique to FPSs; however, they occur in FPSson a limited basis and would occur in other systems given similar situations. There arefew, if any, treatments unique to FPSs for dealing with these types of corrosion. Theanswer is to be able to identify the mechanisms and take appropriate measures tocontrol them or eliminate them from occurring.


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4 ASSESSMENT

4.1 Discussion

Problems impacting FPS can originate soon after the system has been installed andhydrostatically tested. In some cases problems may have started even earlier—duringinstallation. This means when considering the specific procedures that must be done tokeep the FPS in optimum operating condition, it is extremely important to know theactual condition of the system at any given time.

It is necessary to implement an assessment program that is done on a regularlyscheduled basis. If chronic corrosion or other problems exist and a mitigation treatmentprogram is being done, it may be necessary to do the assessments more frequently.Assessment of the condition of the system requires comprehensive inspections,microbiological and chemical surveys, and a complete commitment to routinepreventive maintenance. The value gained from doing the assessment will be reflectedin improved system integrity, and reduced long-term costs.

If the assessment discloses that there are no significant problems, such as thosedescribed in Section 3, consideration must be given to what should be done to keep thesystem free of problems. If the assessment indicates that problems may exist, it isimportant to consider procedures to identify and treat the problem. Experience hasshown that it is frequently much more practical and efficient to prevent problems thanto mitigate them. The longer the delay in addressing a problem, the more difficult itmay become to successfully mitigate it. Prevention and mitigation actions for problemsin FPSs are discussed in Section 5.

When localized pitting or tuberculation is detected, the condition of the system shouldbe considered potentially serious. When other data, such as observed accumulations ofsediment and deposits, microbiological fouling, and certain chemical analytical results,are combined with a suspicious visual appearance, the condition of the system requiresa corrective action plan.


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4.2 Assessment Procedures

Assessing the current condition of an FPS is not an easy task. As stated earlier, systemdesign very often does not provide convenient access to many of the sites whereproblems may potentially occur. Assessing whether problems exist and, if they do, howsevere they are involves collection of data from site organizations. Categorizing thedata needed for the assessment helps to identify sites where the data may be obtained.The importance of documenting and trending the results of these assessments cannot beunderstated. Maintaining comprehensive records of previous inspections will greatlyhelp to categorize the severity and rate of degrading conditions.

The categories of assessment data include:

• Complete documentation of the materials of construction of the system

• Compilation of records of maintenance and maintenance cleaning

• An accurate and current flow diagram or CAD drawing of the system

• Documentation and assessment of the effectiveness of prior and current chemicaltreatments used in the system, including the makeup water

A review of current and historical monitoring data, which should include corrosionrates, microbiological survey results, and water chemistry analytical data, is alsonecessary for assessment procedures.

The following form provides guidelines for tabulating assessment data and subsequentreview:


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Table 4-1Fire Water System Assessment Form Date _________

Materials of Construction

Piping:

Tanks

Pumps (including impellers)

Chemical Treatment

Biocide/biostat (dosage level and frequency ofaddition)

Corrosion inhibitor (dosage level)

Biodispersant (dosage level and frequency ofaddition)

Silt/sedimentation dispersant (dosage level)

Other

Current System Data

pH

Hardness Ca

Hardness Total

TSS

Total Cu/dissolved Cu

Total Mn/dissolved Mn

Appearance (color, turbidity, smell)

Anaerobic Bacteria

SRB

Slime-formers

Conductivity

LSI/RSI/PSI

Total Fe/dissolved Fe

Nitrite/nitrate

H2S

Aerobic Bacteria

Acid producers

Mollusks


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Make-up Water Data

pH

Hardness Ca

Hardness Total

TSS

Cu T/s Cu

Mn T/s Cu

Anaerobic Bacteria

SRB

Conductivity

Hardness Mg

LSI/RSI/PSI

Total Fe/dissolved Fe

Nitrite/nitrate

H2S

Aerobic Bacteria

Acid producers

Health, Safety, & Environment Issues:

HISTORICAL DATA

Ultrasonic Testing (UT):

Radiography (RT):

Physical pipe Inspection:

Prior Chemical Treatment:

Maintenance History

(Include chemical/mechanical cleanings, piping replacements, materialchanges)

CAD Drawing (Document applicable information above)

4.2.1 Visual Appearance

Visual appearance is important, but collecting data in this category is usually limited towhen the system is not in service. Opening pipe segments of the FPS for visualinspection and sample collection should be a routine practice included in everymaintenance outage. Inspections should be made of the critical sites in the systemwhere MIC, corrosion, fouling, and sedimentation could potentially occur. Thepresence of pits, tuberculation, general corrosion, deposits/sediment, and fouling


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materials can be detected visually when they exist. Video-boroscopic and photographicprocedures are extremely useful in the collecting and documenting of visual data.

4.2.2 Microbiological Data

Microbiological data are necessary to assess the potential for MIC and fouling in thesystem. Access to sampling and microbiological culturing of the bulk water is typicallyavailable. Water samples can be taken from sites such as fire hydrants, drain lines atfire hose stations, sprinkler systems, and inspection test connections throughout theplant (for example, close to the supply and at the end of the system).

Access to sampling sessile microbiological populations from internal system surfacesmay be difficult. However, it must be emphasized that these data are very important.Swab samples (described in Section 8) should be taken every time internal surfaces aremade accessible, for example, during maintenance, inspection, and cleaningprocedures. Sessile sampling can be done on surfaces of side stream biofoulingmonitors.

The system requires immediate attention, and the conditions should be consideredpotentially serious when sulfides of microbiological origin, tuberculation, andconcentrations of biomass are detected by the microbiological survey. Procedures forperforming microbiological sampling and culturing are described further in Section 8.

4.2.3 Chemical Analysis Data

Chemical analysis data are used both to assess the potential for problems and to detectthe presence of problems. The bulk water samples collected for acquiringmicrobiological data can be used for obtaining chemical data. Additional samples fromthe makeup water system are also necessary. Obtaining chemical analytical data shouldbe done on a repeated routine basis. Comparison of the data from samples taken at aspecific frequency indicates if chemical changes are occurring in the system.Determining how and why these changes are occurring provides more information onthe actual conditions in the system.

Interpretation of these data is made by comparing the chemical characteristics of themakeup water with the second flush water. If a significant difference appears betweenthe two samples, it can be assumed that something is happening in the system, perhapsrelated to corrosion, MIC, or fouling. A comparison of the chemical characteristics ofthe first flush with either the makeup water or the second flush water will help definewhat is happening in the system.

Any rise or drop of pH, an increase in soluble iron, loss of alkalinity, presence ofsulfides, increase of suspended or dissolved solids, change in concentration of


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dissolved metal ions, for example, Cu, Ca, Mn, Mg, and Fe ions, are indications thatthere are problems or potential problems to be addressed.

4.2.4 Physical/Operating Data

Physical/operating data such as the detection of pin hole leaks or through-wallpenetrations at welds or threaded fittings are obvious indications of the existence ofcorrosion and that the conditions are severe. However, when leaks are not obvious andthere is no apparent loss of flow rate or system air/water pressure changes, NDEinspection procedures may be necessary to determine the existence and the severity ofproblems. Destructive analyses may also be necessary.

When physical and operating data point to situations that may not be confirmed byother data assembled for assessing the system conditions, it is necessary to investigatefurther to rationalize the differences. When this is completed, it can be assumed thatany problems in the system, if they existed, would be located and the severity assessed.

4.3 Inspection, Testing, and Maintenance

Every system has minimum requirements for routine inspection, testing, andmaintenance. Careful planning and accurate execution are essential to keeping the FPSin optimum operating condition. Inspection and testing provide much of the systemassessment data discussed in Section 4.2.

System components must be inspected at intervals specified by standards establishedfor the type and expected service of the system. Inspection and periodic testingdetermine what, if any, maintenance actions are required to maintain optimumoperation of water-based FPSs. The inspection standards establish minimuminspection/testing frequencies, responsibilities, test procedures, and reportingprocedures but do not define precise limits of anomalies where maintenance actions arerequired. Inspection frequencies for FPSs should be in accordance with applicableNational Fire Protection Association standards (NFPA), insurance carrier standards,and plant FPS procedures.


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Systems must be tested to verify that the items tested function as intended. Some of thetests that are significant when assessing the condition of the system with respect topotential problems include:

• Flow-rate tests

• Hydrostatic testing

• Alarm tests

The standard in the industry for inspection and assessment of condition of steel waterstorage tanks and reservoirs is AWWA D101-53. The work requires a cleaned anddrained inspection of the storage tank or reservoir. Generally, the use of a qualifiedunderwater inspection company is preferable because fire protection water supplies arenot compromised during the inspection process. The underwater inspection can offerother advantages, which include an assessment of the amount of sedimentation thatexists in the tank at the time of inspection. If significant problems are identified or siltaccumulation is large, the tank or reservoir can then be drained to correct the adverseconditions.

Maintenance must be done on a routine basis to keep the system components operableat all times. Making repairs should not be considered as routine or preventivemaintenance. Preventive maintenance is done to eliminate the need for making repairs.Installation drawings (as-built drawings), original acceptance test records, and devicemanufacturer’s maintenance bulletins should be used to assist in maintaining thesystems and the system components. Preventive maintenance includes such actions as:

• Lubricating control valve stems

• Adjusting packing glands on valves

• Bleeding moisture and condensation from air compressor/air lines

• Bleeding dry pipe system auxiliary drains

• Cleaning strainers

Corrective maintenance overlaps preventive maintenance under certain conditions.Corrective maintenance may be considered as an optional action to be done now ratherthan later. It includes, but is not limited to, replacing loaded or corroded sprinklers,replacing missing or loose pipe hangers, replacing valve seats and gaskets, and so on.


Assessment

4-8

4.4 Training

A program for training of all personnel involved with FPS chemistry control should beestablished. The training programs should be designed for the level and qualificationsof the personnel being trained. The following elements should be included:

• A clear statement of the policy regarding FPS control, including clarification of theimpact of this policy upon the various responsibility areas.

• Identification of the impact of poor chemistry control.

• Techniques for recognizing unusual conditions and negative trends. Potentialcorrective actions and their consequences should be thoroughly discussed.

The interaction of the system operations, engineering, radiation protection,maintenance, and chemistry departments cannot be overly emphasized in the operationof the FPS.


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5 CONTROL AND MITIGATION

5.1 Discussion

Control implies that problems or potential problems are currently being addressed, thatis, the conditions of the FPS are controlled to the extent that corrosion or fouling isminimized. This is the ideal situation because the control procedures are moremanageable and usually more effective than efforts made to mitigate an existingproblem. With the current technology and treatment tools available and given theopportunity to use these assets, corrosion and fouling in FPSs can be minimized. Thismay be an overstatement, but be assured that efforts to prevent problems can be muchmore successful and cost effective than efforts made to mitigate problems in most FPSs.

Mitigation implies that operation procedures, including chemical treatment, are done toat least prevent corrosion and fouling from becoming more severe, or mitigation canimply that efforts have been made for the corrosion or fouling condition to beeliminated. Several mitigation options are available. They range from on-line chemicaltreatment to replacing FPS components that have experienced damage beyond thepoint of repair. The achievement of mitigation objectives is not always as effective or ascost effective as procedures to prevent problems. Mitigation treatment programs havegenerally proven to be more expensive than control treatment programs. Mitigationoptions will be discussed later in this section.

5.2 Determining Treatment Needs to Control Corrosion and Fouling

Specific descriptions of problems that require treatment are given in Section 3. In thissection, it is assumed that the root cause has been properly identified using theguidelines presented and that specific treatment programs are being evaluated.

A treatment program to control corrosion and fouling may involve not only chemicaltreatment, but also other operational procedures such as maintenance cleaning, routineflushing, makeup water pretreatment, and in some cases, system design modifications.In addition, other considerations such as treatment costs versus component replacementcost may indicate that preplanned component replacement is the most effective systemmanagement strategy. Environmental compliance constraints may also preclude manyof the chemical treatment strategies outlined in these guidelines. Considerable


Control and Mitigation

5-2

background information is required to develop an effective control program. Thisinformation is discussed in the information that follows.

5.2.1 Materials and Design

Basically, all metallic materials of construction used in fabricating FPSs are susceptibleto corrosion and fouling; however, it is important to know where materials mostsusceptible to corrosion and fouling (for example, carbon steel) are located in thesystem. This is important because the treatment program must include provisions toensure that chemical treatment and cleaning procedures involve these sites. It is alsoimportant to ensure that chemicals used are compatible with the nonmetal materialsused as valve seats, diaphragms in deluge valves, pump seals, gaskets, etc. This issue isdiscussed in more detail in Section 5.2.6. of this document.

The method of fabrication of a specific component or piping line may relate to the needfor protection against corrosion and fouling. Information about welds, “stress bends,”flange torquing, pipe threading, butt vs. lap joints, etc. are some of the factors aboutfabrication methods that can be useful in determining susceptibility to corrosion.

System design can be a major limitation in developing an effective control program. Athorough understanding of the system flow is necessary to determine how critical areascan be flushed/cleaned and how chemically treated makeup water can reach thecritical areas. Section 2.2 discusses the numerous design options used with FPSs.Accurate isometric/piping and instrumentation drawings (P&IDs) help to visualize theflow of the water through the system during periods of testing and flushing. Dead legscan be located, and special flushing/draining procedures can be worked out. With anunderstanding of the system design, back flushing of local segments of the system andisolated draining can be accomplished when needed.

5.2.2 Makeup Water Quality and Source

Many FPSs are operated as wet standby systems, ready to be operated when the needarises. This means that the water used to initially fill the system remains in a stagnantmode for extended periods of time. The water quality should not contribute tomicrobiological growth or to corrosion and fouling. The use of makeup water with lowturbidity or silting potential is also desirable. Fresh water, rather than salt or brackishwater, is more suitable because it generally is less corrosive. Well water, rather thansurface water, is more suitable because it generally has less turbidity and silt.

The use of potable water, when available, is desired because it usually denotes that anyrequired pretreatment has been done. When potable water sources are not available forFPS makeup, separate pretreatment of the raw water at the source may be justified as a



5-3

means for preventing corrosion and fouling. Pretreatment may include clarification,hardness reduction, pH adjustment, and biocide addition.

5.2.3 Operating Considerations

There can be considerable variation in the way FPSs are operated. The proceduresdepend in part on the system design and the specifications for performance testing.Two systems may have been fabricated in the same way and look similar; however, themethods for preventing corrosion and fouling can differ depending on operatingprocedures.

System operation considerations that are related to system design are discussed inSection 2.4 of this document. Other concerns considered include:

• Use of FPS water from the system for other purposes

• Undetected leaks (perhaps from buried pipe)

• Valve leak-by

5.2.4 System Condition

The condition of the system is a result of what has occurred since the installation andoriginal hydrostatic testing were done. It is necessary to do a thorough assessment ofthe system to determine the presence of existing corrosion, deposits, or sediment oninternal surfaces; the presence of potentially troublesome types of microorganisms; andthe presence of biomass or biofouling. Assessment of system condition is discussed indetail in Section 4 of this document.

Knowledge of the system condition is necessary to determine whether a specificmechanical/physical cleaning is required or if a chemical cleaning/mitigation programmust be performed before the control can be implemented.

5.2.5 Previous Treatment Programs

It is important to have information concerning any previous treatment of the FPS. It isnecessary not only to know what the previous treatments were, but also what theresults were. The information concerning previous treatments should include data onchemical cleanings, maintenance projects, and data from all monitoring programs.Historical operating data are also important, especially if there were no previoustreatment programs. These data are discussed further in Section 4.2 of this document.



5-4

5.2.6 Compatibility

Compatibility is an issue to be addressed when selecting treatment chemicals to beused in the corrosion and fouling control and mitigation treatment programs. There areseveral compatibility interactions to be concerned about. These are:

• Interaction of treatment chemicals and materials of construction. This hashistorically not been a major problem with traditional chemicals used in FPSs. Themetallic materials are generally compatible with treatment chemicals when used atrecommended concentrations; however, some of the components have parts madeof non-metallic materials such as rubber, plastic, and elastomeric complexes. Non-metallic materials are found as valve seats, pump seals, flange gaskets, monitoringequipment, controllers, and pump and valve diaphragms and historically have notbeen a problem. Even if a non-metallic material may be adversely affected by aconcentrated treatment chemical, there may be no effect when the component isexposed to the chemical at a much lower use concentration. It is advised, however,to make studies on all chemicals considered for use in the FPS prior to use.

• Interaction of each treatment chemical with each of the others. Some biocides maynot be compatible with certain types of dispersants. Some dispersants may not becompatible with certain corrosion inhibitors. Some non-oxidizing biocides may notbe compatible with an oxygen scavenger. These incompatibilities are discussed inSections 5.6 and 5.7.

• Interaction of treatment chemicals with chemical characteristic of FPS water. Theprimary characteristics of concern are the pH of the water and the presence ofsuspended and dissolved solids. For example, the persistence or half-life of certainnon-oxidizing biocides and biostats is often pH dependent. Many of the organo-sulfur biocides have very short half-lives at a pH above 8.3. Many of the quaternaryamine biocides have cationic charges and, therefore, are not effective (compatible) ina system with water that contains high levels of anionic-charged suspended solids.Details regarding these points are discussed further in Sections 5.6 and 5.7.

• Interaction of chemicals used when implementing a mitigation treatment program.A review must be made of cleaning chemicals used when implementing a shortterm, aggressive or non-aggressive chemical mitigation treatment program. Thesystem will be exposed to the cleaning chemicals at relatively high concentrationrequired to remove the deposits. Several chemical cleaning guidelines have beenpublished that provide recommendations on the compatibility of various materialsof construction with various chemical cleaning solvents. Details on this subject arediscussed in Section 5.3. However, to ensure that incompatibility does not occur, acomplete chemical analysis of the deposits to be removed should be made.Laboratory tests to determine the cleaning effectiveness and potential corrosioneffects should be made prior to the actual mitigation treatment.



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• Interaction of chemicals with the environment and regulatory limitations. Theenvironmental compatibility and safety aspects of all chemicals used with amitigation treatment program must be assessed. The immediate issue of how thecleaning chemicals can be handled and disposed of safely without an impact on theenvironment must be resolved before the treatment is begun. Disposal of the flushand rinse water, as well as the neutralizing rinse, must be included as part of thedisposal issue.

5.2.7 Impact on Other Plant Systems

Treatment for the prevention of corrosion and fouling in FPS can have an impact onother plant systems. In most cases, the FPS is not considered to be part of the plantservice water system (SWS) or the essential service water system (ESW). However,there can be optional crossflows between the FPS and other SWS/ESW processes. Onesuch example is when the FPS water is an optional source of water to flood thecontainment in an emergency situation or when the FPS is an emergency source ofwater for the ESW. If pretreatment of the FPS makeup water is required, it is necessaryto prevent that treatment from having an impact on other uses of that makeup watersource. These are not typical situations, and there may be other situations that are site-specific. Therefore, when and if there is a chance that the chemical treatment of the FPSwill have an impact on other systems, it must be clearly identified and evaluated.

5.3 Mitigation

When it has been determined that a preventive maintenance control program will noteliminate the corrosion or fouling condition or prevent it from getting worse, severaldecisions must be made as to how to deal with the situation. In most cases, thesedecisions lead to a mitigation program. This program would seek to eliminatecorrosion or fouling or at least prevent it from becoming a contributor that wouldimpact normal plant operation. It must be noted that there are some situations wheremitigation is neither practical nor possible. Under those circumstances, the alternativesare:

• To replace the system (components) and implement a treatment program to preventthe corrosion or fouling from reoccurring

• To simply live with the condition until the first alternative can be implemented

Depending on the system and the severity of the corrosion and fouling, state-of-the-arttechnology provides some way to mitigate most existing conditions. Mitigation of theentire FPS at one time may not be practical. The system should be divided into sectorsand each stage of the mitigation program should be done one sector at a time. This isdiscussed further when reviewing the optional mitigation procedures. The procedures



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are typically site-specific, but there are certain guidelines that can be used to increasethe probability of a successful mitigation program.

5.3.1 Physical/Mechanical Cleaning

The first stage of most mitigation programs, no matter what procedure is employed, isto remove as much of the loose or loosely adhering debris from the system as possible.The debris typically consists of corrosion products, deposited sludge of variouscompositions, and biomass. Removing most of this material is usually done by a waterflushing and draining, repeated as many times as necessary. Water flushing anddraining may be supplemented with air bumping by pulsing high-pressure air throughthe pipes back to the main header.

All flushing and draining of lines with less than 2-inches (5.1-cm) ID must be done,when possible, in a reverse direction from lower ID to higher ID. In those situationswhere it is possible to open the lateral lines (ID greater than 2 inches [5.1 cm]) comingoff the main header, a high-pressure flush/hydrolazing should be used. In certain caseswhere the ID of the pipe is greater than 4 inches (10.2 cm), pigging can be used.

These techniques can effectively remove loose deposits but may not do a complete jobof cleaning the metal surfaces to which the more tenacious biomasses and corrosionproducts adhere. Flushing and draining may be considered as preparation for a morethorough cleaning procedure. In cases where the corrosion and fouling is not extremelysevere and there is a limited amount of debris associated with it, the flushing anddraining procedure is adequate pretreatment before initiating a preventive/controltreatment program. As with chemical cleaning, these waste sludges must be managedand disposed of in an environmentally acceptable manner. The impact ofenvironmental regulations should be considered prior to producing any waste stream.

5.3.2 Chemical Cleaning Methods

Chemical cleaning is the process used to follow up on the mitigation efforts ofphysical/mechanical cleaning. There are several options that can be used, dependingon the degree of cleaning required and the amount/type of deposits to be removed.When it is not possible to circulate cleaning chemicals through the system, the fill andsoak process is used. When circulation is possible, a choice of the type of cleaningchemicals must be made.

The primary choice is between using aggressive or non-aggressive chemicals.Aggressive chemical cleaning solutions are designed to dissolve the deposits. The non-aggressive cleaning solutions are designed to penetrate and disperse the deposits thatare subsequently purged from the system by flushing and draining.



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5.3.2.1 Fill and Soak Chemical Cleaning for Biofouling

A mitigation option that can be considered is using the fill and soak method, treatingone section at a time while the system is in operational condition. This option isconsidered only when it is not possible to circulate cleaning chemicals. It is used onlywhen the deposits are characterized as biofouling deposits, for example, sessilemicrobiological colonies or biomass that has entrained some amount of silt andcorrosion products.

A sector of the system is filled with a non-aggressive cleaning solution that is designedto penetrate and disperse the biomass deposits. The non-aggressive cleaning solutiontypically consists of a persistent non-oxidizing biocide, a biodispersant/penetrant, andan anionic, polyelectrolyte, low molecular weight dispersant. It is allowed to soak inthe pipes for a period of one to seven days. The sector is then drained, flushed, andfilled again with water containing more of the cleaning solution. The process isrepeated until subsequent flush samples show no further removal of deposits.

If practical, perform a visual inspection of accessible sites to determine if cleaning hasbeen complete. The final step may be to fill and flush as necessary with system water. Itis at this point that any prevention or control treatment chemicals are added to the finalfill water.

There are limitations to this option. One limitation is that the types of deposits that canbe removed are very specifically biomass and not tuberculation or adhering corrosionproducts. There must be an adequate means of draining and discharging the soakwater (cleaning solution) to a waste-receiving system that can accept non-aggressiveorganic penetrant dispersants and non-oxidizing biocides. Depending on the size of theentire FPS and whether the entire system is cleaned, the method is time consuming andlabor intensive.

5.3.2.2 Shut-Down Circulating Chemical Cleaning

When the mitigation process is limited to a short duration, an aggressive or a non-aggressive chemical cleaning solution should be used. The selection of an aggressive ornon-aggressive chemical should not be made without reviewing a complete chemicalanalysis of the deposits to be removed.

5.3.3 Aggressive and Non-Aggressive Chemical Cleaning

An aggressive chemical cleaning mitigation program involves the use of cleaningchemicals that are designed to dissolve the deposits to be removed. A non-aggressiveprogram involves the use of chemicals that penetrate the deposits and disperse(remove) them from the surfaces to which they adhere.



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5.3.3.1 Aggressive Chemical Cleaning

Aggressive chemical cleaning is used when a limited amount of down time is availableor when the mitigation process must be timed with some other maintenance activity. Itis usually necessary to use aggressive chemical cleaning solutions to remove residualdeposits not removed by the physical cleaning and flushing. Typically, these depositsare “hard tubercles” that have developed over an extended period of time.

This approach is often used to mitigate corrosion and fouling at readily isolated sites orcomponents that have access to chemical addition and the cleaning solution circulationunder controlled conditions. It is possible to set up a circulation cycle by pumping thecleaning solution from a portable tank into and through piping of the isolated sectorand then back to the tank. Chemical tanker trucks with 6,000-gallon (22,713-liter) tankshave been used very effectively for this purpose. If circulation is not possible, the filland soak method discussed earlier can be used for a short duration. However withaggressive cleaning solutions, the fill and soak procedure requires very carefullycontrolled operation because gassing and voiding may limit the effectiveness ofchemical cleaning. Localized corrosion is also a potential risk.

No matter what application approach is used with an aggressive chemical cleaning, it isnecessary to provide the capability for flushing/neutralizing the spent cleaningsolution and, after flushing, to passivate the surfaces cleaned. If passivation is not doneeffectively, you may be substituting one corrosion problem for another. The passivationprocess involves neutralizing the residual acidity during flushing, usually with NaOHor Na2CO3, followed by the addition of a passivating agent if appropriate.

Chemicals used for cleaning, neutralizing, and passivating are discussed in Section 5.4of this document. The primary criteria for selecting components of a cleaning solutionare compatibility with the materials of construction and the chemical composition ofthe deposits.

Efforts must be made to minimize the major risks associated with using an aggressivecleaning solution. It is necessary to prevent attack of the base materials of construction.This can be minimized by not overcleaning or extending the time of contact of the basemetal with the cleaning solution. The addition of acid inhibitors to the cleaning solutionwill help. The use of an acid stable, non-ionic penetrant dispersant is recommended.This type of chemical expedites the penetration of the deposits by the cleaning solutionand increases the rate of removal. It should be added directly to the cleaning solutionas the system is initially filled. Because the cleaning solution can more readily penetratethe deposits, it reduces the time that the metal surfaces are exposed to the aggressivechemicals and, in general, reduces the adverse effects that this method has on theunprotected surfaces in the system. Certain types of the penetrant/dispersant formfilms on metal surfaces that provide short-term passivation to the aggressive cleaningsolutions.



5-9

Another risk is the handling and disposal of a hazardous chemical solution. Prior to theimplementation of the mitigation program, training sessions must be held that detailexactly what is going to be done and fully cover all the safety procedures required tocarry out the program. Contingency plans must be in place and facilities availableshould some unforeseen accident happen.

It should be noted that the aggressive chemical cleaning is the most likely mitigationoption to get the FPS into an “as clean as possible” condition.

5.3.3.2 Non-Aggressive Cleaning

Non-aggressive chemical cleaning is distinguished from the aggressive cleaningapproach only by the cleaning chemicals used. It is most appropriate when any residualdeposits found after physical and mechanical cleaning are soft, porous, or primarilyorganic in composition.

The cleaning solutions are based on non-aggressive neutral or alkaline chemicals thathave a degree of surfactant activity. Included as part of the cleaning solution arechemicals with anionic polyelectrolyte properties (for example, sodium salts ofpolyacrylate, polyacrylate-acrylamide co-polymers, phosphonates, or organo-phosphates). Alkaline chelating agents can also be used. The use of a chemically stablebiodispersant is recommended with this procedure as a way to increase the penetrationof the deposits. The function of the non-aggressive cleaning solution is to penetrate anddisperse (suspend) the deposits. The biodispersant increases the probability of a morecomplete cleaning. It should be noted that the aggressive cleaning option more likelywill result in deposit-free surfaces. The non-aggressive option may not remove alldeposits, but it usually removes most of those actively involved with MIC.

It must not be assumed that the non-aggressive cleaning solution will eliminate theactivity of microorganisms contributing to MIC. A biocide/biostat treatment must beincluded as part of the mitigation process to eliminate residual microbiological growth.A biocide can be added to the rinse water or to the fresh makeup water followingcleaning. Selection of the biocide treatment is discussed in a later section of thisdocument.

The need for thorough flushing after a non-aggressive cleaning is obvious. However, inmost cases, it is not necessary to neutralize or passivate the metal surfaces that were incontact with the cleaning solution. Training and safety awareness must be consideredas a high priority just as with aggressive chemical cleaning.

The non-aggressive cleaning approach can be used only when it is possible to circulatethe cleaning solution into the sector being cleaned. The use of a portable circulationcycle discussed with aggressive cleaning can be used effectively with the non-



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aggressive cleaning. The fill and soak option has not been as effective with the non-aggressive cleaning option. In some situations, it may be necessary to repeat thecirculation stage to achieve complete mitigation. Often, the time required for non-aggressive cleaning is greater than for an aggressive cleaning.

The other risks involved with the non-aggressive mitigation option include the need toprovide a way to remove or purge the deposit debris from the system. If this is notachieved by flushing and draining, it might be necessary to install filters or screens inthe circulation cycle. A sidehill screen installed on the circulation return line to theportable tank can be used to remove much of the solids from the system.

5.4 Chemicals Used for Chemical Cleaning

When selecting chemicals to be used for chemical cleaning, the potential effectivenessof specific cleaning solutions should be tested in the laboratory or with a pilot scaletesting apparatus before being used in the FPS. A suggested laboratory test procedureis published by EPRI in the source book Recommended Cleaning Practices for Service WaterSystems.[1] A suitable pilot scale apparatus is described by Lutey and Lozier in “On-line Chemical Cleaning for Once-Through Service Water Systems.”[2]

In both cases, samples of the actual deposits collected from the FPS are exposed to theproposed cleaning solution under conditions that simulate the conditions to be used forthe mitigation treatment. Observations are made on the rate of deposits being removedand any adverse effect on materials of construction. It should be noted that allsacrificial anodes should be removed from tanks and other components prior tochemical cleaning (anodes are rarely used in piping).

5.4.1 Aggressive Chemicals

The selection of chemicals to be used as part of an aggressive cleaning solution, asstated earlier, is based on the chemical composition of the deposits to be removed andon the compatibility of the chemicals with the materials of construction. Table 5-1provides a list of commonly used aggressive chemicals and their abbreviations. Table 5-2 lists a number of aggressive chemicals that can be used with mineral (inorganic)deposits of different chemical compositions. Table 5-3 lists these chemicals versus theircompatibility with various materials of construction. Table 5-4 illustrates thetemperature limitations associated with the chemicals when used with the variousmaterials of construction. The inclusion of penetrant/dispersant compounds canenhance the dissolving activity of the cleaning solution.



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Table 5-1Chemical Names and Abbreviations

Chemical Name Abbreviation

Hydrochloric acid HCl

Hydrochloric acid - ammonium bifluoride HCl-ABF

Sulfuric acid H2SO4

Sulfuric acid - ammonium bifluoride Sulfuric-ABF

Ammoniated ethylenediaminetetraacetic acid Ammoniated EDTA

Sodium ethylenediaminetetraacetate NaEDTA

pH adjusted ethylenediminetetraacetic acid pH adjusted EDTA

Phosphoric acid H3PO4

Citric acid HO2C⋅CH2⋅C (OH)

Formic acid H⋅CO2⋅H

pH adjusted hydroxyethylenediaminetetraacetic acid pH adjusted HEDTA

Table 5-2Mineral Deposits vs. Solvents

Major Deposit Component (see key and notes)

Solvent Carbonates Phosphates

Sulfates Silica CopperOxides

IronOxides

Sulfides

HCl X X X X X

HCl - ABF X X X X X X

Sulfuric Acid X X

Sulfuric - ABF X X X

Ammoniated EDTA X X X X

Na EDTA X X

pH Adjusted EDTA X

Phosphoric Acid X X

Citric Acid X

Formic Acid X X X

pH Adjusted HEDTA X

Key:X = compatibleBlank = not compatible

Notes:1. All solvents are properly inhibited.2. Small amounts of other inorganics included with the major deposit component may not rule out asolvent choice. Solubility tests can determine this.



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Table 5-3Materials vs. Solvents - Compatibility (see key and notes)

Metals

Solvent

Carbon

Stl

Cast

Iron 300 SS 400 SS

Cu &

Alloys

Nickel

& Alloys

CR

Moly

Zinc/

Galv Alum. Magn. Titan.

HCl X A B X X X X

HCl - ABF X A B X X X

Sulfuric Acid X A X B X X X X

Sulfuric - ABF X A B X X X

Ammoniated

EDTA X X X X X X X

Na

EDTA X X X X X X X X

pH Adjusted

EDTA X X X X X X X C X

Phosphoric Acid X A X B X X X X

Citric Acid X X X X X X X X

Formic Acid X X X X X X X X X

pH AdjustedHEDTA

X X X X X X X X

Key:X = compatibleBlank = not compatibleA = max. temp. 120°F (49°C)B = max. temp 140°F (60°C)C = with proper pH

Notes:1. All solvents are properly inhibited.2. 400 stainless steels do not include free machining or sulfide penetrated materials.3. Remove sacrificial anodes such as Zn or Mg from tanks4. It is necessary to ensure that the solvent selected does not allow a subsequent precipitation of themetals dissolved onto dissimilar base metals. This will prevent a potential galvanic corrosion cell fromdeveloping.



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Table 5-4Temperature Limitations (see notes)

Solvent Max. Temp. Deg. F

HCl 175

HCl -ABF 175

Sulfuric Acid 175

Sulfuric - ABF 175

Ammoniated EDTA 325

Na EDTA 450

pH Adjusted EDTA 200

Phosphoric Acid 175

Citric Acid 350

Formic Acid 250

pH Adjusted HEDTA 150

Notes:1. All solvents are properly inhibited.2. These are maximums. Specific metals like cast iron may dictate lower temperatures.3. System design may limit temperatures.

5.4.2 Non-Aggressive Chemicals

The selection of non-aggressive chemicals for corrosion and fouling mitigation is basedon the chemical and physical characteristics of the deposits. The mechanism of firstpenetrating the deposit and then dispersing the materials is dependent on how soft orporous the deposit is, how tightly it adheres to the metal surfaces, and how muchorganic material makes up the deposit. Generally speaking, the non-aggressivechemicals are most effective with deposits that are composed of some amount oforganic materials such as biomass, microbiological slime, or grease and oils. Theorganic deposits may contain as much as 90% by weight inorganic materials such ascorrosion products that are being entrained and bound into the deposit by the organicfraction.



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Therefore, the most effective non-aggressive cleaning solutions are combinations of apenetrant (surfactant) to diffuse into the porous inorganic deposit or into the organicmatrix, and a dispersant (deflocculant) that suspends the particulate materials, notallowing them to settle out somewhere else. Examples are:

• Penetrant – Surfactant

Low-foam non-ionic EOP (ethylene, propylene oxide) surfactantSodium xylene sulfonateSodium lignosulfonateDimethylamide of fatty acid (DMAFA/DMAD)Dodecyloctyl succinateDodecyle morpholine salts (acetate)

• Dispersant - Deflocculant

Polyacrylic acid/polyacrylate (PPA/PA)1-hydroxyethylidene-1, 1-diphosphonic acid (HEDP)2-phosphonobutane-1,2,4-tricarboxylic acid (PBTCA)Sulphonated styrene/maleic anhydride (SS/MA)Polyacrylate/2-acrylamido-2-methylpropane sulfonic copolymer (PA/AMPS)Polyphosphate salts (TKPP, STPP, hexameta-phosphate)

Dosage rates for the penetrants typically range from 50–250 parts per million (ppm)active ingredient. The dispersant dosage levels would typically be 5–10 times themaximum dosage used for scale and silt control. (The dosage rate is usually limited byhow much foam can be tolerated during the cleaning process.)

The pH range of the chemically treated circulation water should be 5.0–7.5. If theacidity of the cleaning solution does not produce this pH, HCl can be used to adjust thepH to the desired range.

A shock treatment with a non-oxidizing biocide should be added to the makeup water.Selection of the biocide is discussed in a later section of this document.

5.5 Chemicals Used for Corrosion Control

Conventional corrosion inhibitors react at metal surfaces, which inhibits theelectrochemical corrosion process, an oxidation/reduction reaction. The purpose of theinhibitor is to block the flow of ions through a polyelectrolyte phase at the surface ofthe metal. The flow of ions is an integral part of the corrosion process. Some inhibitorsfunction as anodic inhibitors at the site where metal dissolution occurs. Others functionas cathodic inhibitors by affecting the reduction reaction.



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Corrosion inhibition can be achieved by the use of film-forming materials that passivatemetal surfaces by forming a protective film on the surface of the metal. There is not aspecific electrochemical reaction involved with this mechanism. Inhibitors of this typeare usually based on a composition of hydrophobic amines. They are not widely usedin FPSs because they can potentially contribute to fouling problems unless carefullycontrolled.

5.5.1 Ferrous Alloy Corrosion Inhibitors

Typical corrosion inhibitors used with carbon steel in FPSs are based onorthophosphate, organo-phosphono compounds, polyphosphate, zinc, and molybdate.Nitrites or borate/nitrites are typically not used in FPS systems because of potentialmicrobiological problems. Chromates have been used in the past but currently are notbecause of environmental regulations on the use of heavy metal inhibitors.

Table 5-5 tabulates data on the inhibitors used in FPSs for corrosion control withferrous alloys.

Table 5-5Inhibitors Used for Corrosion Control with Ferrous Alloys

Chemical

Dosage range

(ppm active) pH range Advantages Disadvantages

Environmental

Issues

Zinc 0.2–3.0 6.0–8.5 Low cost Zn stabilization

difficult at high pH

Local discharge

limitations

Organic

Phosphates

0.2–5.0 as

PO4

6.0–9.0 Low cost Possible Cuattack

Few

Inorganic

Orthophosphates

1.0–20.0

as PO4

6.0–8.0 Low cost Pitting prone

phosphatedeposits

Few

Organic

Polyphosphates

1.0–10

as PO4

6.0–8.0 Not pittingprone, revert

to

O-PO4

Phosphatedeposits

Few

Molybdates 50–200 7.5–9.0 Few envir-onmental

restrictions

High cost Few



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5.5.2 Copper Alloy Corrosion Inhibitors

The chemicals used for control of copper corrosion are generally classified as azoles.They are considered to be film-forming or anodic inhibitors. The basic chemicals of thistype used in FPSs are:

• Mercaptobenzothiazole (MBT)

• Tolyltriazole (TTA)

• Benzotriazole (BZT)

• Butylbenzotriazole (BBT)

• Modified TTA (halogen resistant azole)

The use of copper corrosion inhibitors is limited in FPSs. However, if it is necessary todeal with pH of the water in the system over 9.5 and if copper is a significant materialof construction, it is advised to consider the addition of these compounds as part of thetotal treatment program.

5.5.3 Other Inhibitors

Other inhibitor options include chemicals that are used to affect the chemicalcharacteristics of the water in the FPS. Conditioning the water to make it less conduciveto corrosion can effectively complement the addition of conventional corrosioninhibitors. For example, increased pH makes water less corrosive to carbon steelcomponents but could increase scale formation. Eliminating oxygen reduces thepotential for corrosion of most metals.

Adjusting the pH with sodium carbonate or sodium hydroxide to a range of 8.5–10.0will function to reduce corrosion and perhaps the growth rate of most MICmicroorganisms, especially the acid-producing bacteria (APB) and the slime-formingbacteria (SFB). Sodium sulfite is an effective oxygen scavenger. The addition of sodiumsulfite to provide a residual of 50–100 ppm SO3 has been effective in protecting aqueoussystems from corrosion by dissolved oxygen. This is a very effective way to eliminatethe formation of iron hydroxide/oxide tuberculation. The establishment of ananaerobic environment may appear to provide an advantage to the anaerobic bacteria.However, the prevention of tuberculation far outweighs the effect of creating ananaerobic environment when attempting to control or prevent MIC. The elimination ofO2 also provides benefits in reducing non-MIC corrosion.



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5.6 Chemical Used for Micro/Macrobiological Control

Biocides are perhaps the most critical component of a water treatment program,including that for the FPS. It is not possible to obtain maximum benefits from the othercomponents in a treatment program if microbiological growth is out of control. Thetechnology for microorganism control now includes chemicals called biocides, chemicalsfor controlling microorganisms (bacteria, fungi, and algae); and molluscicides to controlmacroorganisms (barnacles, clams, mussels, oysters, hydroids, and bryozoa). These arethe primary groups of organisms involved directly or indirectly with corrosion andfouling in FPSs. Some chemicals act as both biocides and molluscicides.

The fundamental concept of biocidal versus biostatic activity must be considered whenselecting the appropriate chemical to use in FPS. A biocide is a compound that literallykills existing macro/microorganisms. A biostat is a compound that reduces thereproduction rate of the microbiological population. It does not control microbiologicalgrowth by killing, but rather by preventing the microorganisms from reproducing(increasing in numbers) to levels where problems may occur. The selection of atreatment chemical to control micro/macroorganisms is then based on what the job isthat you want the chemical to do. It should be biocidal or biostatic or both, determinedby whether you are in control or mitigation mode.

Mitigation mode treatments require killing or eradicating existing populations ofundesirable types of macro/microorganisms. The job to be done is “quick-kill” theexisting population and then no longer be part of the environment. This is a biocidalfunction. The prevention mode treatment requires the chemical to persist in theenvironment for an extended period of time to provide biostatic activity, controlling thepopulation from reproducing to critical levels.

Some non-oxidizing biocides have both biocidal and biostatic properties. A persistentbiocide/biostat should be used when it is expected that the system will be in anextended wet lay-up condition with little or no makeup water added. This is a typicalFPS operation mode. Oxidizing biocides can effectively provide a quick-kill functionbut are not typically used to provide a biostat function.

The compound selected for FPS microorganism control, including MIC, should haveefficacy as a biocide/biostat for those microorganisms involved with MIC. Generally,these include sulfate-reducing bacteria, iron/metal-oxidizing bacteria, acid-producingbacteria, and slime-forming bacteria. In some circumstances, nitrogen compoundmetabolizing bacteria can be a concern. There continues to be more informationbecoming available that fungi may be a concern with MIC but not typically in FPSs.

Recent publications illustrate that macrofouling by the mollusk groups mentionedearlier has become a major challenge in FPSs. The fouling problem is increasing infrequency and severity. There is now evidence that macrofouling can be associated



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with severe MIC even in closed systems, including FPSs. Therefore, when utilizingsurface water makeup sources, it is becoming increasingly important to select treatmentchemicals that potentially have both macrofouling and microfouling controlcapabilities.

5.6.1 Chemical Used as Biocides/Biostats

5.6.1.1 Oxidizing Chemicals

Oxidizing biocides are chemicals whose effectiveness depends upon their ability tooxidize and thus destroy organic material. Their biocidal action is based on oxidizingthe microorganisms and, in some cases, the organic materials that serve as nutrients forthe microorganisms. The oxidizing biocide is consumed as it oxidizes the organicmaterial, leaving no residual oxidation potential and, therefore, no biostatic activity.The chemistry, advantages/disadvantages, and application information on oxidizingbiocides are tabulated in Tables 5-6, 5-7, and 5-8.

Table 5-6Oxidizing Chemicals for Microbiological Control

ChemicalTargeted

Organisms

ResidualDosageRange(ppm)

pHRange Advantages Disadvantages

EnvironmentalIssues

Chlorine B, IDB, A, 0.1–1.0FAO

6.0–7.5

Low cost Corrosive,haz gas

Broadrestrictions

Sodium Hypochlorite B, IDB, A, 0.1–1.0FAO

6.0–7.5

Low cost Poor kill @higher pH

Dischargerestrictions

Chlorine/BromineLiquid

B, Bsp,SRB, IDB, A

0.05–0.5FAO

6.0–9.5

Effective @higher pH

Moderatehigher cost


Chlorine/Bromine;Solid Hydantoins

B, Bsp,SRB, IDB, A

0.05–0.50FAO

6.0–9.5

Effective @higher pH;handling

Higher cost; lowsolubility;pressure

limitations


Chlorine Donor; SolidChloroisocyanurates

B, IDB, A, 0.10–1.0FAO

6.0–7.5

Handling Higher cost Dischargerestrictions

Chlorine/Br Donor;Solid

Bromo-ChlorinatedIsocyanurates

B, Bsp,SRB,

IDB, A

0.05–0.50FAO

6.0–9.5

Handling Higher cost Dischargerestrictions

Chlorine Dioxide B, Bsp, IDB,A

0.1–1.0FAO

6.09.5

No ammoniareact; no

THMs

Hazardous;explosive


Hydrogen Peroxide B, Bsp,IDB, A, F

0.2–3.0FAO

6.0–9.5

Decays tooxygen

and water

High cost; slow None



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KeyB = bacteria, slime formersBsp = bacteria, spore formersSRB = sulfate-reducing bacteriaIDB = iron-depositing bacteriaA = algaeF = fungus

Note: The free residual oxidants (FAOs) shown here are generally considered effective in FPSapplications. Actual residuals needed are site specific and may be higher or lower depending oncircumstances.

Table 5-7Non-Oxidizing Biocides

ChemicalTargeted

OrganismsDose

Range(ppm)


Environmental Issues

Ionene Polyquats B, Bsp, SRB,IDB, A

5–20 6–9+ Effectivebiostat

Not effectivehigh turbidity

Low Effluentbiotoxicity

QuaternaryAmines(Quats)

B, Bsp, SRB,IDB, A

10–100 6–9 May foam;cationic

(deactivatedispersants);

hardnessreaction

Effluentbiotoxicity

MBT B, Bsp, SRB,IDB

1–8 <8.3 Shorthalf-life

Effluentbiotoxicity

Organo-Sulfur(carbamates)

B, Bsp, SRB,IDB

50–50 6.5–9.0 Corrosive tocopper

Effluentbiotoxicity

Isothiazoline B, Bsp, SRB,IDB, A, F

1–5 6–9 Hazardous; lesseffective in low

TH water

Effluentbiotoxicity

Glutaraldehyde B, Bsp, SRB,IDB, A

50–100 6.5–9.0 Degrades toCO2 & H2O@ pH ~9

Deactivated byNH3

Effluentbiotoxicity

KeyB = bacteria, slime formersBsp = bacteria, spore formersSRB = sulfate-reducing bacteriaMBT = methylene bis thiocyanateIDB = iron-depositing bacteriaA = algaeF = fungus



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Table 5-8Chemicals for Macrobiological Control

ChemicalTargeted

OrganismsDose

Range(ppm)


EnvironmentalIssues

Chlorine AC, ZM,AO, H, BM

0.1–1.0 6.0–7.5 Low cost Corrosive gas Broadrestrictions

Sodium Hypochlorite AC, ZM,AO, H, BM

0.1–1.0 6.0–7.5 Extendedre-application

Broadrestrictions

Chlorine/BromineLiquid

AC, ZM,AO, H, BM

0.1–1.0 6.0–8.5 Extendedre-application

Broadrestrictions

Quaternary Amines(quats)

AC, ZM,AO,BM

1.0–3.0 <9 Persistent Not effectivehigh turbidity

Minimalrestrictions

Ionene polyquats AC, ZM,AO,BM

2.0–20 6.0–9+ Persistent Not effectivehigh turbidity

Minimalrestrictions

KeyAC = Asian clamsZM = zebra musselsAO = American oystersH = hydroidsBM = blue mussels

Chlorine and chlorine-producing compounds are the most widely accepted form ofoxidizing biocide in cooling water and other process water systems. However, theirroutine use, including that in FPSs, for microbiological (MIC) control is limited by threefactors. If incorrectly applied, they:

• Contribute to increased corrosion

• Have reduced effectiveness/lower efficacy at pH above 8.3

• Possess a non-persistent residual that provides no biostatic activity

When dealing with a pH above 8.0, bromine-based oxidizing biocides should beconsidered.

Oxidizing biocides used to pretreat makeup water and to treat FPSs specificallyinclude:



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• Chlorine based

Chlorine gas (seldom used in nuclear plants)Sodium hypochloriteCalcium hypochloriteDi/tri-chloro-isocyanuric acidChlorine dioxide

• Bromine based

Hypobromous acid (HOBr) , activated NaBr in situStabilized hypobromiteBromo-chloro dimethyl hydantoinBromo-chloro methylethyl hydantoin

• Hydrogen peroxide (H2O2)

5.6.1.2 Non-Oxidizing Biocides/Biostats

Non-oxidizing biocides are chemicals that control the growth of microorganismsthrough a toxic mechanism rather than by an oxidation process. The mechanism oftoxicity can be as a systemic poison, by cell structure disruption, or by prevention ofoxygen transfer. Some of the chemicals have a broad spectrum of activity againstbacteria, fungi, algae, and macrofoulers under a broad range of environmentalconditions. These are called “broad spectrum biocides.” Others have very focusedactivity against specific types of microorganisms under a narrow range ofenvironmental conditions. Many of the original biocides were based on either phenol orheavy metal chemistry to provide the toxic mechanism. Because they persisted for along period of time, they also provided excellent biostatic activity. However, thesetypes of materials were very abusive to the local environment. They are no longerpermitted for use by most regulatory agencies.

The environmentally friendly compounds used as biocides have toxic mechanisms butare designed to kill the microorganism and not persist in a toxic form in theenvironment. For this reason, very few compounds now available have biocidal as wellas biostatic activity against the microorganisms associated with problems in FPSs.There are many different compounds and blends of compounds that are used inprocess cooling waters.[3]

The non-oxidizing biocides/biostats that have been used in FPSs include the following:

• Organo-sulfur (carbamates) compounds

• Glutaraldehyde (1,5-pentanedial)



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• Isothiazolone

• Quaternary ammonium salts (quats)

• Ionene polymeric quaternary ammonium compounds (polyquats)

• Methylene bis thiocyanate (MBT)

Organo-sulfur (carbamates) compounds – These are sodium or potassium salts ofdimethyldithiocarbamates. They are broad spectrum biocides that have efficacy againstaerobic and anaerobic bacteria associated with microbiological problems in FPSs. Theiroptimum pH range is 6.5–9.0. Typical dosages are 25–50 ppm active ingredient. Underoptimum conditions and at the maximum dosage, the carbamates can provide limitedbiostatic activity.

Limitations are that they form a complex on copper surfaces that reduces theireffectiveness. Use of an azole inhibitor overcomes this limitation to some degree. Thecarbamates will also complex with suspended or soluble iron to form an insolubleprecipitate.

The carbamates have no known activity against macrofouling organisms and are notE.P.A. registered for molluscicide application.

Glutaraldehyde – This material has efficacy against fungi and anaerobic/aerobicbacteria associated with microbiological problems in FPSs. It is a broad spectrumbiocide, effective over a broad range of pHs and temperatures when used at maximumdosage levels. Glutaraldehyde is compatible with most corrosion and scale inhibitors.Its effectiveness is enhanced when used with penetrants/dispersants. It is generallynon-foaming, odorless, and non-corrosive to most materials of construction atrecommended use levels. The active concentration in treated water can be measuredwith a field test kit.

Typical dosage levels are 50–100 ppm active ingredient.

Limitations are that the half-life of glutaraldehyde is relatively low at the pH rangesfound in FPSs. Therefore, to persist and provide biostatic activity, high frequencyadditions are necessary (weekly to monthly).

Glutaraldehyde is not E.P.A. registered for use as a molluscicide.

Isothiazolone – This is a mixture of 5-chloro-2-methyl-4-isothiazoline-1-one and 2-methyl-4-isothiazoline-3-one. It is a broad spectrum biocide with efficacy against algaeand sessile aerobic bacteria. It is effective against anaerobic bacteria including SRB



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when used with a penetrant dispersant so the biocide can penetrate into the biomass.The pH range is 6.5–9.0 with 8.0 being optimum.

The persistence, or half-life, is significantly reduced at pH above 8.0. Therefore, toprovide biostatic activity, high frequency dosages are often necessary (weekly tomonthly) when used in FPSs. Isothiazolone is hazardous to handle because of its highdermal sensitivity/toxicity. Application with dosing equipment should be considered.Typical dosage levels are 2–5 ppm active ingredient.

Isothiazolone is not E.P.A. registered for use as a molluscicide.

Quaternary ammonium salts (quats) – The quats are a group of cationically chargedammonium compounds of fatty acids with varying carbon-chain lengths. A typical quatof this type is alkyl dimethyl benzo ammonium chloride (50% C-14, 40% C-12, 10%C-10). The chain length is relevant to the dispersibility/solubility of the compound inwater and, thereby, indirectly to its efficacy. These compounds have good biocidalactivity against aerobic and anaerobic bacteria in FPSs. The quats are broad spectrumbiocides under a wide range of pHs and temperatures. When used in systemscontaining relatively low turbidity and suspended solids, the quats provide adequatebiostatic activity in FPSs.

Many of the quat formulations are surface active, which assists its activity againstsessile organisms. However, this may create undesirable foaming conditions whenused at the higher dosage levels. The cationic charge density may result in someincompatibility with anionically charged scale inhibitors and silt dispersants. Highdosage levels are required when used in saltwater or in water with high concentrationsof suspended solids.

Typical dosage levels are 10–100 ppm active ingredient. The active ingredientconcentration in treated water can be measured by using a field test kit.

Some of the specific quaternary ammonium salts, such as the example above, are E.P.A.registered for use as a molluscicide. Under certain treated water discharge conditions,detoxification treatment may be required.

“Ionene” polymeric quaternary ammonium compounds – These are referred to aspolyquats or polyionene quats. An example ispoly[oxyethylen(dimethyliminio)ethylene(dimethylimino)ethylene dichloride].Although the compound contains quaternary nitrogen, its chemistry is significantlydifferent from the alkyl-benzo-ammonium chloride salts. The polyquats are lowmolecular weight ionene polymers. Ionene designates that the quaternary nitrogen iscontained in the polymer chain, making the compound chemically very stable. Thecationic polymeric characteristics enable the compound to concentrate microflocs of



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microorganisms, thereby reducing the minimum inhibitory concentrations required tocontrol the growth of microorganisms.

The polyquats have efficacy as biocides against the aerobic and anaerobic bacteria thatcause microbiological problems in FPSs. They are low-foaming and effective under awide range of pHs and temperatures. High levels of total dissolved solids or chloridesdo not limit its effectiveness. They are totally water soluble and persistent, enabling theactive ingredient to diffuse into water-filled “dead-leg” piping in an FPS. They havevery low dermal toxicity.

The primary limitation of the polyquats is that their effectiveness is reduced when usedin waters with high turbidity or suspended solids. Polyquats are not normally used inmitigation programs.

Typical dosage levels in FPSs are 5–20 ppm active ingredient. The active ingredientconcentration in treated water can be measured by using a field test kit.

Formulations of polyquats are available that have been developed specifically for use incontrolling mollusks. Commercially available products based on polyquat chemistryhave been E.P.A. registered for use as a molluscicide in fresh water and seawater (once-through, circulating, and closed process water systems).

Methylene bis thiocyanate - MBT – MBT is not a broad spectrum biocide. It is usedalone or blended with other active ingredients to provide highly effective biocidalactivity against specific types of microorganisms, particularly aerobic and anaerobicbacteria including SRB. It is used to provide a quick-kill function in mitigationtreatments in FPSs, but not usually as part of a maintenance/control treatmentprogram. MBT hydrolyzes rapidly at pH above 7.5 and as a quick-kill biocide does notprovide significant biostatic activity.

MBT is hazardous to handle with high dermal sensitivity/toxicity. Therefore, dosingequipment should be considered. Typical dosage levels are 2–10 ppm active ingredient.

MBT is not E.P.A. registered for use as a molluscicide.

5.6.2 Non-Toxic Control Chemicals

The traditional approach to macro/microorganism control has been to kill themacro/microorganisms or at least prevent them from reproducing. Current developingtechnology has demonstrated that other options may be used to controlmacro/microbiological problems. The driving force behind the development of thistechnology is eliminating the need for toxic compounds to control



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macro/microbiological growth. In most situations, this is much more acceptable froman environmental stewardship position.

Enzymes - One option is the use of enzymes that interfere with the process ofcolonization by microorganisms. These enzymes do not kill the microorganisms. Theysimply alter the ecology to the extent that the microorganism cannot cause problems.Lack of colonization subsequently reduces the ability of the microorganisms to survivein many environments. They eliminate the formation of biomass and biofouling oninternal surfaces of FPSs. Commercially available formulations of non-toxic enzyme-based products are now being tested under actual operating conditions. The enzymesinclude proteases, lipidases, carboxylases, amylases, and xylenases. Some productsbeing tested involve blends of different types of enzymes. Progress of this developingtechnology is discussed in the literature.[4]

Biodispersants - Biodispersants are chemical compounds that disperse biofilm orbiomass within the bulk water or from sites where it is attached to the surfaces in asystem. Their most important function is to disrupt sessile colonization of themicroorganisms that leads to biofouling and MIC. Biodispersant technology is not new.It has been used for several years as a means to enhance the activity of both oxidizingand non-oxidizing biocides. However, recently dispersant technology has provided anumber of new non-toxic chemical compounds that have interesting biodispersantproperties. A few based on dodecyl-amine chemistry, have become commercialproducts with claims of controlling certain microbiological problems without the use oftoxic chemicals.

5.6.3 Non-Chemical Control Options

Several non-chemical control approaches have been tested to control MIC,microfouling, and macrofouling in many types of industrial process water systems.These have been relatively successful in a few types of systems. However, only limitedsuccess has been achieved with non-chemical treatment in FPSs. Non-chemicalapproaches include:

• Thermal treatment

• Filtration and straining

• Ultraviolet radiation

• Various “black box” magnetic

• Heavy metal ionization devices

• Predatorial organisms



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• Coatings and linings

• System and water velocity designs

• Ultrasonic treatment

Some think that microbiological and corrosion-resistant coatings offer some degree ofpotential control in FPSs. Recent advances in coating technology and the applicationmethods of coatings have proven to be of some benefit. Cement linings,thermal/solvent set epoxy coatings, and synthetic elastomeric coatings have providedbenefits when the coatings were “shop applied” to components used for replacementmaintenance. In situ type linings and inserts have been installed in a limited number oflarge diameter buried FPS pipeline and headers. Results to date appear to be favorable.

It is the general consensus at this time that non-chemical control procedures still requirefurther development and, for the near future, supplemental chemical treatments arestill needed.

5.7 Fouling Control

Fouling or siltation is the result of the deposition of suspended solids. For thisdocument, biofouling has been discussed as a separate issue. Suspended solids aredefined as any insoluble (filterable) material in the water. Materials that are included inthe definition of suspended solids are:

• Silt

• Fine silica

• Organic debris

• Oil and grease contaminants

• Corrosion products

Much of the suspended solids are carried into FPSs with the makeup water. Limitedamounts of suspended solids are formed within the system. Therefore, since the totalvolume of water added to the system following initial makeup is low, fouling or siltingproblems are typically minimal in FPSs. Perhaps the greatest source of troublesomefouling materials is corrosion products generated by corrosion within the system itself.In many cases, controlling corrosion results in controlling most of the fouling thatoccurs in FPSs.



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In very rare cases, suspended solids can be generated within the system as a result ofprecipitation of incompatible treatment chemicals. The actual fouling occurs at siteswhere the flow velocity is low (< 2 ft/sec.[< 0.6 m/sec.]) or as a result of stagnantconditions during wet lay-up operation typical to FPSs.

5.7.1 Chemicals Used for Fouling Control

The ideal approach to fouling control should be to limit the intrusion of suspendedsolids into the system and to prevent subsequent precipitation and corrosion within thesystem. However, chemical control processes are most typically used for fouling controlin FPSs.

Silt/inorganic suspended solids - Silt and other inorganic suspended solids arecontrolled by the addition of dispersants composed of acrylate-based polymers, such aspolyacrylic acid or sodium polyacrylate. In addition to the acrylates, polyacrylamidesand acrylamide/acrylate copolymers are also applicable.

Typical dosage levels depend on the amount of foulant to be dispersed. They rangefrom 1–5 ppm active ingredient.

Sludge - Occasionally, sludge fluidizers are required when the suspended solids areprimarily organic debris. The most common sludge fluidizers are water-soluble, long-chain, high molecular weight polyacrylamides. The polymer prevents the packing ofthe debris into a dense sludge. This allows the debris to remain fluffy and can easily beflushed from the system.

Typical dosage levels are 0.02–0.5 ppm active ingredient. Care should be taken not toovertreat because excess polymer can contribute to fouling.

Oil/grease and other organic suspended solids – Oil and grease contamination can becontrolled by the addition of surfactants that are classed as wetting agents or lowfoaming surfactants. They act by emulsifying and dispersing the oily or slimysuspended solids. In some cases, the surfactant can actually strip the depositedsuspended solids from the fouled surfaces. These materials may already be part of thetotal treatment program used as biodispersants discussed earlier. If not and if treatmentis needed, the surfactant is added as a shock treatment.

Typical shock treatment dosage levels are 10–50 ppm active ingredient.

5.7.2 Non-Chemical Means of Fouling Control

In addition to chemical methods of fouling control, there are mechanical means ofmitigating suspended solids problems. They include mechanical pretreatment of the



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makeup water by filtration and clarification. Full stream or sidestream filtration of theFPS water can be done when chronic suspended solids problems occur.

Periodic mechanical/physical cleaning, usually by the flush and drain procedure, wasdiscussed earlier as a primary method for controlling fouling. See that section forfurther details on non-chemical methods of suspended solids control.

5.8 Non-Chemical Corrosion Control

Most FPSs have some components that consist of tankage and buried pipe. Thesecomponents are often constructed of carbon steel or other materials that are susceptibleto corrosion. The procedures for controlling this corrosion are not unique to FPSs.Reference to published guidelines should be made for the specific details on non-chemical corrosion control programs.

Corrosion control of the interior surfaces of tanks and pipe should be part of the overallchemical treatment of the FPS water system. Corrosion control of the exterior surfacesof tanks and buried pipes is based on non-chemical methods such as coatings and/orcathodic protection technology.

5.8.1 Non-Chemical Corrosion Control of Tanks and Buried Pipe

5.8.1.1 Coatings

The FPS water storage tank may rely on a coating system to protect the tank. AWWAStandard D 102 is the standard reference for the proper installation of tank coatings.The coating system may be the only corrosion protection for the tank. These aregenerally designed to last up to 10 years The coating systems have been improved overthe years, and many now are dielectric material such as vinyl- or epoxy-based coatingswith up to 50-year life spans. The coatings have various immersion resistance outlinedin NACE Standard Test Method, TM-01-74, “Laboratory Methods for the Evaluation ofProtective Coatings Used as Lining Materials in Immersion Service.”

Underground piping is typically protected against corrosion by the use of various typesof coating or coverings (wrappings). The degree of protection provided depends on:

• Previous treatment of the surface to be coated or wrapped

• Coating thickness

• Uniformity and flaw-freeness of application

• Properties of the coating binder, pigment, and other additives



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Protection is ensured only if the coating is free from faults. Faults render the pipe moreeasily penetrated by water and cause localized corrosion sites. When laying piping inrocky ground or gravel, particular attention must be paid to ensure that the coating isnot damaged by stones.

Wrappings are used mostly with underground pipe. Pipe wrappings must satisfy thefollowing requirement:

• Temperature stability

• Resistance to aging or oxidation

• Resistance to impact and indentation

• Distensibility

• Good adhesion to the substrate material

• Chemical resistance

• Low water vapor and oxygen diffusion rates

• Electrical insulation capacity

Corrosion protection tapes made of various plastics have recently become available. Ifthe installation standards for wraps and the processing instructions of themanufacturers are carefully followed, underground piping may be reliably protectedfrom corrosion in the long term.

All coatings can fail and are extremely susceptible to damage. Once they are damaged,the area becomes an accelerated pit corrosion site, and the failure probability isincreased.

5.8.1.2 Cathodic Protection

Galvanic cathodic protection (sacrificial anodes) is not generally recognized as amethod to protect submerged surfaces of piping or storage tanks. The only feasiblereason to permit this type of protection is if it is not possible to get a dc power supplyto the component. The sacrificial anodes used cannot vary the protection current and,therefore, problems of over- and underprotection can occur.

However, impressed current cathodic protection (ICP) is used with both storage tanksand buried piping. The two major components of impressed current protection systemsare the dc power supply controller (rectifier) and the anode system. The range of



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output current capacity required by the rectifier is determined by assuming the area ofbare steel to be protected, 20% of the submerged surface area before recoating forcoated tanks, and the submerged area for uncoated tanks or piping.

The second major component of an ICP system is the anode system. The type of anodematerial and the type of suspension system is typically based on the component’ssusceptibility to icing conditions. Seasonal or long-life anode systems are available.Seasonal designs consist of aluminum rods installed and serviced through an accesshole in the component (for example, roof of the tank). Long-life anode systems includesuspension systems that are ice resistant and use materials that have a designed life ofup to 20 years.

Flaws in coatings or wrappings on buried pipe are difficult to avoid in actual practice.Therefore, ICP is often used in conjunction with coatings or wrappings. The protectivecurrent requirements of the ICP system are reduced by coating or wrappings.Suggested methods of ICP for buried pipe in soil are tabulated in Table 5-9.

Table 5-9Cathodic Protection Criteria for Buried Pipe

Mean SoilResistivity(Ohm/cm) Rating of Soil Possible Method of Protection

100,000–25,000 Not corrosive CP not necessary with uniform soils

25,000–10,000 Hardly corrosive CP may not be necessary orICP/Mg anodes (1.6 kg)

10,000–5,000 Slightly corrosive Impressed current/Mg anodes(1.6 or 3.6 kg)

5,000–2,000 Moderately corrosive Mg anodes (5–8 kg) impressedcurrent

2,000–1,000 Highly corrosive Mg anodes (8–10 kg) impressedcurrent

Under 1,000 Very highly corrosive Impressed current, MG & Znanodes (10–15 kg), No Mg ifpH <4.0

Properly maintained impressed current cathodic protection systems for uncoated orcoated tanks with holidays can be protected from corrosion. A coating’s major functionwith a cathodically protected tank is to reduce the cost of power to protect the tank andreduce the rate of anode consumption.



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There are significant differences in manually and automatically controlled systems.Automatically controlled ICP systems use one or more long-life reference electrodesthat continuously monitor the protection levels maintained on the submerged surfaces.The reference electrode continuously determines tank-to-water potential. A controllercompares actual tank-to-water potential to a preset value and automatically adjusts theoutput of the rectifier. The system needs to be maintained and adjusted to workproperly, but this represents the best protection available for the water storage tank.

Manually controlled rectifiers are generally not recommended for use with waterstorage tanks because they require frequent monitoring, testing, and manualadjustments of the rectifier current output when current requirements change due tochange in operating conditions in the tank. Failure to adjust current output can result incorrosion due to underprotection or coating damage due to overprotection.

5.8.2 Accumulation of Foreign Materials on Sprinklers

Sprinklers may be located in atmospheres that are corrosive or cause an accumulationof foreign materials to adhere to the sprinklers. This is called loading and can increasethe sprinkler activation time or cause it to fail. Sprinklers should be selected for theenvironment they are intended to operate in and be inspected for the accumulation offoreign materials.

5.8.3 Dry Piping in Dry Pipe Sprinkler, Deluge, and Preaction Systems

Dry sections of these systems must be maintained dry. These systems have proven tocorrode at a higher rate than wet piping due to improper or incomplete draining,leakage of valves, or repeated inadvertent system trips. In all cases, the water must bedrained completely. Low point drains must be identified and used. Sloped systemsneed to be reviewed to determine if adequate slope is provided to the drains. Drysections of these systems corrode at a higher rate due to the availability of oxygen whenwater is present.

The condensation of moisture in the air supply of dry sprinkler systems may result inhard scale forming on the bottom of the piping. These systems should have adequateair dryers that are properly maintained and inspected for efficient operation.

5.8.4 Foam-Water Systems

Foam leakage and mixing with water in foam-water systems is a significant problem inthese systems. The boundary between the foam and the water must be maintained.Foam concentrates mixed with water adhere to interior surfaces of piping, reducing theeffective diameter of the piping or causing complete blockage in severe cases. This



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boundary must be inspected and maintained, and the piping needs to be internallyinspected in these areas at each possible opportunity.

5.8.5 Other Non-Chemical Corrosion Control Procedures

Corrosion of storage tanks and buried pipe is also occasionally prevented by suitablesoil treatment instead of protective coatings or cathodic protection (CP). Protection isprovided by embedding pipe in pipe trenches or tanks in tank pits with a stone-freesand or lime layer not less than 20–25 cm thick. Alternatively, a soil neutralized withlime can be used.

Back-filling pipe trenches with sand offers good long-term protection in corrosive clayor plastic clay soils. The protective effect of the sand packing in poorly drained soils isinsignificant since the exchange of corrosive substances is not prevented.

Plastic piping is increasingly used today instead of metal piping in particularlycorrosive soils.

Specific measures that may provide some degree protection against MIC in soil include:

• Aeration or sulfide precipitation when SRBs are present in the soil

• Application of resistant coatings or wrappings

• Cathodic protection (more negative cathodic protective potentials have to be appliedin the presence of SRBs)

• Addition of heavy metal salts (such as copper, chrome, zinc, selenites) or specificbiocides into the soil where environmental regulations will allow

Note: The fact that archaeological finding of iron had not corroded even after 2000years in soils containing SRBs is due to the fact that soil contained stannates, whichcounteract the effects of the bacteria.

5.9 Regulatory and Registration Considerations

The guidelines presented in this document include discussions related to non-chemicaltreatment procedures to control corrosion and fouling. In some plants, the FPS cannotbe chemically treated using traditional methods for control or mitigation purposesbecause of system design and limitations associated with environmental regulations. Inthese cases, chemical treatment may not be a viable option for controlling corrosion andfouling in FPSs. Non-chemical procedures may be the only option. The guidelines areintended to be flexible and support the need to assess the problems on an individual



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site and system basis and then make a determination of what is to be done on anindividual value and cost assessment.

The use of all treatment chemicals for control and mitigation programs in FPS must be“approved” under current code, safety, and environmental regulations. Theseregulations are administered by local, state, and federal agencies. The regulations dealwith:

• On-site storage of treatment chemicals

• Application procedures

• Disposal of containers

• Disposal of unused treatment chemicals

• Discharge of water containing treatment chemicals

• Discharge of sludge and waste water containing treatment chemicals

• Compliance with local, state and federal regulations

• Compliance with licensing requirements

The responsibility for ensuring that the regulations are complied with is usuallyassigned to the environmental, safety, and support engineering departments at mostnuclear facilities. Their efforts should be supported by collaboration with the vendorsor suppliers of the treatment chemicals.

The manufacture and use of biocides/biostats are regulated by the Federal Insecticide,Fungicide, and Rodenticide Act (FIFRA). The manufacturers must have E.P.A.registration and approved labels for each type of application of the compound. Themanufacturer can sell active ingredients only to formulators or end-users that havetheir own registration or subregistration and approved labels.

The manufacturer/vendor is obligated by law to provide the end-user with currentMaterial Safety Data Sheets (MSDSs) and labels that specifically define:

• The approved type of use and dosage levels

• Manufacturer’s name and address

• Chemical name of active ingredients and concentration in product

• E.P.A. registration number, if required



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• Health, fire, chemical reactivity, and explosive hazard data

• Toxicological and aquatic toxicity data

• Handling, storage, and disposal procedures

• Description of special precautions and protective equipment required

All nuclear power generation plants have a program to monitor chemical treatmentprocedures that ensure compliance with all applicable regulations.


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6 PERFORMANCE MONITORING

6.1 Discussion

This discussion relates to assessing the performance of corrosion and fouling controlmeasures used in FPSs. Assessment of the performance of the FPS itself is discussed inSection 4 of this document.

Monitoring involves the process of gathering data on specific criteria over a period oftime for the purpose of determining whether system conditions and control procedureshave been maintained at the specifications considered necessary for compliance of thesystem to its function. This determination is based on a comparison of currentconditions with past conditions. In this sense, the monitoring procedure is consideredto be gathering “historical data.” Historical data provides the basis for detectingwhether changes in operating conditions have occurred over a period of time andwhether adjustments in the control procedures are required. For example, these datacan be used to determine what effect changes, such as change in makeup watertemperature, have on the performance of treatment chemicals and on the corrosionrates.

Monitoring also involves the process of performing specific tests to indicate what theconditions are at the time of the tests. In this sense, the monitoring procedure isconsidered to be the gathering of “real-time data.” Real-time data are used to confirmthat the control parameters are adequate and meet the specific conditions of the controlprogram.

The objective of the control program is to control corrosion and fouling in order toprevent their limiting the designed function of the FPS. The objective of performancemonitoring is to:

• Confirm that the control program performance parameters are being maintained.

• Confirm that performance goals are being met.

• Identify adverse trends in a timely manner.


Performance Monitoring

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The tools used for performance monitoring are not significantly different from thoseused in closed loop cooling water systems (CCW), service water systems (SWS), orcondenser cooling water systems. However, because of some of the uniquecharacteristics of FPSs, the procedures for using these tools may require somemodifications.

Performance monitoring of FPS control programs is dependent on several factors thatinclude:

• System metallurgy

• System design

• System integrity specifications

• Characteristics/specifications of the chemical treatment control program

• Current system operating conditions

• Site-specific history of performance and operating conditions

• Selection and accessibility of the monitoring site

Techniques widely used for performance monitoring in FPSs include:

• Corrosion monitoring techniques

• Fouling monitoring techniques

• Microbiological monitoring techniques

• Visual inspections

• Nondestructive (NDE) techniques

• Corrosion or fouling records

• Chemical analysis

This guideline uses the terms control parameters and diagnostic parameters. Controlparameters are parameters such as pH, corrosion inhibitor concentration, corrosionrates, and microbiological survey data that assist in the control of a chemical treatmentprogram and the operation of the FPS. These could have an immediate effect oncorrosion in the system. Diagnostic parameters provide “baseline” information that can



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alert the system chemistry reviewer to potential problems or be used to assist withtroubleshooting of problems.

6.2 Corrosion Monitoring Techniques

Corrosion in FPS most frequently occurs as general (lateral wall-thinning) corrosion orpitting corrosion occurring under deposits, at welds, or at stress-associated sites (forexample, threaded unions). Corrosion rates in FPSs are dependent on materials ofconstruction, fabrication methods, operation conditions, water chemistry, andmicrobiological factors. Each specific system is designed with an allowable wallthickness loss. However, it is generally accepted that a corrosion rate of > 3.0 mils peryear (mpy) (>0.08 mm per year or mm/y) on schedule 40 carbon steel is consideredexcessive. A corrosion rate of > 0.5 mpy (> 0.01 mm/y) on thin wall carbon steel(schedule 10) may also be considered excessive. Pitting corrosion is such a variablephenomenon that establishing an acceptable rate, or even accepting a procedure formeasuring a rate, remains a challenge. Criteria for acceptance or non-acceptance ofperformance in pitting control is based on whether pitting is occurring. The rate ofpitting corrosion is generally not a consideration.

Traditional corrosion monitoring techniques are based on using corrosion coupons, testspool pipe segments, or electrochemical measurement procedures.

6.2.1 Corrosion Coupons

Corrosion coupons are metal specimens made of the system metallurgy that arecarefully prepared, weighed, and inserted into the system at a point where they areexposed to the system water under conditions that simulate the operating conditions ofthe system (for example, stagnant or intermittent flow). They are exposed for a periodof time that is dependent on system operation, but for a period of not less than 90 days.After exposure, the coupons are removed, cleaned by specified procedures, and re-weighed to determine their weight loss. The weight loss is used to calculate a generalcorrosion rate.

The corrosion rate is expressed in units of mils per year (mpy) or millimeters per year(mm/y). Coupons can also be inspected for the presence of pits and pit depth.However, the absence of pits on the coupons does not necessarily mean absence ofpitting in the system.

Insertion of the coupons into the system is usually achieved by installing a side-streamcorrosion coupon rack constructed of noncorroding materials such as PVC.[5,6] Thelocation of the coupons should be arranged so that failure of the coupon will notobstruct FPS piping. Under optimized testing situations, coupons of differingmetallurgy should not be installed in the same rack. If only one rack is available,



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ferrous metals should be located upstream from nonferrous metals. For example, thesequence should be carbon steel and stainless steel, followed by copper alloys andother nonferrous materials.

Variations of the conventional corrosion coupon configuration include coupons withweld seams, stressed U-shaped coupons, and “sandwich coupons.” The latter are twocoupons clamped together, separated by an elastomeric gasket material to provideanaerobic inner surfaces. The extent of corrosion using sandwich coupons is measuredby making weight loss determinations, determining the amount of surface area on theinner surface that is involved with pitting, and measuring maximum pit depth.

Corrosion coupon techniques are relatively uncomplicated to use. The procedureprovides historical data that can be used for assessing the overall conditions related tothe potential for corrosion to occur. However, the corrosion rates measured should notbe considered as those that are occurring in the actual system. At best, the rates can beconsidered as a reproducible estimate of the relative corrosion rate occurring under agiven set of conditions.

6.2.2 Test Spool Pipe Segments

Performance monitoring by use of test spool pipe segments is based on installation ofpipe segments in the system, preferably at sites where corrosion has been foundpreviously. Installation is done to provide the capability of removing the pipe segmentsfrom the system in a design where the segment can be removed and examinedperiodically without requiring that the FPS be taken out of operation. This can be doneby making flanged installations at a point where an alternative bypass line can be putinto service as the test spool is removed for examination.

Test spool pipe segments can be “new” pipe or pipe removed from the system thatalready has shown signs of corrosion. Assessment of performance is based on visualinspection and other criteria used to compare the current condition of the pipe segmentto the previous inspection. This procedure is done over a relatively long time period;therefore, the use of photographs taken at the time of inspection is very useful.

The test spool technique is especially useful in performance monitoring the progress ofan on-line, long term, chemical treatment mitigation program. It also provides anexcellent site for collecting samples for microbiological fouling and chemical analysis.The data gathered are considered as historical data.

Although not specifically considered a corrosion performance monitoring technique,the use of test spool pipe segments provides specimens for examination by destructiveanalytical procedures when necessary. This is usually associated with root cause failureanalysis.



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6.2.3 Electrochemical Techniques

Adaptations of linear polarization (LP) and electrical resistance (ER) measurementtechniques can be used to monitor performance of corrosion control methods in FPSs.The LP measurements are based on the principle that a voltage impressed across theconductive interface boundary will result in a current flow that is directly proportionalto the corrosion occurring on the metal electrode surface at the time of measurement.

The metal electrode, installed on a probe, is made of the same material of constructionas the FPS and inserted into a section of pipe or into a bypass corrosion coupon rack.Available designs include models with two electrodes and three electrodes. Eithermodel has been used to give some indication of a pitting index. Data obtained by thethree electrode probe have been shown to be most able to correlate to actual pitting inthe system. Probes with electrodes that are flush with the piping wall are also availableand perhaps are more suited to use in an FPS. Results of the measurements areexpressed in units of mpy or mm/y.

Temperature and flow influence the corrosion rate measured by the probes. Therefore,it is necessary to take measurements used for comparative purposes under similaroperating conditions. FPSs with high fouling tendencies and low conductivity are notwell suited for using LP performance monitoring techniques.

ER measures the resistance of a section of wire that is in contact with the FPS water. Asthe wire corrodes, its cross-sectional area decreases, thus causing an increase inresistance. This increase in resistance is measured over time and calculated into acorrosion rate expressed in units of mpy or mm/y.

Both the LP and ER techniques provide data considered as real-time data.

Another electrochemical technique available includes probe devices to monitorcorrosion and biofouling.1,2 Suppliers of these instruments should be contacted forfurther information.

6.3 Fouling Monitoring Techniques

Fouling or siltation is the result of the deposition of solids being carried to low-flow orstagnant sites during periods when water is flowing in the FPS. Generally, this is aninfrequent event. Perhaps the greatest source of fouling materials in FPSs is the

1 ”POEM” Corrosion/Membrane Filtration Cells, CLI International, Inc., Houston, TX, USA.

2 Deposit Accumulation Test System “DATS” Unit, Bridges Scientific, Sandwich, MA, USA.



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production of corrosion byproducts within the system. Often, fouling is a processinvolved with the growth of slime-forming bacteria in the system.

There are no specific guidelines for the amount of fouling tolerated in FPSs. There areno conventional fouling monitoring techniques that would be readily adaptable for usein FPSs. Therefore, performance monitoring of fouling control methods is relegated tomaking indirect observations. These indirect observations include:

• Noting the loss of flow rate and increase of delta P.

• Determining the frequency and cause of FPS component malfunction duringmaintenance inspections.

• Determining whether component malfunctions such as valve failure, plugging ofpressure gauges, system operation controllers, etc., detected during maintenanceinspections, could be related to lack of fouling control.

• Performing visual inspection of stagnant and intermittent low-flow sites whenaccessible.

• Sampling periodic first-flush water from drop-legs, system drain points, and firehose standpipes to subjectively determine the amount and composition of sludgecollected at the discharge points.

• Examining the composition of materials deposited on surfaces of biofoulingmonitoring equipment. Examination should include chemical analysis andcomparing the ratio of organic to inorganic material in the deposits.

• Interpreting data obtained during microbiological monitoring related to thepresence of slime-forming bacteria and filamentous microorganisms to indicate thepotential for fouling.

Collectively, the observations suggested above should provide some idea as to whethera fouling problem potentially exists. These observations should be made at the samefrequency required for an effective maintenance inspection program. Unfortunately,these observations are subjective data and are historical in nature. In the absence ofreal-time and objective performance monitoring data, an engineering judgment of thecondition of the system must be made. When doing this, it must be recognized thatperformance monitoring of system fouling may provide results only after the foulingconditions have reached a potentially critical level.



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6.4 Microbiological Growth Monitoring Techniques

Monitoring the growth of microorganisms in the FPS is important because of the impactthat microorganisms have on corrosion and fouling in the system. Effective control ofMIC (prevention mode) can be achieved only when the growth of microorganisms ismaintained below a critical level. When that critical level is exceeded, control is lost,and most likely a mitigation program will be required. Effective performancemonitoring is essential in preventing the loss of microbiological control. Elements ofmicrobiological monitoring techniques include:

• Microbiological analysis of planktonic populations in the bulk water, includingmakeup water

• Analysis of sessile colonization

• Determination of aerobic tuberculation formation

The detailed test procedures for doing planktonic microbiological analysis, sessilecolonization analysis, and selective culturing to detect specific types of microorganismsare described in Section 8.

Typically, selective monitoring for specific types of bacteria associated with MIC orfouling does not require additional testing if the procedures for examining planktonicand sessile populations include selective isolation.

6.4.1 Planktonic Microbiological Analysis

Analysis of the FPS bulk water and the water used to maintain the required watervolume will not give a direct indication of the conditions related to existing MIC orbiofouling problems. The tests will indicate only the general microbiological conditionsof the bulk water. In many cases, however, bulk water analysis provides a reliableindication of general conditions of microbiological control trends. It may indicate that asignificant change in the microbiological macroenvironment has occurred that couldhave an effect on the microenvironment within the sessile colonization.

Unique to FPSs, samples should be taken from both stagnant sites and flowing siteswhen possible. Stagnant sites would include first flush water from drain lines, fire hosestandpipes, and maintenance inspection points. Flowing samples can be taken fromthese sites as well after flushing for approximately three minutes. Samples should betaken from as many sites in the system as possible. Sampling at least five sites locatedfrom the beginning of the system to the farthest point from the makeup source issuggested.



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Samples of the makeup water should be taken at the point where it is added to thesystem. If the system has a makeup storage water tank, samples should be taken at thedischarge of the tank. Makeup water samples should be taken in duplicate to minimizepotential sampling errors. Samples should be cultured in triplicate. Supplementalsampling at more frequent intervals may reduce the need for duplicate sampling andtriplicate culturing. Selective media should be used to detect the presence of thefollowing:

• Total aerobic bacteria

• Total anaerobic bacteria

• Sulfate-reducing bacteria

• Metal-oxidizing bacteria

• Acid-producing bacteria

• Slime-forming bacteria

A variety of test kits are available that can be used to determine the presence andrelative numbers of these bacteria. A description of the selective media and theculturing procedures used for these tests, when test kits are not used, is provided inSection 8.

The data obtained from bulk water analysis must be interpreted on a trending basis.Significant differences are those that are at least 2 orders of magnitude, for example, achange from 1 x 103 to 1 x 105. Replications should agree to 1 order of magnitude.

Microbiological analysis of the bulk water should be done at a frequency of at leastonce every six months. In systems where there has been MIC or fouling in the past, thefrequency should be at least once every three months for a year.

6.4.2 Microbiological Analysis of Sessile Colonization

The formation of sessile colonies on surfaces within the FPS is generally of moreconcern than the planktonic populations. However, performance monitoring of sessilepopulations is more complicated than planktonic analysis. The major difficulty is accessto the sites where sessile colonies form in the system. To overcome this difficulty,installation of strategically located biofouling monitors can be used. There are severaldesigns of biofouling monitoring devices. The basic similarity is that an accessiblesurface is provided that is ideally suited for microbiological colonization to occur.Conventional biofouling monitors can be adapted for use in FPSs operated understagnant flow conditions. Screened coupons, similar to corrosion coupons, can be



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inserted into a corrosion coupon rack, when available. Holders containing several smallbeads made from system materials can be inserted in to the system, usually at a waterdischarge point. The beads provide a site for sessile colonization. More sophisticatedmonitoring devices can be adapted for FPS use 3,4monitor but are usually not required.Biofouling monitors based on measuring ∆-temperature or ∆-pressure are not readilyadapted for use in FPSs.

With each of these biofouling monitors, it is necessary to retrieve the sessile growthsurface and remove the biomass for analysis. In some cases, the performancemonitoring is based on quanitizing the mass or weight of biomass that has accumulatedon the test surface. In other cases, it is based on the population density ofmicroorganisms per unit of surface area. The values obtained from microbiologicalanalysis of sessile colonization are generally expected to be greater than those obtainedfrom planktonic monitoring.

The Swab Sampling and Culturing Procedure described in Section 8 can be used toremove and culture the biomass. It simply involves wiping the test surface with asterile swab and directly culturing the material collected on the swab. Typical siteswhere swab sampling can be used include test surfaces of biofouling monitors or atsystem water sample points. When accessible, test spool pipe segments and the surfaceof corrosion coupons can be used. The samples are cultured on the selective mediadiscussed with testing planktonic samples. Quantitative results can be obtained byusing dilution end-point procedures. Other methods to remove the sessile biomassinclude scraping or ultrasonic removal.

The frequency of sessile colonization performance monitoring is system specific anddepends on system operating conditions. However, it is suggested that tests be done atleast once every three months. The results from these tests are interpreted on a trendingbasis.

6.4.3 Tuberculation Analysis

Performance monitoring of the extent of tubercle formation on system piping surfacesis an indirect monitoring procedure. However, it is a very important condition tomonitor because of the impact that tuberculation has on FPS flowrates in small ID pipe,MIC, and underdeposit pitting corrosion.

3 ”CorrDats” Unit, Bridges Scientific, Sandwich, MA, USA.

4 ”BIo-George Monitor” Structural Integrity Association, San Jose, CA, USA.



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Monitoring must be done by visual inspection. Documentation is important and can bein the form of written description and photographs. Sections of small ID pipe (< 2.0inches [< 5 cm]) should be removed and inspected for degree of blockage and tubercleformation. The installation of test spool pipe segments discussed earlier is a distinctadvantage for this type of monitoring. Samples of the tubercles can be collected whenthe system is opened. Samples should be examined immediately using microscopictechniques, as described in Section 8, to confirm that metal-oxidizing bacteria such asGallionella sp. are responsible for the formation of the tubercles. Surfaces under thetubercle can be examined to detect pitting caused by SRB or underdeposit pittingmechanisms.

It is suggested that tuberculation analysis be done at least annually or as often as thesystem is opened.

6.5 Other Performance Monitoring Techniques

6.5.1 Internal Visual Inspection

Visual inspection is an important tool in performance monitoring. Visual inspection ofthe internal sites of the FPS should be made at every opportunity. Inspection techniquesmay include boroscope inspection and remotely operated video equipment. Internalvisual inspection should include documentation of the observations made.

6.5.2 Nondestructive Evaluations

A number of mechanical/electronic techniques have been adapted for use as on-linemonitoring of FPSs. Two of these techniques that have been employed with somedegree of usefulness are ultrasonic testing (UT) and radiographic testing (RT). UT and RTare labor intensive and expensive, which limits their use as a performance monitoringmethod in FPSs.

UT is a nondestructive method for characterizing wall thinning of piping. The tests canbe made from the outside of the pipe so they can be done without taking the FPS out ofservice. UT testing may be useful in detecting localized corrosion when adequateinspection locations are selected and inspection grids are sufficiently fine. Slight wallthickness losses are difficult to detect by UT. A major advantage of UT is that thesystem does not have to be drained. A major disadvantage is that geometricdiscontinuities, such as welds or the presence of tuberculation, require specializedinterpretation that must be confirmed by visual inspection at some point in time.

RT consists of penetrating the component (piping) with ionizing radiation andcapturing an image on a film similar to an X-ray or on an electronic sensor similar to a



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video screen. Typically, RT requires that the component be drained. Although notwidely used in FPSs, in certain cases, RT nondestructive examination may haveapplication as a performance monitoring technique. A relatively recent report has beenmade in the literature [7] concerning NDE procedures for monitoring corrosion oninternal surfaces of carbon steel storage tanks, pressure vessels, and large and small ODpiping. The technology is based on low-frequency electromagnetic technique (LFET)measured on the OD surface of the component.

6.6 Corrosion or Fouling/Leaks Performance Tabulation

The tabulation of the frequency and location of corrosion or fouling conditions such asthe occurrence of leaks is not considered a specific procedure to be done as aperformance monitoring activity. However, tabulation of these observations as theyoccur provides an important insight as to the condition of the FPS and the performanceof the treatment program being used to control or mitigate corrosion and fouling.Generally, the inspection for leaks or other corrosion or fouling conditions is part of themaintenance inspection procedures discussed in Section 2. It is discussed here becausethe information provided by these inspections should be used to interpret dataobtained from several of the other elements included in the performance monitoringprogram.

Inspection for corrosion or fouling is usually done by visually inspecting the piping,valve connections, threaded unions, weld seams, etc. When the system is beinginspected for leaks, it may not be necessary to actually observe water leaking from thecomponent. Evidence of deposits accumulating on the exterior surface of the pipe oraround joints, flanges, or welds can be sufficient to indicate that leaks are present orhave occurred earlier. If patches or spots of paint failure are observed and a spot ofsurface rust exists on the pipe exterior where the paint has flaked off, it is probable thata pit, close to the point of through-wall penetration, exists on the interior surface of thepiping.

Other observations that should be included in the tabulation of corrosion or foulingconditions include loss of FPS water pressure, observed by recording pressure gaugereadings, observing the amount and frequency of makeup water addition andfrequency of jockey pump operation. When the addition of makeup water to the systemis excessive or a chronic pressure loss cannot be rationalized by system operation, itmay be likely that leaks are occurring at a point such as in buried lines.

6.7 Chemical Analysis Performance Monitoring Criteria

The primary purpose of chemical treatment of FPS water is to prevent corrosion andfouling in order to maintain the system in a constant functional status for its design lifespan. The specific treatment program is based on the chemical characteristics of the FPS



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water when the treatment was made. If the chemistry of the water changes at somepoint after treatment is made, it is possible the treatment program is no longerappropriate, and adjustments may be necessary to ensure that performancespecifications are being met. Chemical analysis of the treated water in the FPS isnecessary to detect if chemical changes have occurred and if adjustments are required.Chemical and physical criteria to be tested should include:

• pH

• Conductivity

• Presence of H2S or suspended metal sulfides (smells like rotten eggs)

• Qualitative appearance of FPS water, which might include changes in color andturbitity

• Concentration of treatment chemicals

In most cases, the performance of the treatment chemicals is related to the initialconcentrations added to the system and the residual concentrations in the FPS waterafter a period of time. To ensure that the treatment specifications have been met,chemical analysis of the FPS water should be done immediately after treatment and ona routine basis following the treatment period. The analyses required are the initialconcentrations and the subsequent residual concentrations of the treatment chemicals. Itshould be noted that it may not be possible to measure residual concentrations of somechemicals in FPS water. In this case, it may be necessary to use indirect analyticalprocedures. Analytical procedures for some of the specialty treatment chemicals, suchas certain types of biocide/biostats/and corrosion inhibitors, should be provided byvendors.

6.8 Data Trending

Performance monitoring is the gathering of both historical data and real-time data asdiscussed earlier. The tabulation and trending of both types of data are important partsof performance monitoring. The data to be trended depend on the system design,treatment program, system operation, and the monitoring procedures being used.Trending data should be focused on control parameters, diagnostic parameters, andsystem performance. The purpose of the trending is to detect and often to anticipatecorrosion or fouling. Therefore, an important part of trending is to use the dataobtained. They should not be tabulated, then put into some storage facility, andperhaps reviewed later only when a corrosion or fouling event occurs. Computer datalogging and spreadsheet diagnostic software programs have been developed tofacilitate and enhance the value of trending performance monitoring data.


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7 REFERENCES

1. Recommended Cleaning Practices for Service Water Systems, EPRI, Palo Alto, CA:December 1997. Report TR-108923.

2. R.W. Lutey and G. Lozier, “On-line Chemical Cleaning for Once-Through ServiceWater Systems,” presented at the EPRI SWS Corrosion Seminar, Clearwater Beach,FL (April 1992).

3. Handbook of Biocides and Preservative Use. H.W. Rossmoore, ed., Chapman & Hall,New York, NY 1995. Chapter 3.

4. “Enzyme Technology: A Tool for the Prevention and Mitigation of MIC,” Paper No.97-71, presented at the International Water Conference, Pittsburgh, PA (October1997).

5. Cooling Water Treatment Manual. 3rd Edition, Section 5, National Association ofCorrosion Engineers International, Houston,TX. TPC Publication No. 1.

6. Standard Method for Conducting Coupon Tests in Plant Equipment. ASTM, Philadelphia,PA. ASTM G4-84.

7. S. Ramchandran, “OD Pipe Scanning Using Electromagnetic Technique for InternalFlaw Evaluations,” presented at the EPRI Service Water System ImprovementSeminar, EPRI NDE Center, Charlotte, NC (June 1998).

8. H. H. Uhlig, Corrosion and Corrosion Control. John Wiley & Sons, Inc., New York, NY,Fourth Printing, 1967. P. 58.


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8 APPENDIX A: MICROBIOLOGICAL SURVEY

PROCEDURES

I. Background

The microbiological survey procedures discussed in this appendix are an assembly ofprocedures taken from numerous sources including those published by the AmericanSociety of Testing Methods, American Petroleum Institute, National Association ofCorrosion Engineers (NACE) International, American Water Works Association,Society of Industrial Microbiology, and the American Society of Microbiology. Many ofthese procedures have been modified and revised to meet the needs and requirementsof surveying microbiological conditions in industrial water systems such as FPSs. Theyare not intended to be considered as “standard methods” that comply with any specificquality assurance specifications. They are provided simply as proven guidelines, basedon industry experience, to assist the plant in the evaluation and treatment of corrosionand fouling in fire protection systems.

On-Site Visual Examination of Accessible Components

This is usually done during an outage or when a specific component is taken out ofservice. The latter may be associated with a maintenance shutdown or with an off-lineinspection/performance testing of redundant components. Timing these examinationswith the cooperation of operations and maintenance personnel is very important. It isalso very important to make the visual examinations and collect water samplesimmediately as the system is taken out of service.

Color photographs are made of the sites inspected to provide documentation of theconditions observed. Very often, the visual inspection is concurrent to other NDE tests,such as eddy current and ultrasonic measurement. The NDE tests may be done byutility personnel or outside subcontractors.

Visual inspection of the internal surfaces of the FPS is done by using a pneumatic 360°video boroscope. The video probe is attached to a VCR so that the conditions found


Appendix A: Microbiological Survey Procedures

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inside the system can be recorded. Color photographs are made from the views shownon the video monitor.

As the visual examinations are made, samples of water and deposits are collected at thevarious sites inspected. Swab samples are taken from the wetted surfaces andsubsequently cultured on selective media discussed later. Microbiological analyses andchemical analyses are made on samples collected during the visual inspection.

On-Site Microscopic Examination

Samples of deposits, residual corrosion products including tuberculation, and biomasscollected from the surfaces of the accessible wetted surfaces are examinedmicroscopically. A compound light microscope at 1000 X with selective microbiologicalstains are used to characterize the composition of the deposits. Selected slidepreparations are used to provide photomicrographs of microorganisms potentiallyinvolved with MIC.

On-Site Microbiological Culture Tests

Microbiological culturing tests should be made on-site immediately as the samples arecollected from the accessible wetted surfaces. Cultures are made from swabs anddeposits. Selective media culturing procedures are used to isolate microorganismsassociated with MIC and fouling. The selective media include:

Cetrimide medium for Pseudomonads and slime-forming, metal-oxidizingbacilli and cocci (SMOB)

TGEA medium for slime-forming bacteria (SFB)

API medium for sulfate-reducing bacteria (SRB)

Gallionella medium for iron-oxidizing bacteria (IOB)

Nitrate medium for ammonia-producing bacteria (AMP)

Nitrite medium for selective acid-producing bacteria (NPB)

Enriched Clostridia medium for hydrogen- or acid-producing anaerobic bacteria(APB)

NOTE: Other medium and culturing procedures may be done, based on theneeds identified by microscopic examination of the deposits or other means.



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The selective growth media suggested here are to be considered generic formulas forthe selective isolation of the types of microorganisms listed. Other media formulationsmay be used as alternatives when it has been established that the alternate formulationwill do the same selective cultivation.

A number of commercially available “field test kits” have been developed for use inconducting on-site microbiological surveys. Some have the capabilities of detecting andenumerating the microorganisms for which the selective growth media are used. A listof these test kits is provided later in this document.

Deposits and Metallurgical Analysis

Chemical analysis is made of the residual corrosion products and deposits found at thecorrosion sites. Analysis of the deposits includes both organic and inorganiccomposition. Metallurgical examination is a destructive failure analysis to determinethe mechanism of component failure. Analytical procedures include:

Procedure Acronym

Fourier transformed infrared FTIR

Infrared spectrometry IR

Gas chromatography GC

Liquid chromatography LC

High performance liquid chromatography HPLC

Inductive coupled plasma ICP

Scanning electron microscope energy dispersive x-ray SEM-EDX

Organic deposit analysis

• Direct analysis by FTIR

• Solvent extraction by IR, GC, LC, HPLC

Inorganic deposit analysis

• Direct analysis by wet chemistry procedures or ICP

• Ash analysis by ICP



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Specific anion detection

• Direct analysis by SEM-EDX or wet chemistry procedures for chlorides, sulfides,and phosphides, etc.

Metallurgical analysis

• Destructive procedures to determine failure mechanism of component by ICP, SEM-EDX and x-ray radiography

NOTE: The extent of metallurgical failure analysis is determined by the availability ofspecimens and the data required to determine the root cause of the failure.

Water Chemistry Analysis

Samples of the bulk water are routinely analyzed using standard water analysismethods. Criteria to be tested should be established and a list attached to appropriatereporting documents.

Report of Observations and Results

The observations made during the survey, as well as the results of the various testsdone both on-site and in the laboratory, are used to present an interpretation of thesituation, for example, probable potential for MIC or the root cause of the componentfailure. The discussion provides a basis for further action and the development of aprogram for the prevention and/or the mitigation of an existing MIC situation.

II. Description of Test Procedures

Microscope

Objective - To describe the type, function, and care of the compound microscope.

Type - The bright-field compound microscope can be used both on-site and in thelaboratory. Table 8-1 provides the recommended optical specifications.



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Table 8-1Optical Specifications

NumericalAperture

Total (N.A.)Common

NameObjective

MagnificationEyepiece

MagnificationTotal

Magnification

0.09 Scanner 4X 10X 40X

0.25 Low Dry 10X 10X 100X

0.65 High Dry 40X 10X 400X

1.25 Oil Immersion 100X 10X 1000X

It is important that the resolving power of the microscope be checked at allmagnifications by observing stained objects of an approximate known size. Forexample, fungi should be easily distinguished at about 100X, large bacteria at 400–500X, and small bacteria should be satisfactorily resolved at 950–1000X (oil immersion).

Function - The microscope is composed of three optical systems and a light source;each of the systems contributes to the final resolving capacity of the microscope and hasa primary function that is complemented by each of the other systems. The mainfunctions of each part of the optical system of the bright-field microscope are outlinedbelow:

1. Objective lens

a. To gather light coming from any part of the object

b. To unite this light in a point of the image

c. To form the image at such a distance that magnification is obtained

2. Eyepiece (Ocular Lens)

a. To form on the retina a real image of the actual image from the objective,sometimes referred to as a “virtual image”

b. To magnify the real image formed by the objective

c. To image ocular micrometry devices, pointers, etc., which are located inthe eyepiece



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3. Condenser

a. To concentrate light upon the object and increase the brilliancy of theimage

b. To furnish oblique dark-field illumination where applicable

4. Illuminator

To furnish a visible light source

Care - The microscope represents a considerable investment and, with proper care,should function satisfactorily for many years. A microscope is useful only when it isworking properly. Some of the primary considerations in care and maintenance of themicroscope are as follows:

1. Objective Lens

a. Avoid making contact with the slide by first focusing at lowmagnification (10X) on a prominent object in the field with the coarseadjuster and then focusing with the fine adjuster until the desired detail isfound. This prevents the objective from touching the slide.

b. Guard against corrosive chemicals, acid and alkaline fumes, extreme heatand cold, and mechanical shock. Optical glass and coated lenses are verysusceptible to surface alteration.

c. When cleaning the objective lens, use a soft, long-fibered paper, especiallymade for cleaning lenses. Do not use paper with abrasive fillers or dirtylens paper. If dust is on the lens, dampen the lens paper with distilledwater and wipe softly, then follow with a dry sheet of clean lens paper.

d. When observing materials in which contact is made with the objective orin which fumes evolve, wash the lens with distilled water, wash it withxylene (alcohol should not be used), and dry it. Immersion oil should beremoved from the objective immediately after completion of theexamination.

e. Keep objectives and eyepieces in place at all times except when preparingthe microscope for shipment.

f. Clean only the exposed surfaces of the objective lens. The interior surfacesof the lenses are well protected and should remain free from dirt or fogwith typical use.



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2. Eyepieces

It may be necessary to clean the interior surfaces of the eyepiece lens. However,extreme caution should be taken to avoid contamination and breakage duringdisassembly and assembly. Cleaning should be done with a clean lens paper anda camel hair brush.

3. Condenser

Dust and scratches on the top surface of the condenser lens are particularlyobjectionable because they may interfere with viewing of the specimen.Therefore, the same diligent care should be given to the condenser lens as to theother optical systems of the microscope. The condenser lens should be protectedfrom dust and corrosive materials. When immersion oil is used, remove the oilimmediately after completion of the examination.

4. Illuminator

a. When a bulb is to be replaced in the direct-illuminator type, effortsshould be made to obtain a bulb similar to that specified for theilluminator. Resolution can be significantly impaired by an improper lightsource.

b. If a reflecting mirror is used, the surface should be kept free of dust andscratches.

Water Suspension Slide Mount Technique

Objective: To describe the method of mounting water-suspended specimens that canbe resolved without the assistance of microbiological stains.

Suspension Technique: This technique is applicable to the detection of algar, protozoa,helminths, plant parts, etc., and some bacteria such as Gallionella and Desulfovibrio (oftenfound in fresh water).

1. Materials

a. Apparatus

1. Microscope slides

2. Cover glasses

3. Medicine dropper



8-8

4. Dissecting needles

5. Petri dish

b. Mounting medium

Permount

2. Procedure

a. Place one drop of the water-suspended sample on the microscope slide.When examining a dehydrated specimen or a nonaqueous deposit,disintegrate it in water with dissecting needles. Allow it to soak for about10 minutes prior to transfer to the slide.

b. Place a clean cover glass over the specimen, and press as close to the slideas possible. Avoid air bubbles. If the specimen is bulky, Gurr’s W. M.Medium can be used. When the cover glass has been properly placed, theslide is ready for microscopic examination.

Comments

The preparation of wet mounts is appropriate to microscopic examination of depositscontaining both microbiological and non-microbiological materials. Many deposits thatdevelop in aqueous systems are easily adapted to the wet-mount technique. One of themost common faults in the preparation of microscope slides is applying too muchsample to the slide. The amount of sample needed to obtain a reliable diagnosis is nolarger than a pinhead.

When deposits are composed of several types of stable agglomerates, it is importantthat a separate slide be prepared for each type.

Hanging-Drop Slide Mounts

Objective: To describe the hanging-drop technique and its application to microscopy.

The hanging-drop technique permits microscopic examination of living micro-organisms suspended in a fluid. This provides the advantage of observingmicroorganisms without distorting their morphological characteristics. One use of thistechnique is the observation of motility, which is not apparent when using the “simplestaining” technique. This technique is also applicable to microscopic examination ofsulfate-reducing bacteria and “iron” bacteria in scale-like deposits.



8-9

1. Materials

a. Apparatus

1. Deep-well slide

2. Cover glass

. Medicine dropper

b. Sealing materials

Vaseline or stopcock grease

2. Procedure

a. Rim the edge of the depression in the deep-well slide with a thin layer ofsealing material.

b. Place a small drop of the liquid containing the specimen to be examinedin the center of a cover glass that is positioned on a flat surface.

c. Invert the deep-well slide, and position it over the cover glass so that thedrop of liquid is directly in the center of the well.

d. Press the deep-well slide firmly onto the cover glass.

e. With a quick, smooth motion, invert the slide. If this step is performedproperly, a hanging drop will be formed on the cover glass.

f. The slide is now ready for microscopic examination.

CAUTION: Always begin observations on the low (10X) objective, and manipulatecarefully when changing to a higher magnification. The objective lens can be severelyscratched if the nosepiece is positioned too closely to the slide when changing to ahigher magnification. NEVER use the oil immersion lens when viewing a hanging-dropslide.

Comments

When determining motility by the hanging-drop technique, care should be taken not toconfuse microorganism motility with Brownian movement. Brownian movement is anirregular vibrating movement of suspended matter that remains relatively stationary inthe field; whereas, true motility is demonstrated by the ability of suspendedmicroorganisms to traverse a relatively stationary field.



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When hanging-drop mounts are examined with the bright-field microscope, it isextremely important to adjust the light source (by closing the diaphragm or loweringthe condenser) so that the maximum contrast of the image can be obtained.

Staining Procedures

Objectives: To determine and demonstrate the use of basic biological stains, as well asthose specific stains for spores, capsules, and slime layers.

Simple Stains

The term “simple staining” refers to the preparation of biological material forexamination by using only one stain to obtain the desired effect.

Clean slides are required for preparing satisfactorily stained mounts. New slidesshould be handled only by the edges and polished with a piece of lens paper. Usedslides should be cleaned with detergent, rinsed with water, then with alcohol, anddried.

1. Materials

a. Apparatus


2. Cover glasses

3. Petri dish


5. Absorbent paper

6. 70% ethanol

7. Permount

b. Stains

1. Lactofuchsin

Acid fuchsin (dye content 57%) 0.1 gram lactic acid (85% reagentgrade) 99.9 grams



8-11

After mixing, allow to stand overnight and filter. This stain should bereplaced after six months.

2. Crystal violet

Crystal violet (dye content 95%) 0.2 grams

Distilled water 88.8 grams

Dissolve dye in water.

2. Procedure

a. Lactofuchsin stain

1. Place a drop of water on the slide. If the sample is free of debris or isa smear from a pure culture, disperse it gently in the water on theslide. If the sample is bulky, disperse it by teasing with a dissectingneedle in water in a petri dish or water glass. Transfer a small portionof the specimen to the slide.

2. After the specimen is dispersed properly on the slide, add a drop oflactofuchsin stain. Mix the stain with a specimen. Heat gently toincrease the intensity of the stain. Use a drop of Permount instead ofwater on the slide when excessive debris (fiber, filler, scale, etc.) ispresent in the specimen.

3. Place a cover glass over the specimen, and gently press until theexcess liquid and air bubbles are expelled from beneath the coverglass.

4. Carefully take up the excess liquid with a dry, absorbent paper whilethe cover glass is pressed downward. If this step is not executed withcaution, the cover glass can become soiled, and reduction inresolution can result.

b. Crystal violet stain

1. Proceed as in a. (1).

2. After the specimen is dispersed uniformly on the slide, add a drop ofcrystal violet stain. Mix the stain with the specimen, and place a coverglass on the specimen as outlined in a. (3) and a. (4).



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Comments

Lactofuchsin - This stain is suitable for the initial microscopic examination ofmicrobiological deposits. It is specific for microorganisms and can be used withoutexcessive interference from nonmicrobiological materials in the sample, such as fibers,organic materials, fillers, etc. Lactofuchsin stains microorganisms a red-to-pink color.The color intensity is not great, so care must be taken to examine the preparationthoroughly. Heat lightly, if required, to increase the intensity.

Crystal violet - This stain is a general purpose stain that gives a deep violet color. It isnot specific for microorganisms. The stain is excellent when morphologicalcharacteristics of the specimen are desired.

Differential Stains for Endospores

Spores are highly refractile bodies of certain bacteria and are considered a resting stageor protective stage in the life cycle. Spores may indicate that the population hasresponded to unfavorable environmental conditions, such as exhaustion of nutrients,the presence of metabolic waste products, or the presence of certain toxins.

Spores resist staining, which suggests two ways to detect them. Spores appear as clear,round or oval, refractile unstained bodies surrounded by stained bacteria. Tosubstantiate this observation, a specific staining technique for bacterial spores shouldbe used.

1. Materials

a. Apparatus

1. Clean microscope slide

2. Alcohol burner or equivalent

3. Transfer needle

4. Forceps

b. Stains

1. Malachite green

Malachite green (certified) 5.0 grams

Distilled water 95.0 ml.



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2. Safranine

Safranine 0 (2.5% in ethyl alcohol) 10.0 ml.

Distilled water 100.00 ml.

2. Procedure

a. Make a thin water suspension of the specimen on a microscope slide andallow to dry; heat gently to fix the sample to the slide.

b. Flood the slide with malachite green.

c. Heat the stain on the slide to steaming, but not boiling, for two to fiveminutes.

d. Wash gently in tap water until no more color is removed from the slide.Since malachite green is readily soluble in water, this washing shouldremove all color except that which has been occluded within the bacterialspore.

e. Flood the slide with safranine, and allow to stain one minute.

f. Wash the slide gently in tap water, and carefully blot dry.

g. Examine the slide under oil immersion. Spores will appear green, ascontrasted to the nonspore vegetative cells, which appear pink.

Comments

Other differential staining techniques have proven useful for examination ofmicrobiological deposits. These include the Gram stain, acid-fast stain, flagella stain,stain for droplets, and several differential staining procedures used to distinguishspecific types of microorganisms.

Capsule Stain

1. Materials

a. Apparatus

1. Microscopic slides

2. Inoculating loop



8-14

b. Reagents

1. Capsule stain 1

2. Capsule stain 2

2. Procedure

a. Flame one side of the slide in the flame of a Bunsen burner to remove anyoil or grease. Allow the slide to cool.

b. Place a drop of 1% congo red solution (capsule staining solution 1) in thecenter of the slide with an inoculating loop.

c. Transfer some of the bacteria to be used from the culture to the drop ofcongo red solution on the slide. Mix.

d. Spread the drop of congo red solution containing the bacteria out over theslide with your inoculating loop to form a thin smear about the size of anickel. Allow the smear to air dry. Do not heat fix the smear.

e. Cover the dried smear with capsule staining solution 2. Allow this solutionto remain in contact with the smear for two to three minutes.

f. Pour off the capsule staining solution 2, rinse the slide in gently runningwater, and carefully blot the slide dry.

g. Examine the slide under the oil immersion lens of the microscope. Thebackground will stain a grayish color. The bacteria cells will stain red. Thecapsule, if one is present, will not stain and will appear as an unstainedhalo around the cells.

Dry-Mount Films

The preparation of specimens in dry-mount films is necessary for microscopicexamination when using certain “simple” and differential staining procedures. Dry-mount films are best suited for the examination of bacteria because they are able towithstand the drying better than are other microorganisms, such as filamentous fungiand yeasts.

1. Materials

a. Apparatus




8-15

2. Cover glasses


4. Medicine dropper


b. Reagents

50% aqueous ethanol

2. Procedure

a. Transfer a small portion of the specimen to a slide, and disperse evenly ina drop of water.

b. If not already a liquid, mix the specimen with water or 50% ethanol.

c. Spread the liquid suspension of the specimen thinly over the surface ofthe slide, and dry gently over an alcohol burner or other heat source.

d. If a concentrated film of the specimen is required, add several drops ofthe liquid suspension of the specimen successively with a medicinedropper to the surface of the slide, allowing each drop to dry beforeadding the next drop on top of it.

Semi-Permanent Slide Mounts

This technique involves the use of Permount or a suitable alternative. Permount issoluble in water and is useful in the preparation of permanent slides of specimens suchas fungal colonies and other plugging and fouling microbiological deposits.

1. Materials

a. Apparatus


2. Cover glasses


4. Absorbent paper



8-16


2. Procedure

a. Place a drop of Permount on the specimen, which has been prepared andreadied for wet or dry mounting.

b. Carefully place a cover glass on the preparation without trapping airbubbles.

c. Remove any excess medium by carefully blotting with absorbent paper.Allow to dry for 10 minutes.

Comments

The use of Permount is recommended for the examination of materials that containsignificant amounts of silt, corrosion products, scale, etc., which tend to reduceresolution and cause air bubbles to develop.

Swab Sampling for Culturing from Deposits and Surfaces

Objective: To describe the method for collection of samples of sessile biomass and thetransport of those samples to a site for subsequent microbiological analysis.

This procedure provides a fast, easy-to-use system for standardizing the collection andtransport of microbiological samples composed of aerobic and anaerobic bacteria,fungi, and algae. It reduces the chance of contamination and breakage in transit. Itprovides a simple means for removing and collecting biomass/biofilm from componentsurfaces. Specimens stay moist and, in most cases, viable for up to 72 hours.

1. Materials

a. Sampling Apparatus

1. Aerobic samples

Precision Dynamics Culture (C.A.T.S.)*

* The indicated materials are typically available from local biological supply vendors. BBL is owned byBecton Dickinson Co., a worldwide supplier of microbiological laboratory materials and equipment.Edge Biologicals, located in Memphis, TN, is a supplier of microbiological laboratory materials thatcustom manufactures and supplies items in compliance with specifications provided.



8-17

The C.A.T.S. culture tubes feature an all-plastic tube with modifiedAimes transport medium contained in a sealed chamber in thebottom of the tube. Each collection swab consists of a plastic shaftwith a rayon tip, firmly secured to a high-density polyethylene cap.The culture tube is bias cut for easy insertion of the swab. A controlnumber and expiration date are clearly printed on the outerpackage. Shelf-life of the C.A.T.S. is up to two years when storedbelow 30°C.

The double C.A.T.S. system (two swabs per tube) is recommendedwhen the sample collection is to be used for multiplemicrobiological analyses.

2. Anaerobic Samples

BBL Anaerobic Culturette Systems

The Culturette System contains one swab, two polyester pledgets,prereduced Cary-Blair transport medium, and a gas-generatingsystem. The tube is encased in a clear plastic, gas-impermeable,polyethylene bag environmental chamber. The tough outer wrapprotects the entire system and maintains sterility of the innercontents. Shelf life of the Anaerobic Culturette System is up to twoyears when stored below 30°C.

The anaerobic samples will be cultured under anaerobicconditions, as discussed later. These require equipment specificallydesigned to use for anaerobic procedures. Several options areavailable. These include:

BBL Gas-Generating Pouch Systems*

BBL “Bio-Bag” Environmental Chamber*

BBL GasPak 150 System*

b. Culture media

1. Aerobic

Gallionella media

(agar tubes with media solution overlay

Iron-oxidizing bacteria

Cetrimide agar (agar plates) Slime-forming bacteria

Tryptose glucose extract agar (TGEA)* Other slime formers



8-18

(agar plates) (nonselective)

Nutrient agar* (agar plates) Total aerobic bacteria

Nitrate broth* (broth tube) Nitrate bacteria

Nitrite broth* (broth tubes) Nitrite bacteria

Sabouraud dextrose agar* (agar plates) Fungi

2. Anaerobic

API media Sulfate-reducing bacteria

Thioglycollate medium* (broth tubes) Total anaerobic bacteria

Anaerobic agar* (agar plates) Total anaerobic bacteria

Reinforced clostridial agar*

(semi-solid agar vials/tubes)

Clostridial bacteria

2. Procedures

a. Sampling

Sampling sites must be selected to obtain representative samples. Ideally,the sites should be swabbed immediately after draining or while thecomponent surfaces are still moist. When sampling sites that areassociated with the accumulation of sludge and/or substantial amounts ofbiofouling, swabs should be made of both the outer surfaces and the innermass of the fouling material. The latter is done by plunging the swab intothe fouling material and swirling the swab at least 10 times beforeretracting the swab.

If the sample sites become accessible only after the surfaces have dried, itis necessary to rewet the surfaces with a minimum quantity of sterilewater and then wipe the surface with the swab. In some cases, it is moreconvenient to prewet the swab with sterile water and then wipe the drysurface.

In obviously aerobic environments, it is necessary to sample only foraerobic samples. However, it is recommended to use both aerobic andanaerobic sampling swabs for most situations. Unless multiple samplingsites at relatively similar environments will be done, it is recommendedthat replicated samples be taken. Individual swabs can be used to makemore than one isolation culture. However, when it is known that acomplete microbiological culturing will be done, it is recommended thatthe double-swab aerobic system be used for each site sampled. Double-swab anaerobic systems are not available.



8-19

Specific instructions for use of each of the swab systems are printed on theouter wrappings. Other “hints” include trying to minimize theaccumulation of dirt, mud, and other non-biomass material on the swabs.If sampling surfaces underneath tubercles, usually black in color, be sureto get some of the black material on the swab. When sampling surfaces oftubercles and corrosion products, be sure to get some of the yellow-orange, red-orange materials on the swab. Be sure to saturate the swab tipwhen wiping wet surfaces without any apparent fouling on them. Onsurfaces that are coated with a film of biomass, wipe the swab onto thesurface of the base material and thoroughly saturate with the biomass.

Immediately after making the swab sampling, return the swab/cap to thetube and follow the instructions for transport. Be sure that the tip of theswab is in contact with the transport medium contained in the bottom ofthe tube. Microbiological culturing should be done as soon as possibleafter sampling (ideally within 24 hours and no later than 72 hours).Refrigeration of the swab samples during transportation is typically notnecessary as long as the sample is not exposed to extreme temperatures,for example, greater than 50°C for more than 12 hours.

b. Culturing

The aerobic culturing procedures should be done first.

The first of these should be the streak cultures on agar plates of theselective media listed previously.

1. Aerobic streak plates

The agar plate (cover removed) is held with the surface in a verticalposition with one hand. With the swab in the other hand, the tip ofthe swab is spread in parallel streaks three or four times across thesurface of the agar, slowly rotating the shaft of the swab with thefingers. The direction of the streaks should be changed three orfour times by rotating the dish during streaking. This manipulationaccomplishes a thinning out of the microorganisms on the surfaceof the agar. When the streaking is properly performed, themicroorganisms will be sufficiently far apart in some areas of theplate that the colonies which develop on the surface of the agar willbe the progeny of isolated cells.

Transfers from the individual colonies can be examinedmicroscopically and subcultured for further identification andcharacterization.



8-20

2. Aerobic broth cultures

Duplicate swabs and/or the swabs used to make the streak platecultures can be used for broth culture procedures. The swabs areremoved from the transport tubes and inserted into the brothtubes. The shaft of the swab should be swirled at least 10 timeswhile the tip is immersed in the broth. If the swab is not to be usedfor further culturing, the tip of the swab should be left in theGallionella Culture medium.

The aerobic broth culture tubes should be loosely capped duringincubation. Growth of the microorganisms will appear as biomasson the walls of the tube, as a sediment on the bottom of the tube, oras a turbid suspension on the broth. The growth can besubsequently subcultured and microscopically examined forfurther identification and characterization.

3. Anaerobic streak cultures

Anaerobic streak cultures are made with the swab samples takenand transported using the Anaerobic Culturette System. Thestreaking/plating procedure is exactly as described for aerobicagar plate culturing.

Immediately after streaking, the plates are inserted into theanaerobic growth chamber, for example, Gas-Generating Pouch,“Bio-Bag” Environmental Chamber, or the GasPak System, andincubated at the appropriate temperature.

The isolated colonies that develop on the agar surface can besubcultured and examined microscopically for furtheridentification and characterization.

4. Anaerobic semi-solid agar cultures

Anaerobic semi-solid agar cultures are made with swab samplestaken and transported using the Anaerobic Culturette System. Inmost cases, the same swabs used to make the agar plate culturescan be used to make the semi-solid agar cultures. This is done byinserting the tip of the swab into the semi-solid agar medium andswirling the shaft at least 10 times, slowly as to not entrain air intothe medium.



8-21

After removing the swab from the medium, the tube/vial iscompletely filled with additional medium to displace any air. Thetube/vial is tightly capped and incubated at the appropriatetemperature.

It is suggested that the swab tip be left in the tube/vial when usingthe API medium and reinforced clostridial agar (R.C.A.).

Growth of sulfate-reducing bacteria in the API medium isindicated by the development of a black color diffusing throughoutthe medium. This may take as many as 14-28 days. Growth of theClostridia in the reinforced clostridial medium is first indicated bythe formation of gas bubbles and subsequently the development ofa cloud or turbid appearance within the medium. Sulfide-producing Clostridia will occasionally produce discoloration of theR.C.A. and black sulfide discoloration on API medium.

5. Anaerobic broth cultures

Duplicate swabs and/or the swabs used to make the streak platecultures can be used for the anaerobic broth cultures. The swabsare removed from the transport tubes and immediately insertedinto the broth tube. The shaft of the swab should be swirled at least10 times while the tip is immersed in the broth. Care should betaken not to entrain air into the broth. If the swab is not to be usedfor further culturing, the tip of the swab can be left in the broth bybreaking the shaft just above the tip.

The anaerobic broth culture tubes should be tightly capped duringincubation. Initial indication of growth may be seen usually withintwo to four days. It may appear as the development of gas bubblesclustered on the tip of the swab or at the interface of the liquidlevel in the tube. Growth may subsequently appear as biomass onthe walls of the tube, as a sediment on the bottom of the tube, or asa turbid suspension in the broth. The growth can subsequently besubcultured and/or microscopically examined for furtheridentification and characterization.

Comments

Samples suspected of containing microorganisms will usually consist of a mixedmicroflora. The initial step in the analysis of the sample content is to culture allorganisms present.



8-22

Examination of microbiological deposit samples using culturing techniques should notbe done without accompanying microscopic examination. Many insignificantmicroorganisms exist as part of the microbiological mass collected, and these will growwhen cultured, perhaps in greater numbers or more readily than the significantmicroorganisms. This fact may provide misleading results. Microscopic examination ofthe specimen, as well as culture examination, will help to establish the relationshipbetween specific kinds of microorganisms and deposit formations.

Isolation and Characterization of Microflora from Water Samples

Objective: To describe the method used to culture and isolate microorganisms inmakeup and circulating water. The microflora in circulating water is similar to that inmakeup water. The techniques employed differ only in the quantity of the sampleexamined and in the degree of dilution necessary to make critical interpretations ofresults.

1. Materials

a. Apparatus

1. Sterile sampling bottles

2. Dilution bottles (9.0 or 99.0 ml) with sterile water

3. Petri dishes

4. Pipettes (1.0 and 1.1 ml)

5. Loop inoculating needle


7. Incubator with heat capability up to 37°C for 48 hours


9. Filter tube apparatus if applicable

10. Whirl-paks (sterile plastic bags)

b. Culture media

1. Nutrient agar

2. Mycophil agar



8-23

3. Stokes agar

4. Selective or differential media if applicable

5. Culture collection and transport tubes

2. Procedures

a. Sampling

Sampling points should be carefully selected to obtain representativesamples. Special precautions should be taken to obtain samplescontaining a typical dispersion of material suspended in the makeupwater or circulating water to be examined.

When sampling water that contains dirt, mud, rust, or other debris thatwill interfere with microbiological examination of the specimen, a portionof the specimen should be collected through surface sampling.

Sterile sample bottles or Whirl-Paks should be used to collect andtemporarily store specimens. Samples should be kept at their originaltemperature or chilled if temporarily stored. They should not be exposedto direct sunlight or heated prior to examination.

b. Cultivation

1. Dilution of plating

Fresh water specimens to be examined that are relatively free offoreign matter and are not suspected of being highly contaminatedmay be plated without prior dilution. This is done by transferring0.1 and 1.0 ml aliquots of each specimen directly to petri dishes.However, when specimens appear highly contaminated, dilution isnecessary and is done by transferring 1.0 ml of the original sampleto a dilution bottle containing 9.0 ml of sterile water. The coloniesof microorganisms cultured from the original or diluted specimensshould not appear more dense in the petri dishes than countable.

2. Dilution by streaking

This procedure is suitable for more heavily contaminated samples.By means of a loop inoculating needle, a portion of the specimen isplaced on the surface of a solid medium near the side of the petridish and is streaked or spread over the surface with an inoculating



8-24

loop. The specimen should be spread in parallel streaks, changingdirections on the surface of the medium by rotating the dish four orfive times during spreading.

After each series of streaks, the inoculation needle should beflamed, cooled, and drawn through the streaks already on the plateto produce a diluted population. If a sterile plastic loop is used, itshould be changed after each use. The third, fourth, or fifth seriesshould give the optimum isolation of microorganisms. Thismanipulation accomplishes a thinning out of the bacteria on thesurface of the medium. When streaking is properly performed, thebacterial cells will be sufficiently far apart in some areas of the dishthat the colony developing from one cell will not merge with thatgrowing from another. Each isolated colony is the progeny of asingle cell, hence, a pure culture.

3. Interpretation/characterization

The objective of the examination of specimens using dilutionmethods of cultivation is to characterize the sample through colonyisolation. When this is done, microscopic examinations oradditional culture studies can be made to determine the individualmicroorganisms isolated. The examination of isolates should proveto be an important guide in planning for the best point ofapplication and selecting the product to be employed formicroorganism control, and the examination can often be useful inlocating the origin of microbiological problems.

Comments

Both the plating and the streaking techniques must be done using sterile conditions toavoid misleading results because of contamination from the air, apparatus, and media.

The streaking method is usually more adaptable and more practical for cultureexamination of microorganisms. However, in situations where the microbial populationis low, as in some makeup waters, it may become necessary to use the plate method.

Plate Count Method for the Enumeration of Microorganisms

Objective:

To describe the techniques used for the enumeration of microorganisms by the platecount method.



8-25

Several new products/procedures for enumerating total aerobic populations in bulkwater samples have recently become available. These have proved to be easier, faster,and require less supplies than the procedure described below. The PETRIFILM by 3Mis an example of these products; it has proven to be an effective procedure forenumerating microorganisms in bulk water samples. Procedures for the use of theseproducts are provided by the manufacturers.

The following is used as the traditional procedure for enumerating bacteria populationsin bulk water samples and is generally known as the dilution plate count method.

Plating should be done in a room that is free from air currents and dust. The culturemedia should be selected on the basis of their designed specificity for supportinggrowth of particular types of microorganisms. Nutrient agar for bacteria, Mycophilagar for molds and yeasts, and Stokes agar for iron-oxidizing bacteria are examples thatcan be used.

1. Materials

a. Apparatus

1. Sampling containers (sterile)

2. Dilution bottles (9.0 or 99.0 ml)

3. Petri dishes

4. Pipettes (1.0, 1.1, and 10.0 ml)


6. Incubator with heat capability up to 37°C for 48 hours

7. Quebec colony counter (if available)

8. Filter tube apparatus (if applicable)

b. Culture media

1. Nutrient agar

2. Mycophil agar

3. Stokes agar (Sphaerotilus agar) and broth

4. Cetrimide agar



8-26

2. Procedures

a. Dilution technique

The dilution technique is basically the same for the enumeration of allaerobic and facultative aerobic microorganisms.

1. Place 1 ml of the specimen into a 9.0 ml or 99.0 ml sterile waterdilution bottle. Shake vigorously 40 times. This dilution is 1:10 in a9.0 ml bottle or 1:100 in a 99.0 ml bottle.

2. Transfer with a sterile pipette 1 ml from the first dilution bottle to asecond dilution bottle and shake as before. The dilution is now1:100 or 1:10,000.

3. Continue this dilution sequence using 9.0 and 99.0 ml dilutionbottles until the desired dilutions have been reached. Dilutionsshould be selected so as to provide no less than 30 and no morethan 300 colonies per petri dish. Three 99.0 ml dilutions or 9.0 mldilutions are sufficient for most specimens collected. In the case ofpotable/demineralized water, only one or two dilutions willusually be required.

b. Plating technique

1. The 1.0–1.1 ml pipettes should be used to transfer the dilutedsample to petri dishes. The calculation of the final dilution isobtained by transferring a specific aliquot from the dilution bottlesto the petri dish and multiplying by the dilution factor.

2. Only one pipette per sample is needed to transfer from the dilutionbottles to the plates, provided transfer is in reverse order; that is,transfer from the highest dilution first, followed in sequence to thelowest dilution.

3. Prior to transfer from the dilution bottles to the plates, theappropriate culture medium should be cooled to 45°C and keptready for pouring immediately after the transfer has been made.The temperature of the medium is best maintained in a water bath;this is especially important if many plates are to be poured. Thiswill provide much better colony distribution in the culturemedium. If the agar is too hot, the bacteria may be killed orinhibited, and misleading results may be obtained.



8-27

4. After the transfer from the dilution bottles to the plates has beencompleted, pour the appropriate culture medium into the plates toa slight excess of what is needed just to cover the bottom of thepetri dish. If many plates are to be poured, drying of the specimenand contamination will be reduced if the medium is poured aftertransferring five samples. Agitate the poured plate with a rotating,short, reciprocating motion until uniform distribution of thesample is obtained. Allow the plates to solidify.

c. Incubation of plates

After the plates have solidified, they should be incubated in the invertedposition at the recommended temperature. Normal incubation time is 48hours for most bacteria and from five to seven days for most fungi.Incubation at environmental temperature is acceptable and usuallypreferred although text books frequently recommend 37°C for bacteriaand 28°C for fungi.

d. Enumeration of microorganisms

1. Following incubation, remove the plates and count the number ofcolonies on those plates from the dilution that provides between 30and 300 colonies per plate. Plates that contain less than 30 or morethan 300 colonies are considered less accurate and should bediscarded.

2. Enumeration is based on the number of microorganisms permilliliter of the original sample. Therefore, by counting the platethat has 30 to 300 colonies, the total number of microorganisms permilliliter of sample can be estimated by multiplying the number ofcolonies times the dilution factor.

Comments

Example: You have taken a sample from the fresh water system at plant A for thepurpose of enumerating the bacteria present. You transferred 1.0 ml of this sample tothe first dilution bottle (dilution 1:10 or 1:100). This was further diluted, plated, andincubated at 37°C for 48 hours. Now you are ready for the final step in the enumerationprocess. What is the bacterial population of the fresh water?

The average number of colonies per replicated plate was 165. After checking thedilution factor for this plate, you find it to be 1:10,000, which means that the original 1.0ml of sample taken from the fresh water system has been diluted 10,000 times.Therefore, 165 (colonies on plate) X 10,000 (dilution factor) = 1,650,000 or 1.65 X 106



8-28

bacteria per milliliter. This, 1,650,000 is the estimated number of bacteria in 1.0 ml ofthe fresh water sample.

Detection of Sulfate-Reducing Bacteria

Objective: To describe a procedure for detecting the presence of sulfate-reducingbacteria. Sulfate-reducing bacteria may be classified as obligate anaerobes, whichpropagate only in the absence of dissolved oxygen. The method of detection describedhere involves a biochemical reduction of inorganic sulfates present in the culturemedium to hydrogen sulfide, which causes ferrous sulfide to precipitate, turning themedium black. The culture method for the detection of sulfate-reducing bacteria hasproved to be highly effective. Because of the ease of handling and the convenience ofpreparation, a 10 ml aliquot of API (American Petroleum Institute) agar culturemedium is recommended for detection of the sulfate-reducing bacteria. A discussionpertaining to other testing procedures for the presence of sulfate-reducing bacteria isincluded in the annotated bibliography. A list of commercially available field test kitsused for the detection of SRB is provided later in this appendix.

1. Materials

a. Apparatus

1. Pipettes, 1.0, 5.0, 10.0 ml

2. Spatula

3. Incubator, heat capacity up to 37°C

b. Culture medium

API agar culture bottles

2. Procedures

a. Sampling liquids

1. Sampling procedures for water specimens previously describedshould be used. Care should be taken not to aerate water samplesprior to testing.

2. Using a pipette, transfer approximately 1 ml of the sample to a 10ml API agar culture bottle by inserting the end of the pipette to thebottom of the culture bottle. As the sample is gently released fromthe pipette, slowly withdraw the pipette from the agar so that the



8-29

sample is not exposed to air when the pipette is fully withdrawn.This is an important step in obtaining viable cultures of obligateanaerobic bacteria. If the 10 ml bottle is not completely filled afteradding the sample, fill it with API agar from another inoculatedbottle to displace the remaining air.

3. Cap the agar culture bottle tightly. Do not shake or aerate themedium. If air bubbles are present, uncap and add more sampleuntil the culture bottle overflows. Recap and again check for air.Repeat this process if necessary until no air bubbles are observed.

4. Place the bottle in an incubator at 37°C (± 3°C) and examine itperiodically for color change in the agar. Darkening of the agarindicates the presence of sulfate-reducing bacteria. Occasionally, apositive reaction is received after 24 to 48 hours. When this occurs,microscopic examination is required to confirm the results. Somesamples may require as long as four weeks’ incubation. Therefore,the broth culture bottles should be held for a minimum of 28 daysbefore discarding.

3. Sampling deposits (slime)

a. Caution must be taken in transferring deposit samples from one site toanother. Aeration should be avoided during collection and testing. Areliable sample containing a viable anaerobic microflora can be collectedby probing deep into the inner portion of the deposit. Transfer a smallportion of the specimen to the agar culture bottle immediately, and allowit to settle to the bottom.

b. Cap the agar culture bottle, check for air bubbles, and incubate asdescribed above.

Comments

Efforts should be made to avoid aeration in the preparation of the medium and in thetransfer of the specimen to the API agar culture bottles. A slight amount of dispersed ordissolved oxygen in the medium will reduce the viability of obligate anaerobic bacteria,reducing the sensitivity of the test. Microscopic verification of positive reactions can bemade by preparing a hanging-drop slide of the dissolved portion of the medium.Verification should be made immediately after a positive reaction has been obtained.Desulfovibrio desulfuricans is the most common sulfate-reducing bacteria encountered.Old cultures of this species fail to demonstrate the rapid, spiraling motility that isdemonstrated by an active culture.



8-30

Microscopic Examination of Microbiological and Non-Microbiological Deposits

Objective: To describe the procedure used for microscopic examination of depositscollected in industrial process water systems.

Sample Preparation and Examination: Sample analysis depends on proper proceduresbeing followed and documentation of results and observations (refer to Appendix A,Section II. Microscope).

1. Materials

a. Compound microscope

b. Microscope slides

c. Cover glasses

d. Dissecting needles

e. Petri dish

f. Absorbent paper

2. Procedure

a. Dilute the specimen with water in a petri dish. This immediatelydemonstrates the solubility, dispersibility, and stability of the slime in anaqueous medium. Record observations of general appearance of thespecimen. It is an important step in the examination sequence.

b. Examine the specimen by teasing with the dissecting needles. Thosematerials that are dissolved or easily dispersed in the aqueous mediumusually have less influence on the formation of the deposits. However,those fractions that remain stable as stringy, slimy, gelatinousagglomerates are most likely to be associated with deposit formation.

c. Continue to wash the stable agglomerates until most of the water-solubleand dispersible materials are removed.

d. Transfer a small amount to a clean slide. Prepare the slide using anappropriate mounting technique and stain required.

e. Examine the slide under the microscope. Begin all microscopicexaminations at the lowest magnification. This permits an assessment ofthe staining and can give a rough quantitative estimate of the microflora.



8-31

After the entire mount of the specimen has been observed at lowmagnification (100X), begin interchanging with the high-dry objectivesuntil the desired field of identification has been found. Oil immersion willbe required to observe bacteria. Apply the oil only after the entirespecimen has been examined at lower magnifications and a specific fieldhas been selected for oil immersion observations.

Comments

Gross examination of a deposit can be used to give some preliminary indicationsregarding the causative agent or mechanism of corrosion. However, if a microbiologicalsource is suspected, culturing techniques and microscopic examinations will benecessary to verify the agent.

Membrane Filter Technique for Detection and Characterization of Microflora

Objective: To describe the use of membrane filters for the detection and examination ofmicrobiological contamination in industrial process water systems. The membranefilter provides a tool for the rapid determination of the type and relative degree ofmicrobiological contamination in process water and, in specific cases, makeup water.Unlike culturing techniques, the membrane filter provides immediate results. It candemonstrate the presence of microorganisms such as fungi, bacteria, protozoa, algae,helminths, etc., without the need of employing numerous types of culture media andwithout several hours’ incubation.

Use of membrane filters involves passing a measured volume of water through themembrane using a vacuum filtration funnel device. The microorganisms can then beobserved by microscopic examination of the surface of the membrane filter which hasbeen stained, dried, and cleared.

1. Materials

a. Apparatus

1. Suitable filter holders and membranes are available from GelmanInstruments, Inc., Ann Arbor, Michigan, U.S.A.; Millipore FilterCorporation, Bedford, Massachusetts, U.S.A.; and MembranfilterGesellschaft GmbH, Gottingen, West Germany.

2. Filter holder (Gelman glass filter funnel no. 4370; Millipore Pyrexfilter holder with stainless steel screen No. XX10-047-20; orequivalent).



8-32

3. Membranes (Gelman membrane GA-6, pore size 0.45 micron,diameter 47 mm; Millipore filters, 0.45 micron pore size, diameter47 mm, type HA; or equivalent).

4. Filter flask, 500 ml, with vacuum tube and aspirator pump

5. Microscope

6. Subsurface sampling apparatus


8. Cover glasses

9. Sampling bottles, 1 liter

10. Graduated cylinder, 100 ml

11. Forceps

b. Stains

1. Picric acid - 1.0% picric acid in distilled water,

2. Acid fuchsin - 1.0% acid fuchsin in distilled water, prefiltered

c. Other

Immersion oil, nondrying

2. Procedures

a. Sampling

1. Sampling sites should be selected on the basis of the problemsbeing investigated. Generally, a complete survey of a process watersystem requires sampling from the water source to its end use atthe farthest point in the system. Current, complete flow diagramsof the water system will assist in the selection of points wheresamples can be obtained.

2. When sampling a water system that contains dirt, fiber, rust, orother types of suspended matter, it may be necessary to prefilterthe specimen while collecting it by using the filter tube apparatus.



8-33

This apparatus makes it possible to examine almost any aqueoussystem by the membrane filter technique. If the system is highlycontaminated, smaller volumes or dilutions of the originalspecimen may be necessary. Usually, a volume of 50 to 1,000 ml ofthe undiluted specimen is adequate to make complete membranefilter analysis of water samples.

3. The sampling equipment and filtering apparatus must be keptclean and dry when not in use. When it is necessary to sanitize thesample bottles and filtering equipment, rinsing with commercialhousehold liquid bleach (sodium hypochlorite or Javelle water) isadequate. The equipment must then be rinsed with large amountsof the water sample or with ethyl alcohol to remove thehypochlorite.

b. Filtering and staining

1. If the funnel is not graduated, a graduated cylinder should be usedto provide measured volumes of each specimen filtered. When thisis done, it is possible to make relative comparisons of the degree ofcontamination between samples. This technique is notrecommended for quantitative measurement of microflorapopulations.

2. When the measured amount of water has been passed through themembrane, relieve the vacuum in the filter flask. Gently flood thesurface of the membrane with the picric acid solution to fix andpreserve the microorganisms. Let stand for five minutes or more.After the fixing period, apply a gentle vacuum to remove theexcess picric acid. Wash gently with water. Relieve the vacuum,remove the membrane with forceps from the holder, and place it ina petri dish face up. Flood the membrane with the acid fuchsinstain for two to five minutes, depending on the intensity of stainingrequired to make a microscopic examination. It may be necessaryto repeat the procedure to obtain suitable staining.

3. After staining, the excess stain should be removed by gentlyflooding the membrane with water or by gently dipping themembrane in a beaker of water. Allow the membrane to drycompletely. Membranes can be dried at 100–105°C. It is now readyfor mounting.

4. Section the membrane with scissors. Portions of the stainedmembrane can be stored for several months, thereby providing



8-34

permanent preparations of the specimen. Place a selected section ofthe stained membrane on a microscope slide, and apply a drop ofimmersion oil. The oil will clear the membrane if it is properlydried. The cleared membrane should be completely transparent. Ifnot, further drying is necessary. Place a cover glass over the sectionand examine microscopically.

c. Interpretation

1. The presence of microorganisms, scale, and other debris can beobserved by direct microscopic examination. Too much debris willmake microscopic analysis difficult. The type and amount of non-microbiological material present should be noted. If there is toomuch debris present, repeat the entire procedure using less water.If much iron scale is present, repeat the procedure through thefixing step (addition of picric acid), wash with 50–100 ml of 6NHCL, and proceed with staining as described.

2. Gross differentiation between fungi, filamentous bacteria,protozoa, algae, and helminths can be made by examiningunstained preparations of certain specimens. However, moredetailed examination should be based on stained preparations.Differentiation between microorganisms and non-microbiologicalsolids is facilitated by the staining procedure.

Comment

This technique is not considered applicable as a method for the enumeration ofmicroorganisms. The types of microorganisms (and frequently the kinds of non-microbiological materials) present in the sample are the most useful and reliableinformation to be obtained from the membrane filter technique. This knowledge canoften provide valuable guidance as to the source of microbial contamination and cancontribute to the establishment of the most effective deposit control procedures.



8-35

Procedures for Collecting and Transporting Water Samples

Sampling sites should be carefully selected to obtain representative samples of themakeup water and the system water. Makeup water should be sampled at the pointwhere it is added to the system. If an addition is made from a water storage tank, it isbest to get the sample as the water leaves the tank and goes to the intake riser.Sampling can also be done at the jockey pump. The system piping should be sampled:

• Near the intake riser at the front end of the system

• Midway in the system at a drain point on a cross main line or fire hose hydrant

• At the farthest end of the system, usually at an inspection valve line

A sample approximately 1.0 liter in volume should be adequate for most testing,including microbiological and chemical testing. Duplicate or triplicate samples aresuggested in some cases when testing is infrequent. In stagnant systems, a sample ofthe first flush, as well as a sample flushed for two to three minutes, should be taken.The water should be added to a clean (sterile if possible) container that has been rinseda minimum of three times with the water being sampled. The sample container shouldbe filled completely and the opening sealed tightly if the testing is to be done within12–24 hours after sampling. If sampling is to be postponed, the caps should be looseneduntil it is necessary to tighten them for transportation to the testing lab. Suitable plasticsample containers can be obtained from most biological supply houses.Shipping/packaging kits are also readily available.

Samples can be maintained at ambient temperatures for up to 24 hours. If it is knownthat testing will not be completed within 24 hours, the samples should be refrigerated.Appropriate labeling should include the location, date (time), and identification of theperson doing the sampling. The sampling and any relevant observations (for example,cloudiness, odor, particulate materials, foam) should be logged at the time of sampling.For critical sampling situations, it is suggested that the pH be measured of an aliquot ofthe sample. This can be compared to the pH at the time of testing and may indicate ifchanges in the characteristic of the sample occurred between the time of sampling andtesting. If the sample is taken for microbiological testing off-site, transit time to the labshould not exceed 24 hours.

Procedures for Obtaining and Transporting Pipe Samples

Pipe samples are usually obtained for purposes of system assessment or for failureanalysis procedures. In most cases, the interior surfaces of the pipe are of most interest.Microbiological data, corrosion site morphology (visual appearance of pits ortuberculation), and access to corrosion products for chemical analysis are the primary



8-36

purposes for examination of pipe samples. For these reasons, care must be taken not tocontaminate or compromise the sample when obtaining it or transporting it.

Pipe with an ID greater than 6 inches (15 cm) should be examined for microbiologicaldata on-site. The sampling should be done immediately after removing the pipe beforethe interior surfaces are allowed to dry. Pipe with an ID less than 6 inches (15 cm) canbe transported to an off-site laboratory for examination. Prior to removing the pipe, it isnecessary to clean the exterior surface as thoroughly as possible. This can be done bybrushing and rinsing the dirt and debris from the pipe surface. Removing pipe atthreaded fittings or flanges is desired. However, if this is not possible, removing thepipe test segment can be done with a cutting torch providing that approximately 12inches (30.5 cm) of the pipe length is not significantly affected by the heat of the torch.Band saws or hack saws can be used to cut the pipe. However, cutting fluids orcoolants should not be used because they readily contaminate the sample. If theexamination procedures require that the pipe segment be split lengthwise, this shouldbe done just before the examination is made. A metal cutting band saw without cuttingfluids or coolants may be used to split the pipe. Cutting torches should not be used.

Packaging small ID pipe is done by inserting the pipe, after the exterior surface hasbeen cleaned, into a piece of PVC pipe approximately 1/2 inch (1.3 cm) OD greaterthan the pipe sample. If the pipe segment is going to be examined for microbiologicaldata, the ends of the PVC pipe should be sealed and filled with water from the systemfrom where the pipe sample was taken. This will prevent the sample from drying outduring transit. If no microbiological tests are going to be done, the pipe segment can bewrapped in plastic cling wrap and then covered with aluminum foil. Conventionalpackaging materials can be used for shipping.

Resources for Materials Used to Perform a Microbiological Survey of an FPS

The following is a tabulation of responses to EPRI PSE SWAP Survey No. 98-011,requesting information about the use, source, and cost of microbiological test kits.

Test Kit Supplier Cost

Bio-Scan Betz Dearborn $1600.00(measures ATP) 4636 Somerton Rd,

Trevose, PA215/355-3300

HYCHECK Difco Laboratories, Inc. Refer to price list#9046-36 17197 N. Laurel Pk. Dr

Livonia, MI 48152734/462-8500



8-37

BART Test Kit Hach Co.P.O. Box 608Loveland, TX 80539-0608 Refer to price list

MIC kit FPS BioIndustrial Technologies, Inc. Approximately40105 Industrial Park Circle $100.00 per testGeorgetown, TX 78626512/869-0580

Rapid Check II Strategic Diagnostics, Inc. $ 163.00/10 kits128 Sandy DriveNewark, DE 19713

Easycult Comb Orion Diagnostica Ltd. Refer to price listEasycult - S P.O. Box 83

83 12101 Espco, Finland

BBL Test Kits Becton Dickinson Microbiological Systems Refer to price list7 Loveton CircleSparks, MD 21152410/316-4000

Petrifilm Test Kits 3M Microbiology Refer to price listAttention: 97-HC-603Bldg. 275-5W-05St. Paul, MN 55133-3275800/228-3957

Caproco Caproco International, Inc. Refer to price listHydrogenase Test 217 Virginia Avenue

Conroe, TX 77304

Echa Smartge Echa Microbiology Ltd. Refer to price listEcha Dip Slide Unit M210, Cardiff Workshops

Lewis Rd., Eat MoorsCardiff, CF1 5EJ, U.K.

Several responders indicated that their resource for microbiological sampling andculturing was a service provided by their water treatment chemical supplier Theculturing was done on-site or sent to a remote laboratory. Some plants do local



8-38

sampling and send samples to the corporate environmental or microbiologicallaboratory. Other responders indicated that they do not use field test kits but purchasemicrobiological supplies from specialty biological supply houses such as:

Edge Biologicals, Inc.598 N. Second St.Memphis, TN 38105901/523-0034

Most of the major laboratory supply institutions, such as Fisher Scientific, Pittsburgh,PA, have adequate inventories of materials required to do a microbiological survey.


9-1

9 APPENDIX B: INDUSTRY EXPERIENCES

A number of plants have had experience in dealing with corrosion and fouling of FPSsover the past several years. How these problems were identified and dealt withprovides a database from which other plants can draw knowledge and experience to beused in dealing with their own situations. The FPS Guidelines Task Group recognizesthat much can be learned from the experiences of others even though the circumstancesmay not be identical to any other plant. Therefore, the following discussions of a fewsuch industry experiences are provided as part of these guidelines. The discussions arepresented in the form provided to the Task Group, written and contributed by thosethat have had the experiences, prior to the drafting of this document.

1.1 Fire Protection Raw Water System Corrosion and MIC Problems andEffectiveness of Chemical Treatment Programs

Piping Description

The fire protection piping system includes an extensive network of undergroundpiping forming a loop around the plant (2–14 inch [5.1–35.6 cm] diameter, cement-linedcast iron) and aboveground piping (1–12 inch [2.5–30.5 cm] diameter carbon steel). Thewet portion of the aboveground piping sizes range from 3–8 inch (7.6–20.3 cm)diameter. The corrosion and MIC problems are mainly associated with theaboveground wet portion of the carbon steel piping. Underground cast iron piping hasshown very little corrosion degradation.

Current Maintenance and Surveillance Program

Flow tests at various valve stations, hydrants, and hose stations are performed on ascheduled basis. These tests provide a good measure of water supply capability at thoselocations. By observing the discharge water stream, the presence of clam shells orcorrosion buildup in the system can also be determined. Corrective measures are takenif degraded flow conditions are observed. Corrective measures may involve flushing,cleaning, or pipe replacement. Also, if pipe leaks are identified, the leaks are patched orpipes are replaced. In some cases, significant lengths of pipe sections have been


Appendix B: Industry Experiences

9-2

replaced to preclude recurring leaks in that section Essentially, pipe replacementand/or leak repair is done on an as-needed basis.

Pipe Replacement History

The original pipe installations at Browns Ferry Nuclear Plant (BFN) are over 20 yearsold. During this period, the majority of the pipe replacements have occurred only onceat any location. There are, however, a few exceptions. This shows that pipe degradationhas generally been a slow process occurring over a long period of time. In alllikelihood, piping should have to be replaced only once in the life of the plant. Figure9-1 included in Attachment 1 shows a schematic layout of the plant fire protection loopand depicts main headers that have been replaced or where currently leaks are present.

Chemical Treatment Program

Currently, a chemical treatment program for the raw service water is in place.Chemicals are injected in the raw cooling water (RAW) suction header. The raw servicewater (RSW) pumps take suction from this header and discharge into the high-pressurefire protection (HPFP) headers and raw water overhead tanks located on the reactorbuilding roof. These tanks (10,000 gallons [37,854 liters] each) provide gravity flow intothe fire protection header when the fire pumps are not running. The normal RSW usage(CCW pump bearing lubrication, HVAC systems, cooling tower lift pumps, serviceconnections, minor fires, tests and inspections, etc.) keeps the water flowing to andfrom the overhead RSW tanks and thus distributing the chemicals to various sections ofthe HPFP system. The tank level is maintained automatically by operation of the RSWpumps. Therefore, means of limited chemical treatment is available through the RSWsystem.

Fire Protection Pipe Inspections

The purpose of the pipe inspections was to determine the effectiveness of the chemicaltreatment program and determine existing pipe conditions. Pipe inspection methodsincluded:

• Review of flow discharge tests for any blockages due to clam shells, sediment,deposits, etc.

• Visual inspection of pipe insides during surveillances that involved removal ofstrainer baskets.

• Inspection of pipe insides during repair/replacement. (Repairs were required dueto pipe leaks, valve replacements, etc.)



9-3

• Ultrasonic testing to determine pipe wall thickness at various locations in thesystem (wet pipe headers).

Results of Fire Protection Pipe Inspection

Review of Flow Discharge Tests

Since the implementation of the chemical treatment program, significant improvementhas been noticed during flow discharge tests (that is, flows through transformer delugesystems, hydrants, hose stations, etc.). Flow obstructions were minimal, indicating thatclam production is being effectively controlled. Some hose station locations showedblockage; however, these were attributed to previously deposited clam shells.

Visual Pipe Inspections with Strainer Baskets/Valves Removed

During recent pipe inspections, by removing inline strainers baskets, check valve, etc.,fairly good inside pipe conditions were noted with no deposition of clam shells.However, there was some sediment/nodules buildup, indicating corrosion, MIC, andpitting problems.

Visual Inspections during Pipe Repair/Replacement

Pipe repairs and replacements provided excellent opportunity to examine the pipeinsides. Most inspections revealed significant sediment/nodules buildup, indicatingunder deposit corrosion, MIC, pitting corrosion, fouling, etc. Due to the presence ofextensive pitting corrosion, it was decided to perform ultrasonic testing at selectedsections of large wet pipe headers.

Ultrasonic Testing

A Work Request (WR # C 371710) was submitted to perform ultrasonic testing onselected sections of large wet pipe headers. A 100% scan was performed on 12-inch(30.5-cm) lengths of each identified pipe section, and the lowest readings wererecorded. The results showed significant pipe degradation due to pitting and reducedwall thickness. The readings indicated that wall thickness in several locations was inthe range of 15–60% less than the nominal wall thickness.

Recommendations

Based on the above evaluation, it is concluded that extensive pipe replacement is due todegraded pipe condition (regardless of the chemical treatment program). A suggested



9-4

pipe replacement program is provided in Attachment 1. Some immediate actions can betaken to reduce leaks, corrosion, and MIC problems associated with the HPFP systemand are described as short-term actions. More permanent solutions are described aslong-term actions.

Short-Term Actions

• Maintain the current level of chemical treatment.

• Institute a flushing program to allow chemicals to reach various stagnant lines on afrequent basis.

• Minimize the flow of fresh raw water into the system (introduces oxygen, causinginternal corrosion buildup), for example, fire pump operation should be reduced,fire protection system should not be used as service water, etc.

Long-Term Actions

• Implement a fire protection pipe replacement program. This program willeffectively manage capital expenditure and reduce/prevent unanticipated downtime due to pipe failures. See Attachment 1 for a recommended pipe replacementprogram and estimated costs.

• A feasibility study to convert the existing raw water system to a potable watersystem is included as Attachment 2. Based on the plant life and license extensionplans, this may also be considered as a viable option.



9-5

Attachment 1

High-Pressure Fire Protection (HPFP) Pipe ReplacementEvaluation And Cost Estimate

The purpose of this evaluation is to assess the current condition of the abovegroundHPFP piping serving the main plant areas (that is, turbine, reactor and diesel generatorbuildings). The evaluation is mainly limited to fire protection headers, including somelarge branch connections (stagnant lines) whose failure can render a significant portionof the fire protection suppression systems inoperable. The assessment providessuggested pipe replacement priorities and schedules. Timely pipe replacement willeffectively manage capital expenditure and reduce/prevent unanticipated down timedue to pipe failures.

The evaluation is based on :

• Review of current leaks in the piping system

• Review of Work Orders associated with leak repairs and pipe replacements

• Walkdown and visual observation

• Knowledge of past history of pipe replacements

The report includes a sketch showing the main HPFP headers, locations of present andpast leaks and sections of replaced piping. The tabulation provides pipe lengths,current pipe condition, and suggested replacement schedules. Finally, the pipereplacement cost is provided for each fiscal year for the next five years.



9-6

ServiceBuilding

Unit 1 Turbine Building Unit 2 Turbine Building

3 4

1

Unit 3 Turbine Building

5

2

Unit 1Diesel

Building

Unit 3Diesel

Building

6

7

10

13

24

16

33

12"(30.5 cm)

Supplies to: (typical each unit)H

2 Seal OIl

RFP Oil Tanks 3A, 3B, and 3CTurbine Head EndMain Turbine Oil TanksHose Stations

23

14

25

Unit 1 Reactor Building Unit 2 Reactor Building

21

Unit 3 Reactor Building

22

4"(10.2 cm)

12" (30.5 cm)

4" (10.2 cm)

RFP Oil Tanks (typical)

10" (25.4 cm)

10" (25.4 cm)

86"(15.2 cm) 10" (25.4 cm)

6"(15.2 cm)

Turbine OilTank (typical)

11

4"(10.2 cm)

30

3"(7.6 cm)

8"(20.3 cm)

274"(10.2 cm)

3" (7.6 cm)

4"(10.2 cm)

4"(10.2 cm)

26

HPCI

15

8" (20.3 cm) 1817

28

3"(7.6 cm)

31 4" (10.2 cm)

32

To Hose Stations

8"(20.3 cm)

29

AFFF Header

From RSW Tanks

8" (20.3 cm)

8"(20.3 cm)

3" (7.6 cm)

HPCI2-1/2"

(6.4 cm) 4"(10.2 cm)20

Pipe Not Replaced

Pipe Replaced

Pipe Leaks

Pipe Sections Identification#

Legend

19

To Hose Stations

12

12" (30.5 cm)

Figure 9-1HPFP Main Headers Inside the Plant (Wet System)



9-7

Table 9-1Pipe Replacement Recommendations

NO. DESCRIPTION LENGTH(FT)

PIPEREPLACED

CURRENT PIPECONDITION

SUGGESTEDPIPE

REPLACEMENTFISCAL YEAR

1 12" (30.5 cm) YARDCONNECTION

UNIT 2 TB

25 NO GOOD, NO LEAKS > 2001 -02

2 12" (30.5 cm) YARDCONNECTION

UNIT 3 TB

25 NO MINOR LEAK ATYARD PENETRATION

> 2001–02

3 12" (30.5 cm)EAST/WEST

HEADER U1 TB

175 NO GOOD, NO LEAKS > 2001–02


HEADER U2 TB

170 NO GOOD, NO LEAK(LEAK IN 4" (10.2 cm)H2 SEAL OIL BRANCH

CONNECTION)

> 2001–02


HEADER U3 TB


6 10' (25.4 cm)NORTH/SOUTHHEADER U1 TB


7 10" (25.4 cm)NORTH/SOUTHHEADER U3 TB



HEADER U1 TB

150 NO GOOD, NO LEAKS(LEAKS IN 6" (15.2 cm)

TURB. OIL TK. ANDTURB HEAD END BR.)

2000–01


HEADER U2 TB

170 NO LEAK PRESENT 2000–01


HEADER U3 TB

120 NO GOOD, NO LEAK

(LEAKS IN BRANCHCONNECTIONS)

2000–01

11 8" (20.3 cm)NORTH/SOUTH

HEADER UNIT 1 TB

75 NO GOOD, NO LEAKS 1999–00


HEADER UNIT 2 TB

75 NO LEAKS PRESENT 1999–00



9-8

NO. DESCRIPTION LENGTH(FT)

PIPEREPLACED

CURRENT PIPECONDITION

SUGGESTEDPIPE

REPLACEMENTFISCAL YEAR


HEADER UNIT 3 TB

75 60%REPLACED

GOOD, NO LEAKS 1999–00

REPLACEREMAINING

PIPE


HEADER UNIT 1 RB

240 NO NO LEAKS (SIMILARU2/U3 HEADERSHAVE SHOWNSIGNIFICANT

DEGRADATION)

1998–99


HEADER UNIT 2 RB

240 30%REPLACED


REPLACEREMAINING

PIPE


HEADER UNIT 3 RB

240 80%REPLACED


REPLACEREMAINING

PIPE


HEADER U1 RB

200 <10%REPLACED



HEADER U2 RB

215 YES GOOD NOREPLACEMENT


HEADER U3 RB

200 YES GOOD NOREPLACEMENT

20 4" (10.2 cm) AFFFHEADER

UNIT 1

150 NO GOOD NOREPLACEMENT

21 4" (10.2 cm) AFFFHEADER

UNIT 2

150 50%REPLACED

LEAKS PRESENT 1999–00

REPLACEREMAINING

PIPE

22 4" (10.2 cm) AFFFHEADER UNIT 3

150 50%REPLACED

NO LEAKS 1999–00

REPLACEREMAINING

PIPE



9-9

Table 9-2Fire Protection Pipe Replacement Cost Estimate

DESCRIPTION PIPE REPLACEMENT(FEET)

REPLACEMENT COST * (DOLLARS )

12"(30.5cm)

10"(25.4cm)

8"(20.3cm)

6"(15.2cm)

4"(10.2cm)

3"(7.6cm)

1997–98 1998–99 1999–20 2000–01 >2001

ITEMS 29, 30, 32 & 33 - U 2 REACTOR BLDG

3" (7.6 cm) HOSE CON.HDR.

4" (10.2 cm) HOSECON. HDR.

-U 3 REACTOR BLDG 3" (7.6 cm) HOSE

CON. HDR. 4" (10.2 cm) HOSE

CON. HDR.

30

305

230,000

ITEMS 14, 15,16,17,28,31 -U1 REACTOR BLDG 8" (20.3 cm) N/SHEADER 8"(20.3 cm) E/WHEADER 4" (10.2 cm) (7.6 cm)HOSE CON HDR 3" HOSE CONN HDR - U2 REACTOR BLDG 8" (20.3 cm) N/SHEADER - U3 REACTOR BLDG 8" (20.3 cm) N/SHEADER

640

20

425

940,000

ITEMS 11, 12, 13, 21, 22& 36 -U1 TURBINE BLDG 8" (20.3 cm) N/SHEADER - U2 TURBINE BLDG 8" (20.3 cm) N/SHEADER (2) 6" (15.2 cm) BRANCHCON. (2) 4" (10.2 cm)BRANCH CON. 4" (10.2 cm) AFFFHEADER -U3 TURBINE BLDG 8" (20.3 cm) N/SHEADER 4" (10.2 cm) AFFFHEADER

180

105

200

420,000



9-10

DESCRIPTION PIPE REPLACEMENT(FEET)

REPLACEMENT COST *(DOLLARS)

12" 10" 8" 6" 4" 3" 1997-98 1998-99 1999-20 2000-01 >2001

ITEMS 8, 9, 10, 23,24, 34 & 37

- U1 TURBINEBLDG.

10" (25.4 cm) E/WHEADER

- U2 TURBINEBLDG.


- U3 TURBINEBLDG.


(2) 6" (15.2 cm)BRANCH CON.(4) 4" (10.2 cm)BRANCH CON.- U1/2 DSL GEN

BLDG.3" (7.6 cm)

BRANCH CON.- U3 DSL GEN

BLDG.3" (7.6 cm)

BRANCH CON.-8" (20.3 cm) RSW

CONNECTION

440 150 105 125 80 872,000

ITEMS 1, 2, 3, 4, 5,6, & 7

-U1 TURBINEBLDG.


10" (25.4 cm) N/SHEADER

- U2 TURBINEBLDG.

12" (30.5 cm) YARDCON.


- U3 TURBINEBLDG.

12" (30.5 cm) YARDCON.


10" (25.4 cm) N/SHEADER

335 610 1,070,000

* Estimate is based on FY98 dollars. Use 3% inflation for future years. The above costincludes the following:

(Assuming no design costs)



9-11

• Materials

• Scaffolding up and down

• Insulation removal and application

• Pipe removal

• Pipe fabrication

• Hang pipe

• Weld out pipe

• Hydrostatic tests

• Demobilize

• Fire watch

The unit rate (dollars/foot) for pipe replacement is calculated to be as shown in Table9-3.

Table 9-3Unit Rate for Pipe Replacement

PIPE SIZE 12"(30.5 cm)

10"(25.4 cm)

8"(20.3 cm)

6"(15.2 cm)

4"(10.2 cm)

3"(7.6 cm)

DOLLARS/FT(DOLLARS/M)

1190(3903.2)

1100(3608)

990(3247.2)

870(2853.6)

760(2492.8)

675(2214)



9-12

Attachment 2

High-Pressure Fire Protection (HPFP) Pipe Replacement/Conversion to PotableWater System Evaluation and Cost Benefit Analysis

The HPFP system aboveground wet piping is in a degraded condition. The carbon steelpiping suffers from various forms of corrosion and biofouling including pitting andMIC. To maintain the system in an operable condition, it is expected that the pipe willrequire replacement over the next five years. One method to limit future erosion-corrosion and subsequent pipe replacement is a change to a potable water supplysystem. The following comparison looks at the pros and cons of pipe replacement(Option 1) versus changing the system to a potable water system in addition to pipereplacement (Option 2). A cost comparison is made for the two options. Additionally,the cost of replacing the fire protection piping on an as-needed basis is also provided.Note that the cost of the “do nothing“ option includes items that cannot be quantified.

Table 9-4Options for Pipe Replacement

Description Option 1 Option 2

Longevity Projected life span of piping ~ 20years

Projected life span of piping > 30years

Complexity ofChanges

Simple, like for like pipereplacements, no design changes.

Requires complex design changesincluding:• separation of RSW loads.• Providing alternate water

supplies for RSW users.• New pump house, fire pumps,

tie-ins, etc.

Operation/Maintenance

• Need periodic flushing.• Reduced flow performance over

the years due to E-C, MIC,sediment buildup, etc.

• Requires biocide treatment.• Fire pump maintenance.

• Reduced flushing requirements.• Reduced corrosion effects

resulting in consistent flowperformance.

• No biocide treatment.• Enhanced fire pump operating

logic. Cost • No initial capital expenditure.

• Pipe replacement cost spreadover several years.

• Large initial capital expenditure.• Pipe replacement still required

due to degraded pipe condition.



9-13

Table 9-5Cost Benefit Analysis: 20-Year Remaining Plant Life (1998 Dollars)

Description Option 1 PipeReplacement

Only (Dollars)

Remarks Option 2 PipeReplacement &Potable Water

(Dollars)

Remarks

Potable waterSystem

$0 No initial cost $5,000,000 Initialinstallationcost

Pipe Replacement $230,000 1st YearExpenses

$230,000 1st YearExpenses

Pipe Replacement $940,000 2nd YearExpenses

$940,000 2nd YearExpenses

Pipe Replacement $420,000 3rd yearExpenses

$420,000 3rd YearExpenses

Pipe Replacement $872,000 4th YearExpenses

$872,000 4th YearExpenses

Pipe Replacement $1,070,000 5th YearExpenses

$1,070,000 5th YearExpenses

Flushing $20,000 peryear for 20years

Additionalflushesrequired toclean piping.

$0 No flushing

Biocide Treatment $25,000 peryear for 20years.

Cost ofchemicaltreatment.

$0 No chemicaltreatment

Major Maintenance $150,000

Replace twofire pumps, oneafter 5 yearsand anotherafter 10 years.

Assume pumpfailures requirereplacement.

$0 No pumpfailureassumed.

Potable Water $0 No potablewater use.

$15,000 per year Cost of waterfor makeup,flow andcapability tests.

Present Worth



9-14

Table 9-6Cost Benefit Analysis: 30-Year Remaining Plant Life (1998 Dollars)

Description Option 1 PipeReplacement

Only (Dollars)

Remarks Option 2 PipeReplacement &Potable Water

(Dollars)

Remarks

Potable waterSystem

$0 No initial cost $5,000,000 Initialinstallationcost

Pipe Replacement $230,000 1st YearExpenses

$230,000 1st YearExpenses

Pipe Replacement $940,000 2nd YearExpenses

$940,000 2nd YearExpenses

Pipe Replacement $420,000 3rd YearExpenses

$420,000 3rd YearExpenses

Pipe Replacement $872,000 4th YearExpenses

$872,000 4th YearExpenses

Pipe Replacement $1,070,000 5th YearExpenses

$1,070,000 5th YearExpenses

Flushing $20,000 peryear for 20years

Additionalflushesrequired toclean piping.

$0 No flushing

Biocide Treatment $25,000 peryear for 20years.

Cost ofchemicaltreatment of

$0 No chemicaltreatment

Major Maintenance $150,000

Replace twofire pumps, oneafter 5 yearsand anotherafter 10 years.

Assume pumpfailures requirereplacement.

$0 No pumpfailureassumed.

Pipe Replacement $1,700,000 Assume 50 %of pipingneeds to bereplaced after20 years.

$0 No pipereplacementexpected

Present Worth



9-15

Table 9-7Replace Piping On An As-Needed Basis

Description Estimated Cost Remarks

Pipe Failures and Replacements $2,000,000 in the next 5 years.

$5,000,000 over the following10 years.

Assuming that 1/3rd of the pipewill require replacement anyway, and the installation costswill be 50% more.

Remainder of the pipe willrequire replacement over thefollowing 10 years. The cost willbe 100% more.

Contamination/Radwaste $5,000 per year

Compensatory Measures/ FireWatches

$25,000 per year

Increased Vulnerability No cost basis

Report to Insurance Company/Inspection Findings

No cost basis

Decreased Reliability andCapability

No cost basis

Regulatory Concerns/Violations No cost basis



9-16

Switchyard

Diesel Fire Pump

Remove(may be kept for emergencies)

Electric Fire Pumps

Remove

Turbine Building

Reactor BuildingOverhead Raw

Water Tanks(Remove)

From City Water SupplyNew Water

Tank

New Pump House

Fire Main(Inside Loop)

New FirePumps Connectionto Outside Fire Main

Significant RSW Loads Servedby the HPFP System:• CCW Bearing Lubrication• Cooling Tower Lift Pumps• Off-Gas Glycol Cooling• Charcoal Adsorber Refrig.

Alternate water supply sourceshave to be provided for theabove users.

Figure 9-2Proposed Potable Water HPFP System

2.1 Corrosion Issues as Related to the Philosophy Of Fire ServiceSystem Use

Executive Summary

The amount and extent of corrosion experienced in a fire service system is a directfunction of the way the system is used. Use of the system involves normal use,infrequent use, and subsequent treatment.

TMI uses parts of its fire service system as a domestic water supply. This type of systemuse results in intermittent flow on a daily basis. The cyclic flow provides a fresh supplyof oxygen, nutrients, and bacterial innoculum coupled with the opportunity to exhibitbiological adherence to pipe walls. Consequently, the fire service system at TMI hassome areas of very advanced MIC in progress. In direct contrast, where the fire service



9-17

system has not seen this cyclic usage, the piping is in “like new” condition after greaterthan 25 years of service.

Operating Conditions and Philosophy

The fire system at TMI is fed from the Susquehanna River with a backup from thecirculating water system. The circulating water system is fed from the river but isallowed to concentrate from reuse and evaporation. This water source is last in thepriority of use. An electric-driven, automatically starting fire pump is the first pump tostart and is used manually from the control room on a routine basis when use isexpected to exceed the volume of the 25 gpm (94.6 liters per minute) jockey pump. Ifdemand exceeds the capacity of the electric-driven fire pump, there is an automaticallystarting, diesel-driven fire pump that also draws from the river. Finally, anautomatically starting, diesel-driven fire pump drawing from the circulating waterflume will come on line when demand exceeds both of the river pumps.

The electric-driven fire pump (FS-P-2) is used routinely for providing water for anynumber of plant-related needs. When the need is satisfied, the pump is secured. Thisform of cyclic usage sets up an environment that is conducive to microbiologicalgrowth. Continuous treatment during use would aid in minimizing this effect, but TMItreats its river water intake only at daily intervals. Because FS-P-2 is typically run anytime during the night or day, it is unlikely that the fire service system receives much ofa treatment. This routine use without benefit of chemical layup when complete is theheart of the cyclic use philosophy. Normal system flushes for establishing systemoperability are similar in effect on the fire service system if lay-up chemicals are notapplied when complete. Chemically protected cyclic use is not a threat to the systemlife span, but cyclic use without chemical neutralization of bacterial growth can resultin significant consequences.

Consequences

Figure 9-3 is a photograph of the discharge piping immediately downstream of FS-P-2.The center of the figure is the gate of the pump discharge isolation valve. This valve is a12-inch (30.5-cm) gate valve and gives perspective to the size of the nodules. Thesenodules are approximately 3–5 inches (7.6–12.7 cm) across and about 3 inches (7.6 cm)thick. There have been three through-wall leaks develop in the piping immediatelydownstream of the isolation valve. The downstream piping has leaked prior to thepiping in Figure 9-3 because of the differences in wall thickness. The fitting inFigure 9-3 is a tee and is consequently made of thicker material for the same pipingschedule.



9-18

Figure 9-3Discharge Piping Downstream of Valve FS-P-2

Figures 9-4 and 9-5 are photographs of an elbow and associated piping that wasremoved (and split) from the fire service system on a dead leg that did not possess thecapability to pass water or be flushed. The fitting was removed to accommodate a plantmodification. Note the near pristine condition of the fitting and piping. The line wasinstalled at the time of construction and has been in an aqueous environment sincethen. This leg of the fire service system was never subjected to the cyclic flow that is soinvigorating to microbial growth. The condition of this untreated idle dead legdemonstrates the dependence of microorganisms on a continual supply of oxygen andnutrients.



9-19

Figure 9-4Elbow Removed from Dead Leg

Figure 9-5Piping Removed from Dead Leg

Assessment

Assessing the condition of your fire service system as discussed in Section 4 of thisdocument is based upon inspection, sampling, and operating conditions of the system.Knowing the operating conditions of the system and the bacterial activity of themakeup water will enable an effective estimate of the state of the fire service systembefore samples are taken. The samples and visual inspections will then function to backup the initial estimate of the system condition.



9-20

Conclusion

In conclusion, the operating philosophy of the fire system can dictate the number ofproblems encountered and the cost of treatment expected. If a fire system is used onlyto combat fires and is treated to limit biological growth and corrosion when makeup isnecessary, that system will perform without complication for the life of the plant. Onthe other hand, if the system is subjected to cyclic use, expect through-wall failures andgeneral occlusion with significant flow blockage in small diameter piping. You choosethe operating philosophy of your plant’s fire system and the consequences associatedwith it.

3.1 MIC Tracking Software

Microbiologically induced corrosion (MIC) occurring in a fire service system may beconveniently tracked using advanced computer-aided design (CAD) software. Assamples are performed or as observations are accomplished these results may be placedon the system drawings to demonstrate the progression or extent of MIC in that system.For example, if it is found that MIC is progressing through a system over time, thesetime- and date-stamped entries on the print will demonstrate this trend.

Advanced CAD programs (AutoCAD is used at TMI) will enable the user to create a“layer” on an existing print. The layer does not change the original print but appears asthough it is part of it. If a new revision is issued, the “layer” information can betransferred to the new drawing. A layer provides multiple overlays on a singledrawing that can be individually turned on or off at will. Obtaining the most currentrevision of the system drawing in the CAD format is necessary to begin. The optimumuse of this technique is to have isometric drawings, but P&IDs can also be used. IfP&IDs are used, some information about the lengths and elevations of runs should beadded to the print. As MIC-related information becomes available, it should be loadedinto the correct location on the drawing as a layer. These layers should be specific to atype of information. That is, one layer should be used for sample information, one forsystem observations, one for leaks, one for leaking pathways, one for system elevationsand lengths, etc. A composite drawing of all or some layers can be viewed or printed atany time.

In particular, in a fire service system, a leaking dead end hydrant can bring in fresh,oxygenated, nutrient-carrying water that will accelerate aerobic microbiologicalgrowth. The “source to leak” pathway can be easily redrawn in a layer in red or someother distinguishing color to designate the increased potential for MIC. This pathwould then receive some additional measure of observation or sampling. Thesesamples would be logged onto the highlighted overlay.



9-21

In general, CAD programs offer a very convenient method to visualize the extent or thespread of MIC. Using this tool enables rapid and convenient monitoring of fire servicesystems.

4.1 Palo Verde Nuclear Generating Station Fire Protection SystemCorrosion and Fouling Treatment

4.2 Executive Summary

Palo Verde Nuclear Generating Station (PVNGS) is the largest free-world electricalgenerating station. By being the largest, this requires large systems (sizewise) andcontinuous monitoring of system performance. As an example, PVNGS has a fireprotection system large enough for a small town. This system is required to ensure thesafety of the PVNGS staff, the public, and plant equipment.

The fire water system at PVNGS maintains a reliable source of water to fight andextinguish fires within the three-unit power block areas. The fire water system provideswater flow and pressure to supply the requirements at hose stations and fire hydrants,and when wet pipe and/or preaction sprinkler systems are activated.

Like any other fire protection systems in a small town, problems exist that needattention. There have been several problems with the FP system at PVNGS. Forexample, problems ranging from internal preaction pipe corrosion and failures toexternal main pipe corrosion and failures have occurred. PVNGS has implementedseveral FP system investigations and developed several studies to narrow down theroot cause of the problems experienced.

The major task performed and implemented was to divorce the domestic water systemfrom the fire protection water system. This opened the doors for further treatment andanalysis of the FP system water storage tank. This treatment and analysis consisted ofthe installation of a new water treatment subsystem. This system will inject NaOH intothe FP system tanks to increase the pH to 10.5. In addition, a sulfite solution will beadded as an oxygen scavenging agent, and a non-oxidizing biocide will be added toprotect against MIC. The installation of corrosion coupons provided the necessarymeans to verify the corrosion rates of the FP piping. Enhanced flushing of the systemprovided the means to introduce newly treated water to the power block, as well as ameans of removing the foreign material from the system.

Since the implementation of the new water treatment subsystem and separation of thedomestic water system from the FP system, PVNGS has experienced a reduction in thenumber of pipe and valve failures. The implementation of an effective performance-monitoring program was commissioned to maintain the FP system in a condition ofreadiness. Performance monitoring of the FP system consisting of chemical analysis,



9-22

corrosion coupon analysis, hydraulic analysis, system flushing, visual inspections, andadequate cathodic protection of the FP system piping. Thus far, the performancemonitoring and mitigation techniques have been effective for PVNGS.

This report was prepared to support the EPRI guidelines for the evaluation andtreatment of corrosion and fouling in fire protection systems as a case study. It is asummary of over 10 years of FP system experience at PVNGS. It is not intended thatthis report be a detailed accurate assessment of all the specific problems on the FPsystem experienced at PVNGS over the past 20 years.

4.3 Introduction of PVNGS Fire Protection Water System

The fire water system at PVNGS is a subsystem of the fire protection (FP) system.Portions of the FP system were installed as early as 1975. The installation of the FPsystem was completed prior to commercial operation of Unit 1. The fire water systemprovides a reliable source of water to fire hydrants for hose usage and wet andpreaction sprinkler systems for monitored area protection. Treated well water is storedin two large tanks and dedicated to the fire water system. Full system water pressureand flow can be provided by two of three fire pumps. One fire pump is electric driven,and the other two pumps are each diesel engine driven.

The fire water system maintains a reliable source of water to fight and extinguish fireswithin the power blocks. The fire water system provides water flow and pressure tosupply the requirements at hose stations and fire hydrants for manual fighting. The firewater system provides water flow and pressure as required when wet pipe and/orpreaction sprinkler systems are activated.

The primary source of water for the system is two 500,000-gallon (1,892,706-liter)carbon steel tanks located near the water reclamation plant boundary. Makeup waterfor the storage tanks is supplied by either of two domestic water system site wells.

Fire water is supplied to the distribution system by three 50% capacity horizontal,centrifugal fire pumps. Two of the pumps are driven by diesel engines, and the third isdriven by an electric motor. The pumps take suction from either or both 500,000-gallon(1,892,706-liter) storage tanks and distribute water through two redundant dischargelines. A motor- driven jockey pump can maintain fire header pressure at 125 psig (862kPa) when there is no flow requirement, thus minimizing the necessity for fire pumpstarts.

The fire protection water supply yard main is arranged so that each branch line fromthe yard main to the various areas in each unit’s facilities can be supplied with water byalternate flowpaths. Two-way supplied fire hydrants, controlled by individual curb



9-23

box valves, are installed at approximately 250-foot (76.2-m) intervals along each unit’syard main. Hydrants are equipped with 2-1/2 inch (6.4 cm) hose connections.

The wet pipe sprinkler system at PVNGS is a fixed fire protection system using pipingfilled with pressurized water and activated by fusible sprinklers.

The deluge system at PVNGS employs open directional spray nozzles to provide fireprotection to various areas. This type of system is desirable when water is to bedelivered simultaneously through all sprinklers to wet down an entire area. The watersupply is held back by a deluge valve that is actuated by the operation of a heat-responsive detection system installed throughout the protected area or by a manualhydraulic release.

The preaction sprinkler system at PVNGS is used where an alarm in advance ofsprinkler operation is desired and where it is particularly important to prevent theaccidental discharge of water. The system uses closed sprinklers arranged throughoutthe hazard area. The control unit monitors a normally open thermostat circuit and linetype temperature detector. Upon closure of the circuit, the control unit sends power to asolenoid valve that operates the deluge valve admitting water to the piping.

Water is discharged through the sprinklers after their fusible elements operate.Supervisory “dry” air pressure is constantly maintained in the sprinkler piping toensure the integrity of the piping supply. A trouble alarm sounds if the supervisorypressure is not properly maintained. Loss of air pressure does not cause the delugevalve to open.

The fire water storage tanks provide the fire protection water system with its primarysource of fire water. The tanks are constructed of carbon steel and have a diameter of 47feet (14.3 m) and a height of 40 feet (12.2 m). The tanks are lined with Belzona. Theusable volume of each tank is 500,000 gallons (1,892,706 liters). The tanks are protectedwith magnesium anodes. The two water storage tanks are positioned to prevent onetank’s rupture from affecting the system or washing out the other tank. Piping andvalves are arranged such that loss of either tank or a rupture in the suction line resultsin the loss of only one diesel-driven fire pump.

During normal operation, the site deep well pumps maintain tank levels greater than434,000 gallons (1,642,868 liters) (33.5 feet [10.2 m] tank height). If the level continues todecrease below 388,000 gallons (1,468,739 liters) (30 feet [9.2 m] tank height), a motor-operated fill valve automatically opens to supply water to the storage tanks. Eachpump is rated at 1440 gpm (5451 liters per minute). One pump is capable of completelyfilling one tank in less than 8 hours.

The fire protection water main consists of a closed, 12-inch (30.5 cm), cement-lined,ductile iron, underground pipe loop encompassing all three PVNGS units, the service



9-24

and administration buildings, and site construction buildings. The cement-lined pipehelps to reduce the internal tuberculation deposits.

The yard main is provided with post-indicator valves for sectional control. Post-indicator valves are also located so that the yard loop for any given unit can be isolated.Manually operated water supply gate valves, installed in the sprinkler and delugesystems, are used to isolate operable sections from inoperable sections of the system.

In the event that all plant fire pumps are inoperable or cannot furnish adequate supply,the yard main includes pump connections for obtaining water from the circulatingwater system cooling tower basins by using portable pumping units.

A chemical addition skid is utilized to batch add chemicals into the fire water storagetanks for corrosion control of the fire protection equipment and piping. The chemicalsadded are sodium hydroxide and aqueous sulfite solution for pH adjustment (9.5–10)and for oxygen scavenging.

4.4 Problems Impacting the PVNGS Fire Protection Water System

The original design of the PVNGS fire protection water system storage tanks was tosupply water to the FP system and to supply water to the reverse-osmosis system fordrinking water, domestic water (DW) system. The water distribution was 300,000gallons (1,135,624 liters) for the FP system and 200,000 gallons (757,082 liters) for the DSsystem. The water in these tanks came from a well water supply system. By having thetwo systems use water from these tanks, this caused treatment of the water storagetanks to be difficult. The problem and difficulty facing PVNGS was as follows:

How can the water storage tanks be treated for protecting the FP piping systemagainst corrosion and not cause a health problem or hazards to site personnel for thedrinking water side?

Early in 1989, PVNGS performed an extensive investigation into the concerns regardinginternal corrosion in the FP system due to the corrosive nature of the well water. Table9-8 below shows a typical well water analysis of the FP system water.



9-25

Table 9-8PVNGS Well Water Analysis - Fire Protection System

Constituent Range of Values

pH 8.1 to 8.5P alkalinity: ppm as CaCO3 0 to 12M alkalinity: ppm as CaCO3 127 to 218Chloride: ppm as Cl 144 to 244Calcium hardness: ppm as CaCO3 22.7 to 33.7Total hardness: ppm as CaCO3 40.7 to 66.2Sulfate: ppm as SO4 88.7 to 117Phosphate: ppm as PO4 0.4 to 0.5Silica: ppm as SiO2 34.3 to 42.7Total iron: ppm as Fe <0.1 to 3.1Total dissolved solids: ppm 1001 to 1309Total SUSPENDED solids: ppm 3 to 6Conductivity: µS/cm 1300 to 1700Nitrate: ppm as NO3 13.2 to 16.3Puckorius scaling index: PSI 7.74 to 8.45

The problems identified include:

1. Carbon steel valve scale buildup

2. Underground cement lined carbon steel pipe corroded and pitted (with possibletuberculation) in areas where the lining has failed

3. Fire protection pump casing corrosion

4. Minor corrosion under some blisters in the aboveground plasite lined carbon steelpipe

5. Spalled coating on the water storage tanks, with minor corrosion

In mid-1989, several deposit samples at various locations within the plant fire watersystem were taken and analyzed. One sample was positive for the presence ofGallionella. A 21-day incubation period was applied to several samples. These samplesshowed evidence of sulfate-reducing bacteria (SRB) in several areas. In addition, therewas evidence of bacillus and Diplobacillus bacteria in various areas of the plant. Therewas not extractable organic matter detected at this time. Corrosion rates were shown tobe two to three times the typical corrosion rates of 3–5 mils per year (mpy) [0.08–0.1mm/y] for carbon steel in water environments. Although bacterial contamination waspresent, there were a small number of piping system failures as a result of MIC attack.



9-26

In 1990, deposit sampling continued in an effort to gather more information from otherareas on site that had not been previously tested. The samples continued to showevidence of SRB attack, bacillus, Diplobacillus bacteria, and the presence of Gallionellain several sample locations. Evidence of protozoans and encapsulated bacteria startedto show up in the analysis results. Throughout 1990, monthly samples were taken andanalyzed. The corrosion rates continued at approximately 5–8 mpy (0.1–0.2 mm/y). Amajority of the FP system failures experienced at PVNGS have been limited to specificareas in the preaction systems. The root cause of these failures has been attributed tocorrosion stemming from oxygen cell attack of the wet/dry interface area.

In an effort to slow down the corrosion process on the PVNGS FP piping system, acorrosion inhibitor was added to the system after the FP/DW water storage tanks. Thiswas done in an effort to protect the mild steel and galvanized steel within the system.

Monitoring the corrosion rates of these steels continued and is currently beingperformed today. To protect against MIC attack or slow the MIC attack process, abiocide was added. Flushing of the sprinkler systems was performed to allow thetreated water to reach the pipe requiring protection.

4.5 System Evaluation and Assessment

Fire protection system problems started to be a noticeable problem as early as 1980,when evidence of corrosion on piping systems and valves were present. At that time,repairs of failed piping and valves were made with no real thought as to why there wascorrosion buildup or why they failed. No mitigation techniques were applied orimplemented. The two 500,000-gallon (1,892,706-liter) storage tanks contained waterfrom wells on-site. The water within these tanks was untreated prior to use in the FPsystem.

In 1985, corrosion rates on the order of 9 mpy (0.23 mm/y) were documented on the FPpiping systems. In addition, the presence of MIC started to appear in samples of firewater taken and analyzed as early as 1984. Through-wall pipe failures occurred in thedischarge piping of the fire pumps due to galvanic and general corrosion.

An internal site-wide study was commissioned in July 1989 to evaluate all potentialsolutions for the problems being experienced on Palo Verde’s fire protection systempiping. A multi-disciplinary task team was formed to study the FP system corrosionissue in depth and make recommendations to management. The team members metmonthly to go over action plans and results of the previous month’s activities. Theteams focus was on the following:

How can the water storage tanks be treated or converted for FP system use only,and still provide an alternate source of drinking water?



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The team analyzed all the data collected to date to get a full picture of the extent of thecorrosion and MIC problem in the FP system. Data prior to 1980 was sparsely collectedand not readily available for review and analysis. Based on this, the team decided thatan extensive FP System Corrosion Sampling and Analysis Plan was necessary. Thiswould give the team the information they needed to obtain funds from management toimplement needed system changes.

The plan was broken up into two parts; 1) for the water sampling data collection andanalysis and 2) for the overall FP system analysis, with recommendations. Sitepersonnel took piping samples and analyzed them for corrosion rates and evidence ofcorrosion products. An independent lab was contracted to take water samples andanalyze the results. An independent consultant was hired to review the overall FPsystem problems and provide an expert opinion as to recommendations for upgradesand fixes. Local universities were also used to obtain a third-party review and analysisof the samples taken.

The sampling plan consisted of:

• Water samples

• Water sample cultures to identify MIC-related microbes

• UT to measure pipe wall thickness

• Scrapings of corrosion products

• Visual observations

• Coupon exposure to the water and resulting actual corrosion measurements

• Corrometer exposure to the water and resulting corrosion rate indications

Sections of pipe were also removed and analyzed in locations where the system hasbeen installed for more than 10 years. The water samples were taken from portions ofthe system that were installed in early 1980 from Unit 1 and late 1980 from Unit 3. Theuse of several different techniques, as described above, to measure corrosion activityand damage provided useful correlations of the techniques and validation of thesampling. As data were collected, they were compared to the sampling plan to verifythat the expected results were being achieved. If not, the sampling plan was enhancedto take more samples from other locations. This constant review of the sampling planproved to be useful in the overall assessment of the condition of the FP system withrespect to corrosion.



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The results from the sampling plan indicated similar results as were previously found.Several samples showed positive for the presence of Gallionella. Other samples showedevidence of sulfate-reducing bacteria (SRB) in several areas. There was evidence ofbacillus and Diplobacillus bacteria in various areas of the plant. The UT results did notshow any significant uniform or localized corrosion. The corrosion rate was estimatedto be approximately 8 mpy (0.2 mm/y).

After the data were collected and analyzed, an overall assessment was performed onthe results to develop recommendations for system changes and or enhancements. Theassessment team recommended that the 500,000-gallon (1,892,706-liter) water storagetank currently being used for both the FP system and DW system be separated. Twonew tanks should be purchased solely for the DW system usage. The 500,000-gallon(1,892,706-liter) water storage tank should be used for the FP system only. This wouldallow the water in the 500,000-gallon (1,892,706-liter) water storage tank to be treatedprior to sending the water into the FP system piping.

The team also recommended the installation of a simple treatment system. This systemwould inject NaOH into the FP system tanks to increase the pH to 10.5. In addition, asulfite solution will be added as an oxygen-scavenging agent, and a non-oxidizingbiocide would be added to protect against MIC. When this new system is added to theFP system as a subsystem, new procedures can be developed for system andcomponent flushes.

This recommendation was approved for implementation, and in the winter of 1995, thetwo systems were divorced, and the new water treatment system was added.Additional flushing procedures were implemented along with a water samplingprogram and a corrosion coupon analysis process.

4.6 PVNGS Fire Protection Water System Control and Mitigation

After the FP water storage tanks were separated from the DW system and the newwater treatment was added, PVNGS developed and implemented several flushingprocedures for sprinkler piping, main headers, and water main supply piping andpressure isolating valves (PIVs). In addition, water sampling for quality and corrosioncoupon sampling were implemented to provide an assessment of the FP systemcondition for trending and analysis purposes.

The goal of these new procedures and processes was to protect the FP piping systemfrom further internal corrosion and degradation. In addition, improving the longevityof the FP system was the final outcome or goal of this overall plan. Since the winter of1995, the corrosion rates have fallen and the MIC attack has been reduced. There havebeen very few sprinkler pipe failures and preaction system failures. Flushing of the



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system has removed large amounts of corrosion products and introduced new treatedwater to the system.

Quarterly reports from corrosion coupons have documented mild steel corrosion ratesto be on the order of .3 mils per year or less (0.008 mm/y). The quarterly water analysisreport shows the pH to be less than 10 within the power block. There was littleevidence of SRB and MIC attack from the samples taken. Sampling and analysis isperformed on-site to prevent sample degradation as a result of shipping to an off-sitelab.

Overall, it appears that the FP water system control and mitigation is effective inreducing the mild steel and galvanized steel corrosion. In addition, the water treatmentsystem installed to improve the chemistry of the FP water system appears to beeffective in controlling SRB and MIC attack. Although there has been some presence ofSRB within the powerblock, the overall consensus is that the treatment is working, andthe results are better than previous years.

A sample of the water analysis and corrosion coupon analysis for one unit at PVNGS isshown in Table 9-9.



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Table 9-9Typical PVNGS Water Sample and Corrosion Coupon Analysis

Constituent Range of Values

pH 9.8Conductivity 1700Chloride (Cl) 160 Mg/lNitrite (NO2) <10 Mg/lNitrate (NO3) <4 Mg/lOrthophosphate (PO4) <4 Mg/lSulfate (SO4) 270 Mg/lCalcium (Ca) 1.2 Mg/lMagnesium (Mg) 0.2 Mg/lSodium (Na) 380 Mg/lPotassium (K) <0.5 Mg/lIron (Fe) <0.05 Mg/lCopper (Cu) <0.05 Mg/lManganese (Mn) <0.05 Mg/lAluminum (Al) <0.1 Mg/lZinc (Zn) <0.05 Mg/lNickel (Ni) <0.05 Mg/lChromium (CrO4) <0.05 Mg/lCorrosion rate (mils/yr) <0.1

Within the last three years, there has been an increase in the number of failures of theunderground, concrete-lined, main FP system pipe. The root cause of these failures hasbeen attributed to:

• Improper installation

• The highly acidic soil surrounding the pipe

• Inadequate cathodic protection of the piping system at these locations

Provisions to detect where the piping system may be weak cathodically have beendeveloped and will be implemented in late 1998 and throughout 1999. The goal of theseprovisions is to minimize these failures, determine the weak links within the system,and fix them before a failure occurs.



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4.7 Performance Monitoring and System Enhancements

Since the implementation of the new FP system water treatment subsystem andseparation of the DW system water from the FP system water, PVNGS set a goal tomaintain the FP system in a condition that would extend its life. This goal required theimplementation of a performance-monitoring program. Performance monitoring of theFP system consists of chemical analysis, corrosion coupon analysis, hydraulic analysis,system flushing results, visual inspections, and adequate grounding of the FP systempiping to the plant ground system for cathodic protection.

The chemical and corrosion coupon analysis is performed quarterly, and theparameters monitored are similar to those shown in Table 9-9. The hydraulic analysisconsists of an annual pump performance test and an annual system flow test througheach PVNGS unit. The system flushing is performed annually, and it consists offlushing the underground piping system and valves, as well as the aboveground risersand preaction systems. The visual inspections consist of an annual overall walkdown ofthe system to verify its condition, its readiness to perform its intended function, andoverall system performance inspections performed weekly. Finally, the grounding ofthe FP system to the plant ground grid consists of continuity checks at various locationson the system to verify that the cathodic protection system can perform its function.

From the results received and the monitoring performed since January 1996, the FPwater treatment subsystem appears to be functioning as designed with few failuresresulting from internal corrosion. In addition, flushing appears to be an effective meansof removing foreign material from the system, and the hydraulic analysis/tests haveshown that we have no system blockage within the power block. The weeklywalkdowns of the system status have been effective in identifying potential problemsand system weaknesses.

The results of the ground potential project cannot be assessed at this time; this is a newsystem enhancement. The installation of an air dryer to the service air system, whichsupplies air to the preaction system, has been effective in preventing moist air fromentering the system.

Report approval date: September 1, 1998, contributed by Henry W. Riley, Jr., P.E.


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10 APPENDIX C: GLOSSARY

absorption. The physical assimilation of molecules into solids without a chemicalreaction.

acid. A chemical compound that dissociates in a water solution to furnish hydrogenions.

acid-producing bacteria (APB). Aerobic or anaerobic bacteria that produce acids asmetabolic by-products. Thiobacillus, Clostridium, and Ferrobacillus species are examplesexhibiting this characteristic.

adsorption. The physical adhesion of molecules to surfaces of solids without a chemicalreaction.

aeration. Injecting air through or into water to sweep away other dissolved gases andto equilibrate it with oxygen and carbon dioxide.

aerobic. An environment containing available oxygen. When referring to bacteria,indicates those requiring available oxygen for respiration.

AFSA. American Fire Sprinkler Association.

algae. A simple form of aquatic plant life that uses sunlight for photosynthesis andgrowth. Those that contribute to corrosion and fouling concerns are usually coloredgreen or blue green and form filamentous biofouling masses.

alkalinity (basicity). The quantitative ability of aqueous media to neutralize hydrogenions. The term alkalinity as used in water treatment, usually expressed as equivalentamounts of calcium carbonate, refers to the amount of titratable bicarbonate, carbonate,or hydroxide ions present, as determined by titration to a pH endpoint of 4.2.

alkalinity, total (M). The ability of water to consume acid until it reaches a pH of 4.2,the point where methyl red indicator turns from orange to red. It is the sum of thebicarbonate and the carbonate alkalinities, or the sum of the carbonate and hydroxidealkalinities. It is expressed as ppm or mg/l calcium carbonate.


Appendix C: Glossary

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ammonia. The chemical compound NH3. Ammonia is corrosive to copper and copperalloys. It is consumed by nitrogen bacteria. In FPS treated with nitrite, ammonia can beproduced as a byproduct of denitrifying bacteria.

anaerobic. An environment containing no available oxygen (compare to aerobic). Whenreferring to bacteria, indicates those that can live under oxygen-free conditions.

anion. A negatively charged ion. Examples are chloride (Cl-) and sulfate (SO4

-2) thatmigrates through the electrolyte toward the anode under the influence of a potentialgradient.

anionic. Pertaining to an ion, colloid particle, or metallic surface containing a negativecharge.

anode. 1. In the corrosion process, the area where metal is removed; does not influencethe corrosion rate (compare with cathode). The pH at the anode is generally lower thanthe pH of the water. 2. The electrode of an electrochemical cell at which oxidationoccurs. Electrons flow away from the anode in the external circuit. Corrosion usuallyoccurs and metal ions enter the solution at the anode.

anodic inhibitor. A chemical substance that prevents or reduces the rate of the anodicor oxidation reaction.

antiscalant. A chemical that prevents deposition of scale on system surfaces and insprinklers.

assessment. The procedure of determining the current condition of the system bytesting and evaluating available data pertaining to the capability of the system toperform its design function.

bacteria. Among the simplest single cell forms of microscopic life. When related to FPS,usually classified in terms of oxygen requirements (for example, aerobic, anaerobic) ormetabolic/nutritional characteristics (for example, sulfate reducing, iron oxidizing,slime forming, acid producing, etc.)

base. An alkaline substance that raises the pH of water and yields hydroxyl ions. Abase can neutralize acids.

biocide. A chemical used to kill biological organisms such as algae, bacteria, or fungi.

biodispersant. A chemical that disperses biofilm, biomass, or other organic deposits.

biofilm. A film-like deposit of extracellular polymeric substances produced bymicroorganisms that adheres the surfaces on which microorganisms grow. (See slime)



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biological fouling. A fouling deposit that forms on system surfaces, screens, filters,sprinkler nozzles, and other components that interferes with liquid flow. It is typicallycomposed of biomass and other dirt and debris found in the aqueous medium.

biomass. An accumulation of microorganisms and biofilm that deposits on systemsurfaces and contributes to biofouling.

biostat. A chemical that prevents or reduces the capability of microorganisms toreproduce.

carbon steel. A metal used for piping and equipment, commonly found in coolingwater systems. It is made by combining carbon with iron. It is commonly referred to asmild steel.

cathode. 1. In the corrosion process, the area of metal that is not removed, but thatcontrols the rate of corrosion (compare with anode). The pH at the cathode is generallyhigher than in the water. 2. The electrode of an electrochemical cell at which reductionis the principal reaction. Electrons flow toward the cathode in the external circuit.

cathodic corrosion. Corrosion resulting from a cathodic condition of a structure,usually caused by the reaction of an atmospheric metal with the alkaline products ofelectrolysis.

cathodic inhibitor. A chemical substance that prevents or reduces the rate of thecathodic or reduction reaction.

cation. A positively charged ion that migrates through an electrolyte toward thecathode under the influence of a potential gradient.

cationic. Pertaining to an ion, colloid particle, or metallic surface containing a positivecharge.

caustic. A common term for sodium hydroxide or other strong alkalies.

chlorination. The treatment of water with chlorine or chlorine-releasing compounds.

chlorine demand. The amount of chlorine that must be added to water before aresidual occurs.

chlorine residual. The sum of free and combined chlorine; often termed total residualchlorine (TRO).

clarification. The process of removing suspended solids from water by chargeneutralization, coagulation, and settling.



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combined chlorine. Chlorine complexed with other compounds but still an oxidant,such as chloramines; not as biocidally effective as free chlorine.

concentration cell. An electrochemical cell, the electromotive force of which is causedby a difference in concentration of some component in the electrolyte. (This differenceleads to the formation of discrete cathodic and anodic regions.)

conductivity (of water). The ability of water to conduct electricity. When measuredwith a standard apparatus, it is called specific conductivity and is a function of the totaldissolved solids.

control parameters. Parameters such as pH, conductivity, and corrosion-inhibitorconcentrations that assist in the control of a chemical treatment program. Theseparameters might have an immediate effect on corrosion in the CCW system.

control range. For a given parameter, the acceptable operating region between upperand lower specification limits.

corrosion. The degradation of a metal by a chemical or electrochemical reaction with itsenvironment.

corrosion control by linear polarization (LP) measurements. Corrosion monitoring byan instrument that operates on the principle that a voltage impressed across theinterface boundary will result in a current flow that is directly proportional to thecorrosion occurring on the metal electrode surface. Results are instantaneous (realtime).

corrosion coupons. Metal specimens that are carefully prepared, weighed, and insertedinto the water stream, exposed for a period of time, (usually 30 days or more),removed, and re-weighed to determine a weight loss. The weight loss is used tocalculate a corrosion rate for the specific metal alloy. Results are cumulative over thetime of exposure.

corrosion inhibitor. A chemical substance or combination of substances that, whenpresent in the environment, reduces corrosion.

corrosion monitoring by electrical resistance (ER) measurements. Real-timemonitoring of corrosion by measuring the resistance of a section of wire that is exposedto the water. As the wire corrodes, its cross-sectional area decreases, causing anincrease in resistance. The resistance increase over time is converted to a corrosion rateand, thus, the results are cumulative over the exposure period.

corrosion product solids deposition. Deposits that contain mostly metal oxides, whichare by-products of active corrosion occurring within the system.



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corrosiveness. The tendency of an environment to cause corrosion.

crevice corrosion. The localized corrosion of a metal surface at, or immediately adjacentto, an area that is shielded from full exposure to the environment containing O2 becauseof close proximity of the metal to the surface of another material. The area shieldedfrom the environment becomes anodic.

dealloying. The selective corrosion of one or more components of a solid solution-alloy(also known as parting or selective dissolution).

denitrification. The reduction of nitrate or nitrite to elemental nitrogen and ammonia.

denitrifying bacteria. Facultative anaerobic bacteria that produce nitrogen andammonia from nitrite and nitrate. The Pseudomonas species exhibits this behaviorduring anaerobic respiration.

deposits. Any materials that form accumulations such as scale or sludge. They may bemineral, microbiological, or oils.

dezincification. A corrosion phenomenon resulting in the selective removal of zincfrom copper-zinc alloys. (This phenomenon is one of the more common forms ofdealloying).

diagnostic parameters. Parameters that provide baseline chemistry information thatcan alert the system chemistry reviewer to potential problems or can assist withtroubleshooting of problems.

dip slides. See microbiological monitoring by dip slides.

dispersant. Chemicals added to water systems to keep insoluble solids suspended ordispersed. Dispersants are used to prevent accumulation of deposits or sludge.

dissolved oxygen. The gas O2 dissolved in water. In FPS treatment, dissolved oxygenallows the growth of aerobic bacteria and is detrimental from a corrosion standpoint.

dissolved solids. Matter, exclusive of gases, that is dissolved in water to give a singlephase of homogeneous liquid. (The amount might be determined by calculation[addition of individual constituents] or by evaporating to dryness then weighing theresidue. Note: These methods may not agree; certain adjustments are required to offsetlosses or gains of CO2 in drying, and so on). Also see total dissolved solids.

efficacy. When used in the context of water treatment, it usually refers to the potency oreffectiveness of a chemical treatment compound to produce the desired results.



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electrochemical cell. A system consisting of an anode and a cathode immersed in anelectrolyte to create an electrical circuit. The anode and cathode may be different metalsor dissimilar areas on the same metal surface.

electrode. A conductor used to establish contact with an electrolyte and through whicha current is transferred to or from an electrolyte.

electrolyte. 1. Water containing charged ions. 2. A chemical substance containing ionsthat migrate in an electric field.

facultative anaerobic bacteria. Bacteria that can become either aerobic or anaerobicunder the proper conditions.

film. A thin, not necessarily visible, layer of material.

filter. A device or structure for removing solid or colloidal matter (which usuallycannot be removed by sedimentation) from water. This uses a straining process wherethe solids are held on a medium of some kind (granular, diatomaceous earth, woven,porous) while the liquid passes through.

flocculation. The neutralization of more than one colloidal particle by the same agent.The resulting relatively large neutral particle will settle out of suspension bygravitational attraction.

foulant. Usually any suspended material that deposits on pipe surfaces, in sprinklers,on screens/filters, or in valves that causes a loss in flow capabilities or plugging.

fouling. 1. The deposition of a foulant on system surfaces. 2. An accumulation ofdeposits. This includes accumulation and growth of aquatic organisms on a submergedmetal surface, and the accumulation of deposits (usually inorganic) on FPScomponents.

FPSs. Fire protection systems.

free chlorine. The chlorine content of water in the biologically active form ofhypochlorus acid and/or hypochlorite ion; often termed free available chlorine (FAC).

galvanic corrosion. The corrosion occurring when two dissimilar metals are in contactand one corrodes. An example of galvanic corrosion is when copper and carbon steelare in direct contact, resulting in rapid mild steel corrosion.

galvanic couple. The non-insulated direct contact point of two dissimilar metals atwhich a galvanic corrosion cell is created.



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general (lateral) corrosion. Corrosion that is distributed more or less uniformly overthe surface of a material.

graphitic corrosion. Deterioration of cast iron in which the metallic constituents areselectively leached or converted to corrosion products, leaving the graphite intact.Graphitic corrosion is a form of dealloying.

halogen. In water treatment, pertaining to the oxidizing biocides chlorine or bromine.

hardness. A characteristic of water, generally accepted to represent the totalconcentration of calcium and magnesium ions.

heat-affected-zone (HAZ). That portion of the base metal that is not melted duringbrazing, cutting, or welding, but whose microstructure and properties are altered bythe heat of these processes.

heavy metal. An arbitrary name given to certain metallic ions that can be toxic toaquatic organisms. They might include chromium, lead, mercury, nickel, and zinc.

holiday. A discontinuity in a protective coating that exposes unprotected surface to theenvironment.

impressed current cathodic protection (ICP). Corrosion inhibition produced bysupplying an electric current from a power source external to the electrode system.

inhibitor. A material that reduces a normal tendency to cause scale or corrosion.Usually used to describe chemicals that minimize corrosion through the formation ofprotective films on a base metal.

jockey pump. A pump component of an FPS used to maintain a designed headpressure on the water contained in the system. As pressure drops, the pump deliverswater into the system to maintain the pressure.

localized corrosion. Corrosion that is concentrated in a relatively small area. It ispromoted by a separation between the cathodic and anodic areas. The metal loss formsa penetration rather than general thinning. It is therefore, much more likely to cause anunexpected metal failure than is general corrosion.

macrofouling. Fouling caused by the growth and accumulation of macroorganisms(mollusks) such as mussels, barnacles, snails, and clams.

macroorganisms. A group of organisms that are visually observable; in terms of watertreatment and FPSs, this include mussels, barnacles, snails, clams, hydroids, andbryzoa.



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makeup. That portion of water added to an FPS to compensate for water losses byblowdown (bleed-off), or other losses. Makeup can be raw or pretreated water.

MIC. See microbiologically influenced corrosion.

microbiological monitoring by dip slides. A semiquantitative method of testing fortotal aerobic bacteria. In this process, a slide containing agar is dipped into the bulkwater and incubated for a specified time. Colonies appearing on the slide are comparedto a chart to determine results.

microbiological monitoring by plate count. A technique used to determine the totalnumber of bacteria. Pour plate, spread plate, or membrane filtration are variations onthe basic method.

microbiologically influenced corrosion (MIC). Degradation of material that isaccelerated due to conditions under a biofilm or microfouling tubercle (for example,anaerobic bacteria that can set up an electrochemical galvanic reaction or inactivate apassive protective film, or acid-producing bacteria that might produce corrosivemetabolites).

microfouling. Buildup of a biologically produced slime layer (usually by bacteria) onwetted or submerged surfaces. Microfouling is primarily of concern in FPS because ofpossibly contributing to microbiologically influenced corrosion (MIC).

mitigation. The process of dealing with an undesirable situation by preventing it frombecoming worse, by reducing the severity of the situation, or by eliminating thesituation.

monitoring. The use of techniques, tests, and instrumentation to directly or indirectlyprovide assurance that the water treatment program is providing the desired results.

NACE. National Association of Corrosion Engineers International.

NFPA. National Fire Protection Association.

NFSA. National Fire Sprinkler Association, Inc.

nitrate. The anion NO3. In FPSs, the presence of nitrate is a diagnostic parameter usedto detect the breakdown of a nitrite corrosion inhibitor.

nitrification. The oxidation of ammonia and ammonium salts to nitrate.

nitrifying bacteria. Bacteria that oxidize ammonia and ammonium salts to nitrate.



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nitrite. The anion NO2. Sodium nitrite NaNO2 is a mild steel corrosion inhibitor, usedin FPSs. Nitrite is easily degraded to nitrate by oxygen and Nitrobacter bacteria.

Nitrobacter sp. bacteria. A species of bacterium that oxidizes nitrite to nitrate.

nitrosofication. The oxidation of ammonia to nitrite.

Nitrosomonas sp. bacteria. A bacterial species that oxidizes ammonia to nitrite inneutral or very slightly alkaline medium, using carbon dioxide or carbonates as theirsole source of carbon.

noble metal. 1. A metal that occurs in nature in the free state. 2. A metal or alloy whosecorrosion products are formed with a small negative or positive free energy charge.

nondestructive evaluation (NDE). A monitoring technique that does not damage thespecimen. See ultrasonic testing, eddy current testing, and radiographic testing.

non-ionic. A colloidal particle without a surface charge, or a non-ionized molecule insolution.

non-oxidizing biocide. A biocide whose effectiveness depends upon some propertyother than its ability to oxidize organic material, for example, systemic poison orsurface activity.

oxidizing agent. A chemical that reacts with a target molecule and causes it to lose anelectron (undergo oxidization).

oxidizing biocide. A biocide whose effectiveness depends upon its ability to oxidizeand, thus, destroy organic material, for example, chlorine, bromine, and ozone.

parts per million (ppm). A unit weight of a substance dissolved in one million unitweights of water, for example, one pound per million pounds. Essentially equivalent tomilligrams per liter.

passivation. To make a metal passive.

passive. 1. A metal active in the Emf series or an alloy composed of such metals isconsidered passive when its electrochemical behavior becomes that of an appreciablyless active or noble metal. 2. A metal or alloy is passive if it substantially resistscorrosion in an environment where, thermodynamically, there is a large free energydecrease associated with its passage from the metallic state to appropriate corrosionproducts [8].



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phosphates. Phosphorus-containing chemicals used for corrosion and deposit-controlin cooling systems. Commonly, these occur as orthophosphates, polyphosphates, andorganic phosphates.

pickling. The conditioning of metal surfaces by the production of an oxide film thatadheres to the metal. This is usually done by acid treatment of the metal surface.

pitting. Localized corrosion of a metal surface that is confined to a small area and takesthe form of cavities called pits.

plankton. Microorganisms in FPSs that are found in the bulk water.

polyphosphates. Condensation products of phosphoric acid. Used in water treatmentas corrosion inhibitors and dispersants.

radiographic testing (RT). A nondestructive method that provides images of natural orengineered structures based upon differences in the absorption characteristics of thematerial to incident electromagnetic or particle radiation.

raw water. Untreated water often used as a source of water supply taken from a naturalor impounded body of water, such as a stream, lake, or ground water aquifer.

reducing agent. A chemical that reacts with a target molecule and forces it to gain anelectron (undergo reduction).

sacrificial anode. A third metal specimen that is attached to the less noble metal of agalvanic couple to prevent its corrosion. The sacrificial anode is the least noble metal ofthe three metals; therefore, it corrodes (or is sacrificed) to save the metal beingprotected.

sessile. Microorganisms in an FPS that are not in the bulk water but are attached tosurfaces; part of slime masses.

slime. Gelatinous deposits that are usually microbiological growths (microfouling) thatmight entrap other insoluble materials from the water to cause fouling and possiblycontributing to MIC.

socket weld. A welded connection where one piece fits inside another, as opposed to abutt-weld.

sulfate-reducing bacteria (SRB). Anaerobic bacteria, such as Desulfovibrio desulfuricanssp., that reduce sulfates and produce sulfides.

surfactant. A surface-active chemical such as a detergent.



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suspended solids. The solid, non-soluble material dispersed in water. Total filterablesolids.

total dissolved solids (TDS). The sum of the organic and inorganic materials dissolvedin water.

total suspended solids (TSS). The total amount of filterable materials suspended in thewater.

tuberculation. Formation of knob-like mounds or growths called tubercles that are oftenthe result of corrosion.

turbidity. The reduction of transparency of a liquid due to the scattering of light bysuspended solids.

ultrasonic testing (UT). A nondestructive method for characterizing flaws or wallthickness in metallic piping and components, usually from the outside surface.

under-deposit corrosion. A form of crevice corrosion that is caused by the separationof anodic and cathodic areas by a deposit.

veliger. Shell-less, immature, motile life-form in the growth cycle of mollusks such aszebra mussels and Asian clams.


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11 APPENDIX D: BIBLIOGRAPHY

Reference Books and Manuals

“Biologically Induced Corrosion.” Proceedings of the International Conference onBiologically Induced Corrosion. S. C. Dexter, ed. NACE International, Houston, TX (1985).

Closed Cooling Water Chemistry Guideline. TR-107396. Palo Alto, CA: EPRI, October 1997.

Corrosion Basics: An Introduction, second edition. NACE International, Houston, TX(1984).

Corrosion Inhibitors. C. C. Nathan, ed., NACE International, Houston, TX (1973).

Detection and Control of Microbiologically Influenced Corrosion. NP 6115-D. Palo Alto, CA:EPRI, 1990.

Handbook of Biocides and Preservatives. Chapter 3 by R. W. Lutey, H. W. Rossmoore ed.,Chapman and Hall, New York, NY, 1995.

Inspection, Testing, and Maintenance of Water Based Fire Protection Systems. American FireSprinkler Association, Dallas, TX (1995).

A Practical Manual on Microbiologically Influenced Corrosion. Gregory Kobrin, ed. NACEInternational, Houston, TX, 1993.

Service Water System Chemical Addition Guideline. TR-106229. Palo Alto, CA: EPRI, July1997.

Sourcebook of Microbiologically Influenced Corrosion in Nuclear Plants. NP-5580. Palo Alto,CA: EPRI, 1988.

“Standard for the Inspection, Testing, and Maintenance of Water-Based Fire ProtectionSystems, 1995 Edition.” NFPA 25-95. National Fire Sprinkler Association, Patterson,NY, 1994.


Appendix D: Bibliography

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A Study of Microbiologically Influenced Corrosion in Nuclear Plants and a Practical Guide forCountermeasures. NP-4582. Palo Alto, CA: EPRI, 1990.

A Training Program-Applied Technology on Microbiologically Influenced Corrosion in thePower Industry. TM-1001. Palo Alto, CA: EPRI, August 1994.

Water Text: The Complete Reference of Chemicals, Processes, and Suppliers. Gary Caplan ed.,Caplan Technical Resources, Toronto, Ontario, Canada, 1998.

Information Industry Surveys

Bsharat, Tariq K., Detection, Treatment, and Preservation of Microbiologically InfluencedCorrosion in Water-Based Fire Protection Systems. National Fire Sprinkler Association,Patterson, NY, June 1998.

Fire Protection Piping. E-SWAP Survey 92-507. EPRI-SWAP Technical Library, 0270.2-1607. EPRI NDE Center, Charlotte, NC.

Fire Protection System Water Source. E-SWAP Survey 98-(1/27/98). EPRI-SWAPTechnical Library. EPRI NDE Center, Charlotte, NC.

Microbiological Test Kit. E-Swap Survey 98-011. EPRI-SWAP Technical Library, EPRINDE Center, Charlotte, NC.

MIC - Microbiology

Iverson, W. P., “Mechanisms of Anaerobic Corrosion of Steel by Sulfate ReducingBacteria,” Materials Performance, 21(3):28–30, 1984.

Iverson, W. P., “Microbial Corrosion of Metals.” Advances in Applied Microbiology, 32:1–37, 1987.

Lutey, R. W., “Identification and Characterization of MIC Associated with Metal-Oxidizing Bacteria.” Paper No. 292. Presented at NACE Corrosion/93, Houston, TX,1993.

McMahon, R. F. and R. W. Lutey, “Review of the Effects of Invertebrate Macrofoulingon MIC in Raw Water System.” Paper No. 96-70. Proceedings of the International WaterConference 1996. Engineering Society of Western PA. Pittsburgh, PA, 1996.



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MIC - Detection

Detection and Control of Microbiologically Influenced Corrosion. NP-6115-D. Palo Alto, CA:EPRI, 1990.

Lutey, R. W., “The Detection and Mitigation of MIC in the Power Generating Industry,”Workshop Presentation, Fifteenth Annual Electric Utility Chemistry Workshop, Univ.of Illinois, March 1995. Buckman Laboratories , Memphis, TN, No. W271W, April 1995.

Lutey, R. W., “Identification and Characterization of MIC Associated with Metal-Oxidizing Bacteria.” Paper No. 292. Presented at NACE Corrosion/93, Houston, TX,1993.

Lutey, R. W. and D. P. Mason, ”Identification of Root Cause Failure of Piping in aService Water System. Heat Exchanger Technologies for the Global Environment.” 1994Inter. Joint Power Generation Conference, PWR, 25: 69–78. ASME, New York, NY 1994.

Pope, D. H., “Testing For and Treating MIC.” Sprinkler Age, December 1997.

Pope, D. H., Final Report on the Investigation of a Fire Protection System for Evidence ofMicrobiologically Influenced Corrosion. BioIndustrial Technologies, Inc., Georgetown, TX,1994.

Stoudt, M. R., J. L. Fink, and R. E. Ricker, Analysis of Failed Dry Pipe Fire SuppressionSystem Couplings from the Filene Center at Wolf Trap Farm Park for the Performing Arts.National Inst. Standards and Technology, Rept. No. NISTIR-5389, NIST (MSEL),Gaithersburg, MD, March 1994.

Wendell, J. A., Investigation of the Fire Water Corrosion/Deposit Problem at Diablo CanyonNuclear Power Plant. EPRI- SWAP Technical Library, 0126.5-781. EPRI NDE Center,Charlotte, NC.

MIC - Control and Mitigation

Bshart, Tariq K., Detection, Treatment, and Preservation of Microbiologically InfluencedCorrosion in Water-Based Fire Protection Systems. National Fire Sprinkler Association,Patterson, NY, June 1998.

“Corrosion and Sludge Prevention in Automatic Sprinkler Fire Protection Systems.”U.S. Patent No. 5,803,180, assigned to Roger K. Talley, Sept. 8, 1998.



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Fellers, B. D., Control and Mitigation of Fire Protection System Degradations Due to Foulingand Corrosion. EPRI-SWAP Technical Library, 0126.5-732. EPRI NDE Center, Charlotte,NC.

Hollis, C. G. and R. W. Lutey, “Method for the Control of Deposits Using N,N, -dimethylamides of 18 Carbon Unsaturated Carboxylic Acids.” U.S. Patent 3,558,500,1971.

Lutey, R. W., “The Detection and Mitigation of MIC in the Power Generating Industry.”Workshop Presentation, Fifteenth Annual Electric Utility Chemistry Workshop, Univ.of Illinois, March 1995. Buckman Laboratories , Memphis, TN No. W271W, April 1995.

Lutey, R. W. “Enzyme Technology: A Tool for the Prevention and Mitigation of MIC.”Paper No. 97-71. Proceedings of the 1997 International Water Conference. EngineeringSociety of Western PA, Pittsburgh, PA, 1997.

Lutey, R. W. and P. J. Allison, “Strategies for the Mitigation of MIC in Industrial WaterSystems.” Proceedings of the 1991 International Water Conference, Engineering Society ofWestern PA, Pittsburgh, PA, 1991.

Lutey, R. W. and P. J. Allison., “Strategies for the Mitigation of MIC in Industrial WaterSystems.” Proceedings of the 1991 International Water Conference. Engineering Society ofWestern PA. Pittsburgh, PA, 1991.

Lutey, R. W., V. M. King, and M. Z. Cleghorn, “Mechanisms of Action ofDimethylamides as a Penetrant/Dispersant in Cooling Water Systems.” 1989Proceedings of the International Water Conference. Engineering Society of Western PA,Pittsburgh, PA, 1989.

McReynolds, Gary S., “Prevention of Microbiologically Influenced Corrosion in FireProtection Systems at a Semiconductor Manufacturing Facility.” Paper no. 286.Presented at NACE Corrosion/98, San Diego, CA, March 1998.

Melton, M. A., Nuclear Engineering Study of Fire Protection (FP) System Corrosion andRecommendations for Mitigation. EPRI-SWAP Technical Library, 0076.5-652, EPRI NDECenter, Charlotte, NC.

Moisidis, N. T., “Corrosion Control Program Reduces FPS Failure Risk.” EPRI-SWAPTechnical Library, 0076.5-2043, EPRI NDE Center, Charlotte, NC.

Moisidis, N. T. and M. D. Ratiu, “Corrosion Control Program Reduces FPS FailureRisk.” Power Engineering. 100:4 pp 39–42, April 1996.

Pope, D. H., “Testing for and Treating MIC.” Sprinkler Age, December 1997.



11-5

Rittenhouse, R. C., “Program Reduces Fire Protection System Corrosion.” PowerEngineering, pp 21–23, Oct. 1995.

Shenkiryk, M. “Chemical Cleaning Process for Water Systems.” Water/EngineeringManagement, vol. 3, March 1996.

A Study of Microbiologically Influenced Corrosion in Nuclear Plants and a Practical Guide forCountermeasures. NP-4582. Palo Alto, CA: EPRI, 1990.

A Training Program-Applied Technology on Microbiologically Influenced Corrosion in thePower Industry. TM-1001. Palo Alto, CA: EPRI, August 1994.

Vickers, D. L. and R. L. McGowan. “Water Tanks: Elements of an Effective CoatingSystem.” Materials Performance, vol 9, September 1988.

MIC - Case Histories

“Biologically Induced Corrosion,” Proceedings of the International Conference onBiologically Induced Corrosion. S. C. Dexter, ed. NACE International, Houston, TX, 1985.

“Implementation of Fire Protection Requirements (Generic Letter 86-10).” United StatesNuclear Regulatory Commission, Washington D.C., April 24, 1986.

Lutey, R. W. and D. P. Mason, “Identification of Root Cause Failure of Piping in aService Water System. Heat Exchanger Technologies for the Global Environment.” 1994Inter. Joint Power Generation Conf. PWR 25: pp 69–78. ASME, New York, NY, 1994.

McReynolds, “Prevention of Microbiologically Influenced Corrosion in Fire ProtectionSystems at a Semiconductor Manufacturing Facility.” Paper no. 286. Presented at NACECorrosion/98, San Diego, CA, March 1998.

“A Practical Manual on Microbiologically Influenced Corrosion”, Gregory Kobrin, ed.NACE International, Houston, TX 1993.

Rittenhouse, R. C., “Program Reduces Fire Protection System Corrosion.” PowerEngineering, pp 21–23, Oct. 1995.

Sourcebook of Microbiologically Influenced Corrosion in Nuclear Plants. NP-5580. Palo Alto,CA: EPRI, 1988.

Stoudt, M. R., J. L. Fink, and R. E. Ricker, Analysis of Failed Dry Pipe Fire SuppressionSystem Couplings from the Filene Center at Wolf Trap Farm Park for the Performing Arts.



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Rept. No. NISTIR - 5389. National Institute of Standards and Technology, Gaithersburg,MD, March 1994.

Wendell, J. A., Investigation of the Fire Water Corrosion/Deposit Problem at Diablo CanyonNuclear Power Plant. EPRI- SWAP Technical Library, 0126.5-781. EPRI NDE Center,Charlotte, NC.

Macrofouling

Gauthier, C., Impact of Zebra Mussel Infestation on Fire Protection and Safety Systems ofUtility Generating Stations. EPRI-SWAP Technical Library. EPRI NDE Center, Charlotte,NC.

Gauthier, C., Impact of Zebra Mussel Infestation on the Fire Protection System NantucketThermal Generating Station. EPRI-SWAP Technical Library, EPRI NDE Center, Charlotte,NC.

Lewis, D. P. et al., “A Method for Assessing the Risk of Zebra Mussel Dreissenapolymorpha Infestations in Industrial Fire Protection Systems.” Fire Technology, 33(3),1997.

McMahon, R. F. and R. W. Lutey, “Review of the Effects of Invertebrate Macrofoulingon MIC in Raw Water System.” Paper No. 96-70. Proceedings of the International WaterConference 1996, Engineering Society of Western PA, Pittsburgh, PA, 1996.

Service Water System Chemical Addition Guideline. TR-106229. Palo Alto, CA: EPRI, July1997.

FPS - Design and Materials


“An Investigation of the Water Quality and Condition of Pipe in Existing AutomaticSprinkler Systems for the Analysis of Design Options with Residential SprinklerSystems.” National Bureau of Standards, NBS-GCR-82-399. NBS Center for FireResearch, Gaithersburg, MD, August 1962.

Notarinni, K. A. and M. A. Jackson, “Comparison of Fire Sprinkler Piping Materials:Steel, Copper, Chlorinated Polyvinyl Chloride and Polybutylene in Residential andLight Hazard Installations.” Rpt. No. NISTIR 5339, National Institute of Standards andTechnology, Gaithersburg, MD, June 1994. EPRI-SWAP Technical Library, 0126.5-2039.EPRI NDE Center, Charlotte, NC.



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Shumway, Paul W., “Life Expectancy of Sprinkler System Piping.” Heating, Piping, andAir Conditioning, 67:10, October 1995.

Waller, G., “Stainless Steel for Durability, Fire-Resistance and Safety.” EPRI-SWAPTechnical Library, 0255.0-1543. EPRI NDE Center, Charlotte, NC.

FPS - Inspection, Testing, Maintenance


Inspection, Testing, and Maintenance of Water Based Fire Protection Systems, American FireSprinkler Association, Dallas, TX, 1995.

“Standard for the Inspection, Testing, and Maintenance of Water-Based Fire ProtectionSystems, 1995 Edition.” NFPA 25-95, National Fire Protection Association, Quincy, MA,1994.

Guideline for the Evaluation and Treatment of Corrosion and Fouling in Fire Protection Systems

Documents

Transcript of Guideline for the Evaluation and Treatment of Corrosion and Fouling in Fire Protection Systems