2933 ECDA Brochure V3 - Allied Corrosion · What is ECDA? As defined in the ANSI/NACE Standard...

Corporate HeadquartersAllied Corrosion Industries, Inc.

1550 Cobb Industrial Dr., N.E.Marietta, GA 30066-6611

Telephone: (770) 425-1355Toll Free: (800) 241-0809

Fax: 770-425-1354Email: [email protected]

www.alliedcorrosion.com

Houston Office:

PO Box 41333

Houston, TX 77241-1333

Telephone: (713) 467-6003

Fax: (713) 467-1174

Email: [email protected]

Mobile Office:

1709 Sugar Cane Court

Mobile, AL 36695-2727

Telephone: (800) 241-0809

Fax: (770) 425-1354

POST ASSESSMENT

This step involves analysis of data collectedfrom the previous three ECDA steps todetermine the effectiveness of the ECDAprocesses, establish pipeline integrity, and setfuture reassessment intervals.

Allied Corrosion has the qualifications and thespecific technical expertise required to assistyou with any of the appropriate ECDA fieldservices or manage your entire Pipeline IntegrityManagement program. Corrosion preventionsolutions are our business-----our only business!

All work is performed in accordance with theNACE Standard RP0502-2002, “Pipeline ExternalCorrosion Direct Assessment Methodology”.

A s part of our full-service corrosioncontrol capabilities, Allied Corrosion

Industries, Inc. (ACI) offers the ability tomanage your entire pipeline integrityprogram, or to provide any of the processesassociated with ECDA.

Allied Corrosion has assembled a group offield-proven pipeline assessment specialiststo provide cost effective solutions andcompliance with regulatory requirementsassociated with DOT/OPS Title 49 CFR Part195.452 (Liquid Pipelines) and CFR Part 192(Natural Gas Transmission Pipelines). ACImaintains a qualified and experienced staffof registered professional engineers, NACE-certified Corrosion Specialists, CathodicProtection Specialists, Senior CorrosionTechnologists, and Corrosion Technicians.Our staff has more than two centuriescombined experience in the corrosioncontrol field.

What is ECDA?

As defined in the ANSI/NACE Standard RPO502-2002, ExternalCorrosion Direct Assessment (ECDA) is "a structured processthat is intended to improve safety by assessing and reducing

the impact of external corrosion on pipelineintegrity". The ECDA process consists of fourmajor steps:

• Pre-Assessment• Indirect Inspection• Direct Examination• Post Assessment

PRE-ASSESSMENT

ACI’s professionals are well suited to thetask of collecting historic and current datato determine if ECDA is feasible and toselect the appropriate indirect inspectionmethods for each individual pipelineintegrity program.

INDIRECT INSPECTION

A combination of two or more of the following indirectinspection techniques are used to identify coating faults,anomalies, and/or corrosion activity:

• Close Interval Surveys (CIS): Provides a profile of electricalpotential difference between the pipe and soil (with referenceto a copper/copper sulfate reference electrode). The survey istypically conducted at 10 ft. intervals with impressed currentsources interrupted to provide "on" and "off" profiles to assist inevaluation of compliance with minimum criteria of cathodicprotection.

• Direct Current Voltage Gradient (DCVG): Measures changesin electrical voltage gradients along the pipeline to locatecoating holidays and characterize corrosion activity.

• Alternating Current Voltage Gradient (ACVG): Similar toDCVG surveys except an AC signal is applied to the pipline.

• Soil & Water Analysis: Soil resistivity measurements and waterpH data are collected at regular intervals along the pipeline todetermine corrosivity of the environment.

• Electromagnetic Surveys: A method of locating coatingdefects by measuring changes in the magnetic field that arecaused by the defects. Also referred to as AC CurrentAttenuation Survey.

• Pearson Surveys: An aboveground survey technique used tolocate coating holidays in buried pipelines.

• Global Positioning Surveys (GPS): Typically performed inconjunction with CIS or DCVG. Allied Corrosion utilizes state-of-the-art GPS technology for location mapping and GPSsynchronized current interruption.

• Depth of Cover Surveys(DOC): Usually performedin conjunction with CISand GPS surveys.

DIRECTEXAMINATIONS

After completion of theindirect inspections, theassessment specialists atAllied Corrosion analyzethe data to select sites forexcavations and pipesurface evaluations. Thedirect examination’s datais examined together withprior data to determinethe existence and severityof external corrosion onthe pipeline. Our integrityspecialists can evaluatethe coating performance,provide corrosionmeasurements, pipestrength calculations,corrosion rate estimates,and root cause analysisduring this step.

EXTERNAL CORROSION DIRECT ASSESSMENT (ECDA) and PIPELINE INTEGRITY MANAGEMENT