Erection Manual-pc Piping

Bharat Heavy Electricals Limited 1 of 219

Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

ERECTION MANUAL

FOR

POWER

CYCLE PIPING – TYPICAL

DOCUMENT NO. : TS-P-01&08

Bharat Heavy Electricals Limited

POWER SECTOR TECHNICAL SERVICES

(H.Q.) NOIDA


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

PREFACE

The erection manual for "POWER CYCLE PIPING" Package issued by Power Sector

Technical Services - HQ NOIDA is typical and prepared based on experience of 200 MW / 500

MW BHEL projects. It provides broad guidelines for Erection of Power Cycle Piping.

This can be treated as a standard erection manual for guidelines on the subject. For a

specific project, the relevant drawings, documents, contractual terms are only applicable.

Feed back and suggestions from the users are solicited for further improvements.


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

ERECTION MANUAL FOR POWER

CYCLE PIPING

Copy No.

Revision No. 00

Document No. TS-P,-

01&08 NAME

DESIGNATION/ADDRESS

S/Shri

Prepared by

1., D.Pillai

DGM / Layouts Piping / PEM / New Delhi

2. R. Desikachari

Sr. Manager / Piping Centre / Chennai

3. M.V.Selvam

Manager / PS-QS / Trichy

4. N. Ganesan

Sr. Manager / PS-WR / Nagpur

5. G. Soundararajan

Dy. Manager / PS-Q / Chennai

6. A.K. Khan

Sr. Manager / PS-TS (HQ) / Noida

7. S.Sen

Sr. Manager / PS-NR / Noida

8. N.S.Nair

Sr. Manager / PSTS (HQ) / Noida

9. P.K. Saha

AGM / PS-ER (Q) / Calcutta

10. V. Kandhasamy

DGM / PS-Q / Chennai

Approved by

P.R. Balakrishnan

A.G.M. TS-HQ Noida

Date of Issue

Controlled / Information copy

Issued by

Head/Boilers

Issued to :

Bharat Heavy Electricals Limited

POWER SECTOR

TECHNICAL SERVICES (H.Q.)

NOIDA


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

The following codification system is used for numbering of instructions and the codification of

Log Sheets is as per FQA document.

XX X XX XX XX X

Alpha Numeric Numeric Numeric Numeric Alpha

Type of

Instruction

System Instruction No.

System Designation

Rating of Main Equipment

Type of Manual

Product Code

1.1 Product Code

B - Boiler

BA - Boiler Aux.

T - Turbine

TA - Turbine Aux.

G - Generator

GA - Generator Aux.

P - Power Plant Piping

CI - C &I

1.2 Type of Manual

1 - Erection

2. - Commissioning

3 - Service

4 - Operation

5 - Maintenance

CODIFICATION

FOR

INSTRUCTION NO.


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

1.3 Rating of Main Equipment

01 - 200/210 MW

02 - 120 MW

03 - 110 MW

04 - 60 MW

05 - 30 MW

06 - 100 MW

07 - 235 MW

08 - 500 MW - KWU Design





13 - Industrial Units

14 - 210 MW - Tower Type Concrete Pylon

15 - 210 MW - Tower Type Steel Structure

16 - 500 MW - Tower Type Once through

17 - 250 MW

18 - CCP

1.4 System Designation

01 - Supporting Structure

02 - Pressure Parts

03 - Fine Fittings Valves and Soot Blowers

04 - Ducts, Dampers & Gates

05 - Pulverised Fuel Piping

06 - Fuel Oil Firing System Equipment

07 - Lining and Insulation

CODIFICATION

FOR

INSTRUCTION NO.

CODIFICATION

FOR

INSTRUCTION NO.


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

08 - Recommended Major Erection Equipment

09 - Estimated Product Group Weights per Boiler

10 - Inputs to Erection Engineers

11 - General Safety Guide Lines

1.5 Type of Instruction

G - General

T - Technical

L - Log Sheet

C - Check List

CODIFICATION

FOR

INSTRUCTION NO.


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

INDEX

S.No. Topic Instruction No.

1. Introduction To Piping P^-01 & 08-01/1-17

2. Layout of Power Cycle Piping P^-01 & 08-02/1-12

3. Floating of Piping System P,-01 & 08-03/1-5

4. Bellows & Expansion Joint P,-01 & 08-04/1-5

5. Erection Procedure for Hangers and Supports P,-01 & 08-05/1-32

6. Pre-Erection and Erection Procedure and P^-01 & 08-06/1-47

Checks of PCP

7. Welding, NDE & PWHT P^-01 & 08-07/1-14

8. Regenerative System Chemical Cleaning P^-01 & 08-08/1-8

9. Chemical Dosing and Steam Blowing P.,-01 & 08-09/1-12

10. Do's & Don'ts in PCP P^-01 & 08-10/1-8

11. Quality Checks for Piping Erection P^-01 & 08-11/1-4

12. Erection Welding Procedure for SA 335 P-91 Material P,-01 & 08-12/1-24

13. Precautions for X-20 & P-91 Welding P-01 & 08-13/1-5

Annexures –

- Bar charts on Erection Programme for Power Cycle Piping - 500 MW (TYP)

- Legend - on valves & accessories

CONTENTS


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

INTRODUCTION

The erection of piping is a vital and critical activity in power plant erection. The site

activities related to piping comprise receipt and proper storage of piping components,

proper handling, erection of pipelines and hangers including auxiliary structure etc.To

avoid failure and problems in the piping work, it is necessary to take proper care right

from material receipt stage.

In the following pages, brief guidelines have been given to the site activities. No written

document can substitute years of experience. Hence, this document is conceived as

supplementary to good erection practices.

INTRODUCTION


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

7

RESPONSIBILITY MATRIX (Unless otherwise agreed upon between Agencies)

Utility Boilder SG Piping

Job

<- Ifenginei PC

ering by ->

Others*

TG Piping

LP Piping

Remarks

BOM for procurement

PC

Others

PEM

PEM

PID

PC

Others

PEM

PEM

Pipe Schedule

PC

Others

PEM

PEM

Valve Schedule

PC

Others

PEM

PEM

Data Sheet for SD

PC

Others

PEM

PEM

Instrument Schedule

PC

Others

PEM

PEM

Layout

PC

Others

PEM

PEM

Stress Analysis

PC

Others

PEM

PEM

Dynamic Analysis (if applicable)

PC

Others

PEM

—

Hanger Engineering

PC

Others

PEM

PEM

Detailed Engineering

PC/

BHELTiruchi

PC

PC

As per contract

Procurement

PC/

BHELTiruchi

PC

PC

As per contract

Fabrication, Inspection

PC/

BHELTiruchi

PC

PC

As per contract

IBR Documentation

PC

PC

PC

PC

Note: 1) Above is based on a typical 210 MW.

2) The Matrix Responsibility has to be a ascertained for each contract.

3) Others will be Customer/Consultant/Other BHEL Units.

4) Valves Supply under TG package is directly coordinated by PEM with Valves

division - BHELTiruchi.

INTRODUCTION

TO PIPING


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

PGMA DETAILS

The entire scope of supply of piping as per contract / technical specification are

covered under Product Group (PG) 80 and 81. These Product Groups are sub-divided

into Master Assembly (MA) in a 3-barrel XXX. The Annexure indicates the various

PGMA applicable for the 80 and 81 as PGMA Directory. However, depending upon the

scope of supply by BHEL Piping Centre, the applicable PGMA for a particular Job

number or contract has to be referred.

The PGMA Directory also indicates the requirement of the piping system for the

milestone event. The BHEL valves, sub-delivery items and the hangers and supports

are grouped and issued to suit the milestone event.

The power piping scheme in the Annexure indicates the general terminal points along

with the PGMA details.

INTRODUCTION

TO PIPING


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

INTRODUCTION

TO

PIPING

INTRODUCTION

TO PIPING


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

TERMINAL POINTS IN RESPECT OF ENGINEERING AND SCOPE OF SUPPLY

The scope of supply by Piping Centre as per technical specification in contract specifications

brake down the piping systems defining the boundary viz. the terminal points. The same is

translated in the form of the flow diagram/scheme cleariy indicating the scope of supply by the

agencies. However, the physical terminal points of scope/termination will be indicated in the

contract specification and or as mutually agreed between the Unit / Customer.

The engineering of piping involving layout and stress analysis may not be totally in line with

scope of supply, as the stress analysis shall be done between fixed points.

For example, the main steam piping from SH outlet header upto the stop valve is part of boiler

(PGMA 80-300).The continuation piping from main steam stop valve might be covered under a

separate package of power cycle piping. The analysis of main steam piping from the SH outlet

header upto the turbine nozzle including branches are to be considered in total. In general, the

agency supplying the major portion of piping shall be responsible for the stress analysis.

CODIFICATION

FOR

INSTRUCTION NO.


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

INTRODUCTION

TO PIPING


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

PIPING LAYOUT

In a power station extensive pipework' is required. The layout of piping is always a compromise

between various factors such as cost, operation and maintenance safety, statutory requirements

and aesthetics. The layout designers efforts should be directed at achieving the most optimum

balance of all these factors. The following considerations to

be given while planning the routing of pipelines :

� The pipe routing should be as short and direct as possible to result in minimum pressure

drop and also compact layout.

� At the same time the pipeworks must be so arranged that accommodates thermal

expansion and contraction of the pipes and movement of terminal points. It should be

ensured that the pipe is flexible enough to keep the stresses raised by thermal expansion

within the safe limits of the pipe material and it does not impose undue forces and

moments on the equipment to which the pipe is connected. The pipes should be routed in

areas where some structure is available for supporting the pipes. Sufficient head room

should be provided below the pipes.

� The clearance of pipe with other pipes, equipment or structure should be ensured

considering thermal expansion and thermal insulation.

� Valves should be located in accessible position.

� Pipes should be properly supported; should not impose heavy loads on connected

equipment.

� The routing of pipes and the equipment should be avoided. This will interfere with

handling of the equipment.

� Pipes should be properly sloped to facilitate draining.

Some of the considerations to be given while planning the routing of pipelines are given

below. These are general guidelines and recommendations and not mandatory.

1. Consider the possibility of future expansion of plant. The pipes should be routed in such

a way that the expansion of the plant could be carried out without much modification to

existing pipelines.

2. The pipe routing should be short and direct as possible to result in minimum pressure

drop and also compact layout.

LAYOUT OF

POWER CYCLE

PIPING


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

LAYOUT OF

POWER CYCLE

PIPING


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

LAYOUT OF POWER

CYCLE PIPING


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

3. All pipework must be arranged to accommodate total thermal expansion and contraction

of the pipe material and movements of terminal points.

4. Care must be taken to ensure that no undue strain is put-up on items of plants either by

thermal expansion or improper supports.

5. Run pipes in North-South, East-West, Up & down directions wherever possible. This

will line up pipes with buildings or structural steel lines and make supporting easier. Pipes will

also run along access/walkways and make operation of valves more convenient.

6. Assign in advance separate elevations for North-South and East-West pipe runs. This

helps to prevent interferences.

7. Other considerations being equal, pipe lines should be routed in such a way as to make

maximum use of plant structural members for attachment of hangers/supports.

8. Sufficient head-room should be provided above the pipe to accommodate spring

assembly or any other hanger components. As far as possible a headroom as recommended

below should be made available between the pipe centreline and the bottom of structural steel to

make hanger engineering simple and easy.

For critical lines 2.5 M and more

(MS, HRH, CRH, BFD)

For Extraction lines 2.0 - 2.5 M

(B.F. Suction etc.)

For all other lines 1.5 - 2.0 M

9. Adequate slope should be provided for proper drainage and venting of the lines.

Downward slope to be provided for drainage towards drain points. Upward slope to be

provided for venting pump discharge lines etc. towards vent point. The slopes

recommended for various services are as follows :

1 in 200 for steam/condensate lines.

1 in 100 for Drain lines.

1 in 50 for lube oil lines.

1 in 400 or more for long distance yard piping.]

10. Consideration should be given for clearances required for maintenance and access

required for operation

11. Major lines should be given priority while planning the layout. The logical sequence of

planning the routing of pipelines priority-wise should be as follows :-

LAYOUT OF

POWER CYCLE

PIPING


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

- Critical lines (MS, HRH, CRH & Feed piping)

- Main C.W. Pipe

- Extraction lines, BFP Suction, CEP Suction lines.

- Main condensate line.

- Heater drain lines. Other lines.

12. Pipings which go through concrete floors/walls should be finalised as eariy as possible

in order to furnish the data for civil designers.

13. Most common method adopted for pipe to cross a floor is to provide a sleeve as shown

in figure below. The diameter 'D' of the sleeve should be

0 D = 0 d + thermal movement +100 mm.

Where d = diameter of pipe inclusive of thermal insulation, if provided. D

14. Flange joint should be minimum 300 mm away from support point. Weld joint should be

minimum 100 mm away from support point/building side/any other obstruction.

15. The routing of piping above the pumps should be avoided as this will interfere with

maintenance of the pump.

16. Co-ordinate with equipment supplier/vessel designer to get nozzle orientation to suit most

convenient piping layout :

17. Co-ordinate with electrical designer to ensure that main cables & turnings are shown and

cleared by pipes designs at an early stage.

18. The recommended spacing between the pipes parallel to each other is shown in The

Annexure.

LAYOUT OF

POWER CYCLE

PIPING


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

19. Location of valves plays an important role in operation and maintenance of a plant. Some

of the considerations to be given while deciding the location of valves are listed below.

19.1 Locate all valves for easy accessibility for those which are involved in frequent operation.

Consider frequency of operation while locating manually operated valves. Occassionally

operated valves could be reached by ladders.

19.2 Consider size and weight of valves while locating the same in a pipe line. Provide space

and handling arrangement for heavy valves. For example C.W. B.F. Valves, HP/LP

Bypass valves, 4-way valves etc.

19.3 Non-return valves in extraction lines should be located as close to turbine nozzle as

possible to minimise entrapped steam volume between NRV and Turbine.

19.4 Show the orientation of valve stems on all lines to ensure adequate clearance around valve.

19.5 Situate control valve stations and accompanying valves such that they can be easily

operated from platforms, floors wherever possible.

19.6 Preferably do not "Sandwich" control valves. Place at least one of the isolators in vertical

leg so that pipe spool can be easily taken out to remove. Control valve for maintenance.

Preferred layout of control stations are shown in Annexure.

19.7 Orient valves so that they fall on a common centre line at a similar elevation to

surrounding valves. This will facilitate to provide operating platform, if required,

conveniently.

LAYOUT OF

POWER CYCLE

PIPING


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

19-8 Wherever possible install valves on horizontal line from header and not on vertical take-

off lines so that the lines can be drained when the valves are closed.

19.9 To avoid spooling unnecessary short length of pipe, mount valve directly on to

equipment nozzles/pipe fittings as far as possible. This will reduce unnecessry

weld/flange Joints.

19.10 Always consult the manufacturer's recommendations for installations of special valves.

In general gate valves, plug valves, check valves are to be installed on horizontal lines &

should not be installed up-side with their stem pointed downwards.

19.11. Where valves have to be located in inaccessible position provide platforms or extension

spindle/chain operation. For valves of sizes 40 Nb and below chain operation is not

recommended.

19.12 Even the motor-operated valves require approach for maintenance purposes.

19.13 Best way to locate drain & vent valves and route these pipes is to group them and lead

them to Tundish located at a convenient point as shown below.

20. Some considerations to be given while laying pipes on a pipe-rack are listed below.

20.1 Allocate outer sides of rack for heavy and large diameter pipes and place smaller

diameter and lighter pipes at the centre portion of the rack.

20.2 As far as possible single level rack should be attempted. However when large number of

pipes are to be run on a pipe rack multiple level rack may be considered.

20.3 Provide all loops for expansion over the top of the rack. Never extend loops out

horizontally from pipe rack edges as this will pose supporting problems.

VENT

FLOOR LEVEL

TO DISPOSAL POINT

LAYOUT OF

POWER CYCLE

PIPING


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

20.4 No pipe should be routed on top of the pipe rack supporting columns in case future

upward extension of pipe rack is envisaged.

20.5 All high temperature lines should be supported on shoes and sliding to allow thermal

movement. Medium temperature lines can lie directly on the rack with their thermal

insulation cut-away locally to allow for movement due to expansion.

20.6 Attempt to limit the diameter of piping on a rack to 450 Nb. Larger diameter pipes could

be economically run on sleepers or underground.

20.7 All lines which require expansion loops should be grouped on the same side of the rack.

20.8 When take-off lines are required from a pipe-line on a rack there should always be a

change in direction and elevation.

20.9 Arrangement of piping on a rack should be in a modular basis, i.e. identical layout

between two identical points.

20.10 Arrange instrument lines, conduct lines for cables, cable boxes, etc. on the sides of the

rack (may be outer side).

20.11 Minimum clearance below the pipe rack is dependent on the type of roadways/

pasageway it crosses. Recommended minimum clearances of pipe rack to grade level is

as follows :

For Railways 6.9 Meters

For Major Motor ways 5.3 Meters

For Minor Motor ways 4.5 Meters

For Pipe rack gisle 3.6 Meters

For Stairways 2.1 Meters

For Passage ways 2.0 Meters

20.12 Slopes for the pipelines on rack could be given by two methods, (i) By having sloping

rack itself, this requires fabrication of every supporting column to a different height in

accordance with slope required, (ii) By having a level rack and providing supporting

shoes to pipes having different height in accordance with slope required.

The latter is more convenient and commonly used. This leads to fewer construction

problems.

21. Layout of piping to Air Compressor needs following special considerations.

21.1 To reduce damage to a compressor by abrassion or corrosion the air supply needs to be

free from solids/water etc. Air intakes are best located where the atmosphere is free

from contamination.

LAYOUT OF

POWER CYCLE

PIPING


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

21.2 For efficiency, the air supply should be taken from the coldest zone. If the supply is

taken from outside the buildings locate the suction line above the roof or away from

building as shown in sketch below :

21.3 Keep suction tine as short as possible.

21.4 If the suction line is taken from a header take it from the top of the header to reduce

chances of drawing moisture & sediments.

21.5 A line size isolator is needed if the suction line is taken from a header.

21.6 Consider pickling/painting inside surface of the pipe to prevent rust formation and

reduce the risk of drawing rust into the compressor.

21.7 Discharge piping should be arranged to allow for thermal movements and drainings.

Anchors should be provided to suppress vibrations.

21.8 If air for distribution has not been dried, distribution lines should be sloped towards

points of use and drains. Lines carrying dried air need not be sloped.

If the compressed air is not dried, provide :

a) Traps at all drains from equipment forming or collecting liquid such as inter-

cooler/after cooler/after cooler/separator/receiver etc.

b) Drip legs with traps on distribution headers and Traps or manual drains at the end

of the distribution header.

LAYOUT OF

POWER CYCLE

PIPING


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

Drip legs Manual drain at the end of a

header

22.0 Piping used in D.M. Water service are usually rubber lined. If the pH value of DM water

is maintained at a value between 8.5 to 9.5 normal carbon steel pipes could be used.

Some of the points to be considered while preparing the layout of rubber lined pipings

are as follows :

DRAIN / VENT FROM NEAR BY

PIPE/ EQUIPMENT


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

22.1 Inaccessible corners should be avoided.

22.2 Multiple bends in the piping should be avoided to facilitate visual inspection. There

should be a flanged joint after every bend (90° or 45° or any other angle bend).

22.3 All flanges should be of flat face type. Rubber lining is to be done up to inside diameter

of bolt holes.

22.4 It is recommended -that the layout drawing is reviewed by the agency responsible for

rubber lining before finalising the routing.

22.5 Hydraulic test/vacuum test of the vessel/piping should be done prior to rubber lining.

22.6 For smaller diameter i.e. 80 Nb and below rubber lining is not recommended as it is

difficult to rubber line such small bore.

23.6 As the pipe moves due to thermal expansion the support point on the pipeline also gets

displaced. The change in this location causes an inclination to vertical line by 0°. This

/

23.7 Struts/snubbers should be erected in cold position in such a way that they become

straight in hot condition due to pipe movement.

23.8 Design of aux. structure for supports/hangers are to be done with higher safety factor. A

stress value of 1000 kg/cm2 is to he used for sizing the beams.

should be limited to 4°

Where the movement is

large and sufficient head

room 'h' is not available,

the initial support point

could be shifted towards

the direction of

movements as shown in

the sketches; so that the

angularity from vertical

line is kept with in the

permissible limit.

LAYOUT OF

POWER CYCLE

PIPING

LAYOUT OF

POWER CYCLE

PIPING


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

Pipes and also the difficulty in inspection. For such small bore pipes stainless steel

piping is preferred.

23.0 Considerations to be given while deciding the location of pipe supports.

23.1 The piping system should be self supporting as far as practicable i.e. the load of piping

system should not be transferred to the equipment to which they are connected.

23.2 Excess flexibility shall make additional supports/restraints necessary to avoid vibrations

in the pipe lines.

23.3 As far as possible the supports/hangers are located in such a way as to make it possible

to attach directly with the station structural members. Wherer it is not possible, a tie

beam may be provided. Cantilever/brackets for attaching the supports should be limited.

A max. value of 200 Kg. m turning moment is permissible to be transferred to structural

members by cantilever.

23.4 Distance between supports on horizontal run of pipes depends on pipe size, type of flow

media, working temp. etc. Recommended spans for commonly used pipe sizes at various

temp. are indicated in table at Annexure.

23.5 When a pipe takes a turn in horizontal plane, a support should always be placed

following the bend in one of the sides.

The total length ( x- y) should be less than the recommended span.

LAYOUT OF

POWER CYCLE

PIPING


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

LAYOUT OF

POWER CYCLE

PIPING


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

FLOATING OF PIPING

SYSTEM

FLOATING OF

PIPING SYSTEMS


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

In case of KWU turbines almost no weight of the piping is to be transferred to the turbine/valve

nozzles (ESV & CV, IV & CV). This is specially required for Main Steam, Cold Reheat and

Hot Reheat piping.

To achieve this requirement the designer carries out a weight distribution analysis of the

piping considering that the exact weight of the piping is supported in the cold conditions and

freeing the nozzles where no dead weight is to be transferred. The designer locates the supports

in such a way that theoretically the pipe deflections at the unconnected nozzles points are very

low. The actual pipe weight would vary w.r.t. the theoretical design weights due to pipe

tolerances, variation in actual insulation weights and component weights. To take care of this

load variation as well as to ensure that no dead weight is transferred to the turbine/valve

nozzles, the piping is floated on unlocked spring supports before connecting them to

turbine/valve nozzles. Variation of toad is taken care of by suitably increasing or decreasing the

loads taken by the springs by using turn buckle for variable load hangers and turn buckle as well

as the load adjustment sensors for constant load hangers. When the piping is aligned into

position by adjusting the hangers, they are welded to the nozzles. The designer keeps a margin

on the springs, during selection, to take care of this variation.

The floating of the piping is to be done after the piping has been insulated. The final

hanger settings in the cold condition have to be noted down and corresponding markings made

on the hanger scale. A proper protocol of the hanger settings are to be maintained & hanger

setting should not be disturbed. The valve bodies must to be in their design weight after

completion of the piping installation.

In the event that it becomes absolutely essential to float the piping before the application

of insulation, then their components must be considered through corresponding supplimentary

weights at the respective hanger locations. The supplimentary weights at each hanger location

has to be accurately calculated and assistance from the piping designer is necessary It may be

appreciated that even if the piping is floated this way, the error due to the difference in actual &

theoretical insulation weights can not be eliminated.

FLOATING OF

PIPING SYSTEMS

FLOATING OF

PIPING SYSTEMS


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

Piping Relaxation

Piping subjected to high temperature and stress relaxes with time due to yielding and

creep. The rate of relaxation would vary in different parts of the piping as they are stressed

differentially. For calculation purpose it is assumed that piping subjected above 400° C relaxes

eventually to 100%. For temp between 300°C a 50% relaxation is considered. As the piping

relaxes in the hot condition the piping will start getting more & more stressed in the cold

condition. Finally if you assure 100% relaxation taking place, complete reversal of stresses and

forces & moments will take place in the pipe in the cold condition. Forces and moments coming

on the turbine are based on the immediate hot condition and the cold condition after pipe

relaxation.

One of the other implication of pipe relaxation is on the pipe movements on hanger

deflections. As the exact pipe weight is supported in the cold condition, the spring force will not

be equal to the pipe weight in the hot condition. Thus due to pipe relaxation the pipe would tend

to move towards the cold positions. Here 100% relaxation is assumed the pipe in the hot

condition will tend to settle to the initial cold position. Thus the hangers will also have a range

of movement and one cannot expect the same cold to hot movement through out the life of the

piping system. Hence it is not advisable to reset the hangers once the system is floated. As the

pipe relaxes in the hot condition the initial hot positions will not match with the hot positions at

a later date. Different parts of the piping will relax differently.

During overhauling / inspection of the steam turbine, steam supply pipes are sometimes

required to be disconnected from the turbine nozzles. Due to relaxation of the piping in the hot

condition and as the piping is now skewed in the cold condition, once the piping is disconnected

these pipes have to drift away from the corresponding turbine nozzles. The

overhauling/inspection persons needs to know the extent of drift expected, and if necessary can

take the help of the piping designer.

Cold-pull ups

The practice of giving cold pull ups in piping system to limit forces & moments on

equipment nozzles, though recommended by piping codes are usually avoided due to the

difficulty of its actual application. For piping which are to be floated, giving a cold-pull ups

made even more impracticable to apply.

In rare cases where cold pull ups are resorted' to, the following procedure may be

adopted.

FLOATING OF

PIPING SYSTEMS

FLOATING OF

PIPING SYSTEMS


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

The piping is connected sequentially from one anchor to all the other anchors where

there are Cold pulls, fabricated spool pieces / templates are temporarly installed which enforces

the desired gaps and or centations. The complete piping system upto all anchors should be then

connected. AH restraints and spring hangers should be in position. The spring hangers should be

in the unlocked position during cold pulling. The templates are removed prior to the actual cold

pull. In closing the cold pull gaps there should be only parallel traslation of the matching ends

and no relative rotations. To achieve this cold spring locations can be selected at the points of

minimum torque

2.0 PREPARATIONS

2.1 Hydro test of the entire system under flushing should be completed. After all the

regenerative equipments are installed in position complete the temporary pipe line

connections as shown in the enclosed schemes.


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

ERECTION OF PIPING CONNECTED TO PUMPS - BOILER FEED SUCTION

AND BOILER FEED DISCHARGE PIPING.

BFD piping, loop piping between Booster Pump & Feed Pump and BFP Discharge

piping should not be floated during erection as the allowable forces & moments on the pump

nozzles cater for both thermal and dead weight components. The piping designer while

designing the piping keeps the forces & moments due to thermal & dead weight within the

nozzle allowables.

Each piping has to be erected in total upto all the anchors. Thus if there are three

pumps the piping to all the three pumps wilt have to be erected simultaneously before the

piping is floated.

The following sequence of erection of pump and piping should be followed :-

1. Carry out complete erection of the drive train, that is Booster Pump, Feed pump &

Motor adhering to the alignment requirements prescribed for each stage as per procedure

laid down by pump manufactuer and tighten all holding down bolts as prescribed.

2. The piping should be erected independent of the pumps, which should not be disturbed

once erected.

3. The piping should be first laid in position by locked permanent spring supports and

temporary supports where ever necessary. After the final matching piece is welded all

the temporary supports should be removed and the piping should be insulated. The

spring supports should be checked for the required settings. The spring should be

unlocked only after the pipe line is filled with water.

FLOATING OF

PIPING SYSTEMS


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

BELLOWS & EXPANSION

JOINT


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

BELLOWS EXPANSION JOINT

Bellows Expansion Joints are generally recognized as the simplest and most versatile

solution to the problem of dimensional changes in a pipeline due to thermal expansion or

contraction. But expansion bellows are also the most highly stressed parts of a piping system.

Thus the bellows design combined with safety at operation is of utmost importance. Bellows

design are usually based on EJMA (Expansion Joint Manufacturers Association) code.

The function of an expansion bellow is to permit movement while containing tne

pressure within the System. In operation it subjects the system to various forces which must be

allowed for if the bellows is to perform correctly and safely.

A major force to be considered when matching a choice of bellows is the end pressure

thrust. Unrestrained expansion joints in any pressurised closed system will tend to expand

outwards. This is only resisted by the inherent spring stiffness of the bellows and rigidity of the

system. Thus an unrestrained bellows will impose on the system with which it is fitted on end

thrust equal to the product of the effective cross sectional area of the bellows and the pressure

acting on that area.

Depending on restraining arrangement, bellows may be termed as Untied, Tied (with 2

tie rods) Tied (with min 3 tie rods), Hinged & Grinball. Bellows may be further demarked as

single bellows or double bellows.

Untied Single Bellows

Tied double bellows

(with 2 tie rods)

BELLOWS

EXPANSION JOINT

BELLOWS

EXPANSION JOINT


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

Tied Double bellows

(with 3 tie rods)

Hinged bellows

(Single)

Ginball bellows

In case of United bellows the pressure thrust is imposed on the piping system. In all other cases

the pressure thrust is contained by the tying arrangement

Bellows absorb thermal expansion by elongating /

compressing axially

Angular rotation is absorbed

by the bellows elongation on

one side and compressing on

the other side.


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

Bellows absorb thermal expansion only by there two means?

Hinged Bellows

Tied bellows

(with 2 tie rods)

absorb lateral

movement by the

bellows taking angular

rotation in one plain

Tied bellows

(2 tie rods)

Takes rotation in the

other plain.

Installation

— Care should be taken to avoid any damage to the bellows such as dents, scores, are

strikes and weld spatters.

— The expansion joints should not be stretched or compressed in order to absorb defects

along the length of the pipe or to rectify any misalignments.

— Once the expansion Joint has finally been installed and secured, all the shipping devices,

if any. must then be removed and not before.

— Expansion joints must be fitted according to the direction of flow in relation to the

internal sleeve.

— Expansion joints must be fitted in the correct orientation of the tieing arrangement. i.e.

the tie rods for tied bellows and hinges for hinged bellows.


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

Post installation inspection

— Check that the expansion joint has tie fitted in the correct place.

— Check that the expansion joint has been correctly installed with regards to the direction

of flow.

— Check that all shipping devices have been removed.

— Check that all supporting structures, restraints and anchors have been correctly installed

as planned.

— Check that there are no misalignments in the expansion joint and they are installed in the

correct orientation as envisaged.

— Check whether the gaps between limit rod nuts and flanges for untied bellows are as per

design to take care of expansion and contraction.

Inspection during and immediately after system pressurisation

— Check that there are no leaks.

— Check that the bellows are stable.

— Check that all the restraints, guides, anchors, expansion joints and other components of the

system are secure and resistant.

Periodic in-service inspection — Check to see if the movements are being absorbed by the expansion joints in the manner

for which they were designed.

— Check for unexpected vibrations.

— Check for existance of any signs of external corrosion, stack mechanical components

(screws, tie rods, etc) and also check that the restraints, guides & anchors etc. are in perfect

working order.

Note : For untied bellows with limit rods correct gaps between nuts flange to be

provided to take care of expansion & contraction.

— Check that dust and other particles have not built up between the an volutions restricting its

movements.

BELLOWS

EXPANSION JOINT


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

BELLOWS

EXPANSION JOINT


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

ERECTION PROCEDURE

FOR HGANGERS AND

SUPPORTS


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

Hangers and supports play a very vital role in the piping engineering. Piping applicable to

high pressure super heated steam (high energy piping) and water has to be properly supported

to avoid any failures in the system. Hangers and supports or in general the piping supporting

system is essential to take care of the following needs :

Q To balance the gravity force i.e. dead weight due to pipe weight and insulation weight.

Q To share the thermal expansion force such that the total stress at any section of the

piping is within the limits.

Q To limit the end forces and moments.

0 To absorb the dynamic loads.

Q To avoid sagging so that all the condensate can get drained.

Q To guide the piping movement to avoid uncertainties in supporting efforts.

DRAWINGS AND DOCUMENTS

The erection engineer before he plans for erection activities of hangers and supports should

ensure that the following drawings and documents are available at site. If some of the

documents/drawings are not available, he should take necessary action to obtain from the

agencies concerned.

Q Piping isometric drawings - this drawing indicates the location of hangers.

0 Hanger schedule cum D.U. allocation table - this gives hanger tag number, hanger assembly

drawing No., total load taken, spring type (i.e. CLH or VSH), pipe elevation, spring

compression position (cold/hot values) for each hanger. It also gives D.U. Nos and quantity of

hanger components corresponding to the item Nos. indicated in the hanger assembly drawings.

This enables the erection engineer to identify the components corresponding to hanger assembly

requirements.

Q Hanger data sheets furnished by customer's engineering consultants (this includes auxiliary

structure arrangement). - Hanger data sheet provides information regarding hanger No., thermal

movement of pipes, load, hanger location plan, hanger assembly arrangement etc.


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

Q Hanger assembly drawings in the form of standard drawings or individual drawings as

applicable - these drawings indicate the type of assembly, item and No. and the quantity of

hanger components.

0 Consultant's drawings for secondary structures for hangers (to be obtained from customer).

Secondary structure details are also available in the hanger data sheets.

Q Shipping list - indicates D.U. No., and cumulative quantity of hanger components

required for different hangers.

Q In the case of 500 MW units, the hanger schedules and hanger assembly drawings are

combined together in the form of individual hanger assembly drawing for each hanger tag

number. -

AUXILIARY STRUCTURES

0 Before taking up the erection of hangers and supports, the erection completion of auxiliary

structures required for hangers and supports shall be ensured. Depending upon the contract

agreement, materials for auxiliary structure will be supplied either by piping suppliers (Piping

Centre) or Purchaser (customer).

Q The location of each structure shall be checked for its position, elevation, orientation, etc.,

and recorded. It should also be ensured that they are conforming to the routing of the pipe line.

Q Ensure the size of structure and welding completion.

Q Ensure minimum head room for the erection of hangers.

Q Ensure that structural welding is carried out by qualified and certified welders.

Note : Auxiliary structures erected for pipe hangers by other agencies shall also be checked

for the above requirements.

Temporary Structures : Temporary structures are required to be erected for positioning,

aligning and arresting the aligned pipes in heights. In order to curtail deformation of pipes

during welding and to retain the alignment, the temporary steel arresters are required to be

given.

ERECTION

PROCEDURE FOR

HANGERS AND

SUPPORTS


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

Safe working platforms are also made by using temporary steel. However erecting the pipelines

on permanent hangers would reduce using temporary steel structure to a greater extent.

CONSTANT LOAD HANGERS

Introduction :

Constant Load Hangers (CLH) is one of the main supporting element in Piping Systems under

high temperatures.

CLHs are used to support piping where the thermal movement is very high during operation. In

order to maintain their accuracy, constant hangers are calibrated at works over their entire

working travel.

Features of the LISEGA design constant load hangers are :

0 Absolute constancy through the entire travel and load adjustment range.

Q A wide range of load adjustment makes it simple to readjust to new pipe line weights if

required.

Q Product range covers all possible client requirements. Q

Space savings achieved through simplified design.

Q Simplified installation procedure through symmetrical and light weight balanced design,

with single in line upper and lower load connection points.

Q Reusable blocking plate mechanisms enables the erection engineer to easily assess whether

the applied load is in conformity with the adjusted load of each hanger.

Q The use of pre relaxed springs with maintenance free bearings eliminates the need for

rebalancing of piping due to ageing of constant load hangers.

Construction Arrangement:

A robust flat steel housing encases the internal working parts. The compact arrangement of

individual components within the closed housing gives rise to a unit with small outside

dimensions thus allowing installation in the tightest of spaces. The housing is designed to be

load bearing and has been prepared for the acceptance of standardised connecting

components.

The constant load hangers can be placed directly on existing structure without additional parts.

Additionally however, special brackets can be attached to the existing connections.

ERECTION

PROCEDURE FOR

HANGERS AND

SUPPORTS


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

LISEGA Operating Principle : (Refer Fig.)

In order to fulfil the specified operational requirements, the LISEGA operating principle –

based on a parallelogram of forces – offers the optimum solution. The operating principle is

based on the interaction of the force of a main spring and the resultant force of two

precompressed compensating springs, the forces of which are opposed to each other in the

form of a paralleogram of forces.

ERECTION

PROCEDURE FOR

HANGERS AND

SUPPORTS


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

The suspended load (F) acts directly on the main spring (B) via a central load tube (A).

The force of the compensating springs (C) operate as a resultant force (F) through cams (D) and

the rotters (E) additionally on the load tube (A).

The main spring force (F1) and the resultant (F2) are changing over the travel range (S)

according to spring characteristic, angle and shape of cams.

As a result the power of the main spring can be compensated evenly and with mathematical

precision, thus providing a constant supporting force.

As the constant hanger is stroked in a downward direction, the interaction of forces can be

described in the upper, middle and lower position as follows ;

a As the rollers move down toward the apex of the cams, the compensating spring force acting

through them proportionally reduces. The corresponding main spring force increases.

a At the mid position the rollers are at the apex of the cams and their resultant is zero. At this

point only the main spring carries the load

a In the tower position the direction of the compensating spring resultant force is reversed and

now subtracts from the main spring force to produce the supporting effort.

a The sum or the difference between forces F1 and F2 is the same value at each point

ERECTION

PROCEDURE FOR

HANGERS AND

SUPPORTS


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

in the travel range resulting in a constant load carrying capacity during the whole

cycle of movement.

Load Adjustment: The LISEGA constant hanger principle of absolute theoretical constancy

has another significant advantage - an extremely wide load adjustment facility (from 40% to

100% of the nominal load) maintaining constancy throughout.

0 Load adjustment is carried out by adjusting the main spring pre-tension.

0 Since the characteristics of the resultant and main spring forces are identical only a linear

displacement of the starting load (F1) is obtained

0 The force variation attained by the main spring pre-tension is the same at each part of the

movement cycle and the supportive effort (F) therefore remains constant at each load

calibration setting.

The extremely wide load adjustment range available as a result of the LISEGA design principle,

enables us to offer a compact range of unit sizes.

Type Numbering :

The LISEGA type numbering system gives a complete identification of each standard product

by a unique four digit code. Constant hangers and supports are identified as follows :

Q 1st Digit: (Attachments and special features)

1 - Normal

2 - With ball bush for angulation

3 - Without lower connection plate

6 - With brackets supported from top

7 - With brackets and with lower connection plate

8 - With brackets and without lower connection plate

9 - With trapeze.

0 2nd Digit: (Product type)

1 - single cell

2 - two cell

3 - three cell

ERECTION

PROCEDURE FOR

HANGERS AND

SUPPORTS


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

4 - four cell

6 - support type

Q 3rd Digit: (Load group)

0,1,2.3,4,5,6,7,8,9 0 4th Digit:

(Travel group)

2for0- 150mm

3 for 0-300 mm

4 for 0-450 mm

5 for 0 - 600 mm

Erection Procedures: Q Ensure erection completion of auxiliary structures required for hangers erection.

Q Check the auxiliary steel structure size w.r.t. drawing.

0 Check the elevation of top of steel w.r.t. hanger schedule / drawing.

Q Ensure completion of welding of auxiliary structure and backing plate with auxiliary

structure.

Q Ensure the load connection points of the CLH to be connected are vertical to each other

in their operational stage.

Q Ensure that load anchors and connection points are frictionally connected and made safe

by lock nuts.

In general for CLH three types of top connections are envisaged. They are :

1. Threaded stud with eyenut.

2. Threaded stud with clevis and bolt.

3. Threaded rod with locknut or upper connection plate.

The bottom connection will be normally through loadnut in the case of single cell and lower

connection plate in the case of multi cell CLH.

ERECTION

PROCEDURE FOR

HANGERS AND

SUPPORTS


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

Upper connection with CLH : View through bottom of CLH if possible, to see that the threaded stud or threaded rod just

protrudes out to ensure minimum thread engagement. If not possible, ensure minimum thread

engagement by marking on the threaded stud or rod. Eyenut or clevis or locknut as the case may

be are to be tightened properly after connecting stud or rod to upper connection of CLH. If the

orientation of the eyenut or clevis is not as per requirement of hanger arrangement, then loosen

the eyenut/clevis, rotate slightly the threaded stud to the required extent such that after

tightening of eyenut / clevis the orientation will be in order and then tighten eyenut / clevis.

Lower connection with CLH : Ensure threaded rod reached beyond the small hole in the loadnut. Beyond the hole, the

threaded rod can go into the CLH upto 300 mm making it possible to adjust at site for head

roomupto300mm.

Erection Checks:

Q Check the model type and connecting components for its correctness as per drawing.

Q Ensure any offset is to be given while assembling the connecting components with the

spring.

Q Ensure the assembly of all the connecting components as per the arrangement drawing.

Q for 71 type (i.e. with side brackets) ensure that side brackets are either bolted or welded to

the structure.

Q After erection check whether ali the components are properly connected to each other.

Q Ensure that the CLH is in locked condition (the lockout shall be released only after the

hydraulic test).

Loading the CLH : (After Hydraulic Test)

CLHs are normally despatched from works locked at design cold travel position. After hydraulic

test the travel stop plates are to be removed. Travel stop plates should not be removed by force.

By loosening or tightening the load nut, the load on the travel stop plates can be released. The

geometrical position of the piping should not be changed during this operation.

ERECTION

PROCEDURE FOR

HANGERS AND

SUPPORTS


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

ERECTION

PROCEDURE FOR

HANGERS AND

SUPPORTS


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

Check the existing condition of CLH whether under loaded or over loaded by seeing the travel

stop plate and load bolt position.

Under load condition:

The load bolt will be forcing upwards i.e. the piping load taken by the CLH is less than the

set load (Fig. 2).

•Balanced state:

The load bolt will be in the middle position without touching the travel stop plate i.e. the travel

stop plate is free. This means that the piping load taken by the CLH is equal to the set load (Fig.

2).

Over load condition:

The load bolt will be forcing downwards i.e. the piping load taken by the CLH is more than the

set load (Fig. 2).

In the case of under loaded condition, the CLH is to be loaded by tightening the load nut (see

Fig. 2) so as to bring it to the balanced state. In the case of over load condition, loosen the

load nut and bring it to the balanced state and ensure that the toad bolt is free.

Once the load bolt is free, remove the travel stop plates on both sides and retain them for future

use by fixing them using bolt on the side of the CLH or on the top of the CLH depending upon

the hanger arrangement.

For bottom supported CLH ensure that it is fully loaded by checking the load bolt position.

The adjustment at one position may lead to stressing at other hanger position. Hence

this procedure has to be repeated several times to ensure all load bolts are free. For a

thorough control it is therefore recommended to remove the travel stop plates only after all

load bolts are free. This method of adjustment in all hangers ensures additionally that with all

load bolts free, installation based deviations of load distribution can be resolved.

ERECTION

PROCEDURE FOR

HANGERS AND

SUPPORTS


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

ERECTION

PROCEDURE FOR

HANGERS AND

SUPPORTS


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

Construction : A typical pipe work supporting system would employ variable spring hangers in conjunction

with constants (Fig. 3 & 4). According to requirements, spring hangers or supports can be

supplied to site without pre-setting or pre-set to the desired load for installation or blocked in

installation position.

In the case of pre-set spring hangers or supports, the spring plate is held in the desired position

by a Tee marked in red.

In the case of blocked hangers or supports, the spring plate is supported by a special blocking

piece in both directions in the casing slots.

All spring hangers are supplied with integrated travel scale. On the travel scale, the theoretical

operating postion is marked with a red sticker and the theoretical cold position is marked with a

white sticker. The position of the spring plate with the load set at the factory is marked with an

"X" on the travel scale.

Erection Procedure:

Q Ensure erection completion of auxiliary structures required for hangers erection.

D Check the auxiliary steel structure size w.r.t. drawing.

CI Check the elevation of top of steel w.r.t. hanger schedule/drawing. ,

0 Ensure completion of welding of auxiliary structure and backing plate with auxiliary

structure.

Q Ensure all connection points are properly connected and made safe by locknuts.

Q Set the cold value given in the contract documents for the respective tag numbers (SH1 to

SH9 for both 80 & 160 mm travel range).

Q Lock the hangers using hydraulic locknut and centering nut.

0 Punch the tag No., operating load and movement on the name plate as given in the contract

documents.

Q Mark the cold and hot setting positions on the travel scale with green and red paints

respectively.

ERECTION

PROCEDURE FOR

HANGERS AND

SUPPORTS


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

ERECTION

PROCEDURE FOR

HANGERS AND

SUPPORTS


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

Q For all other VSHs ensure the hangers are in locked condition at the cold values set at shop.

Top Type VSH During erection :

Q Apply required lubricant in between bearing plate assembly and spherical washer (See Fig.

5).

0 Remove turn buckle by taking out split pin and nut inside the turn buckle of the spring for

inserting the spring rod within the auxiliary supporting structure.

0 Erect the spring hanger such that the bearing plate assembly rests perfectly on top of

supporting structure.

Q Weld the bearing plate assembly with the supporting structure with 5 mm fillet. Q

Assemble back the turn buckle with corresponding nut and split pin.

After Hydraulic Test:

All hangers shall be unlocked by loosening hydraulic locknut and centering nut as per the

following steps.

Q Remove top nut (at the top) from the top tie rod.

Q Loosen hydraulic lock nut and then centering nut.

Q Remove hydraulic lock nut and centering nut from the top tie rod.

Q Then assemble centering nut, hydraulic lock nut and top nut in the same sequence, such

that the hydraulic lock nut is held between centering nut and top nut and the distance

between the free end of top tie rod & top of nut shall be approximately 5mm.

Bottom type VSH

During Erection :

While locating the spring hanger in position, the following steps shall be followed (See Fig. 6):

Q Reduce the overall height of the spring hanger by 5 to 10 mm, by rotating the disc. Q

Insert the spring hanger in position.

Q Rotate the disc until it is in full contact with the corresponding attachment to

pipe. 0 Bring down the locknut such that it is in contact with the spindle pipe.

ERECTION

PROCEDURE FOR

HANGERS AND

SUPPORTS


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

ERECTION

PROCEDURE FOR

HANGERS AND

SUPPORTS


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

After Hydraulic Test:

Q Release the hydraulic locknut and screw it on the threaded portion below the disc. 0

Release the centering nut to the top most possible point.

Note: Ensure all the spring hangers are in locked condition at the cold set toad alredy done at

shops before hydraulic test.

RIGID STRUTS :

In general, rigid struts are used for pipe restraints where dynamic loading is envisaged. It is

meant for taking compressive loads. Rigid struts are connected through weld on bracket, bolt on

bracket etc. (See Fig. 7).

Erection Procedure:

Q Clean the bearing surfaces of the rod ends thoroughly. d Ensure weld on brackets or bolt

on brackets are welded to the supporting structures.

0 Adjust the overall length of the rigid struts before erecting in position, while doing the

following:

0 Measure the distance between the centre lines of pins of weld on brackets or bolt on

brackets erected to the supporting structures and pipe attachments.

0 Loosen the locknut of rigid strut on either end.

d Adjust evenly by rotating the rod ends on either ends (one rod end is with RH thread and the

other with LH thread) to the actual distance measured.

Q Bring the rigid strut in position and fix it on one end. If required, minor adjustments can be

made to fix it on the other end.

0 Ensure minimum thread engagement on either ends as in indicated in the figure.

Q Tighten the locknuts.

ERECTION

PROCEDURE FOR

HANGERS AND

SUPPORTS


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

Note : Avoid welding weld on brackets with the rigid struts assembled to the

brackets. This may cause damage to the spherical bearing due to heat generated during

welding.

SHOCK ABSORBERS : Shock absorbers supplied by BHEL are generally hydraulic version. These shock absorbers

become active onfy when dynamic action is initiated due to shock loads. In normal operating

conditions, these are not taking any load and allow the piping to move freely to accommodate

thermal expansion of piping.

ERECTION

PROCEDURE FOR

HANGERS AND

SUPPORTS


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

Prior to erection of shock absorbers, ensure the orientation of brackets in such a way that the

maximum angle of transverse in the direction of the largest operational thermal movement.

Erection Procedure :

Q Ensure correctness of all the components.

Q Ensure all connecting components are erected properly to avoid any looseness in the

connectivity between structure and the supporting point.

Q Ensure sufficient travel is available in the shock absorber assembly after erection for the

piping to move freely.

CONNECTING COMPONENTS : The following are the connecting components which are normally used in the erection of

hangers and supports.

Tie Rods:

Calculate the length of tie rod required considering the erection tolerances of structure/piping

and the minimum projection length of threaded components.

Then cut the tie rod to the required length either on one side or on both sides as required by

hacksaw or machining. (No gas cutting is allowed).

Smoothen the cut ends of threaded portion.

Ensure that the threads of tie rod are fully engaged with the matching components.

Ensure the hanger is in stiff condition after erection.

Lock the tie rod with the connecting components using the locknut.

Note: In the case of rod couplings, locking nuts are provided on both sides. This means two

locking nuts for each rod coupling.

Rod Coupling: Rod coupling is meant for building up the length of tie rods (Fig. 9).Tie rods on both the ends

are to be screwed evenly inside the rod coupling to the maximum length as shown in figure.

ERECTION

PROCEDURE FOR

HANGERS AND

SUPPORTS


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

ERECTION

PROCEDURE FOR

HANGERS AND

SUPPORTS


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

This should be ensured through the sight holes of 5 mm size provided at the centre of the rod

coupling.

In case sight holders are not provided in the rod couplings, due care has to be taken to ensure

full engagement of rods upto the centre of rod coupling (by making white paint on the tie rod

before assembling with the rod coupling).

Weld on Clevis: Weld on clevis (Fig. 10) shall not be interchanged with clevis with bolt or weld on bracket or

bolt on bracket.

The minimum weld size as given in Fig. 10 shall be ensured all round the four sides since this

weld is taking full load of the hanger.

While welding the clevis, following points shall be taken care of:

Q Ensure the surfaces to be welded is free from paint, grease, metallic coating, scale, rust etc.

Q Remove the pin from the clevis. Q Ensure proper seating of the clevis with structure or

other connecting component.

Q Preheat the clevis to about 100 degrees centigrade (for clevis with base plate thickness

more than 20 mm).

Q Await cooling of clevis to about 100 degrees centigrade after each layer. Q

Apply the seam in multi layers to avoid deformation due to welding. Weld on Bracket:

Weld on bracket (Fig. 11) shall not be interchanged with clevis with bolt or weld on clevis or

bolt on bracket.

The minimum weld size as given in Fig. 11 shall be ensured all round the four sides since this

weld is taking full load of the hanger including dynamic loads.

While welding the bracket to the structure or other components, the following points shall be

taken care of:

ERECTION

PROCEDURE FOR

HANGERS AND

SUPPORTS


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

ERECTION

PROCEDURE FOR

HANGERS AND

SUPPORTS


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

Q Ensure the surfaces to be welded is free from paint, grease, metallic, coating, scale, rust etc.

Q Remove the pin from the bracket. Q Ensure proper seating of the bracket with the

structure or other connecting component.

0 Preheat the bracket to about 100 degrees centigrade (for brackets with base plate thickness

more than 20 mm).

Q Await cooling of bracket to about 100 degrees centigrade after each layer. 0

Apply the seam in multi layers to avoid weld deflections.

Bolt on Bracket is similar to the weld on bracket, except the connection is through bolts and

nuts. The nuts shall be tightened evenly.

Pipe Clamps: Pipe clamps are the components which ensure the connectivity between the pipes and the hanger

components. Following are the different types of clamps designed for various and applications.

Q 3 hole clamps

Q Riser clamps

Q U rod clamps for small bore piping / non critical piping

Q Bearing clamps for bottom supports

Q Special clamps for dynamic loading

Q Trunnion clamps

The clamps are unique in design and hence should not be interchanged, though they may look

similar. Even among the standard clamps, it is not preferable to interchange the parts of one

assembly to another.

ERECTION

PROCEDURE FOR

HANGERS AND

SUPPORTS


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

Erection Procedure :

Three hole clamps:

Q Ensure that the pin in the clamp assembly taking the load is outside the insulation.

Q Ensure that the spacer plate / rings are assembled in the correct place to provide the

necessary gap for introducing mating components like connecting plates, eyenuts, etc.

Q Ensure the spacer ring is inserted on the stud near the load pin and on the stud which is

below the pipe for three hole clamps.

Q For three hole clamps, tighten the nuts on the stud near the load pin and then on the stud at

the bottom of the pipe.

Q Ensure verticality of clamps. Riser

Clamps:

Q Ensure the orientation of the clamp is given in the hanger data sheet.

Q Ensure that the riser clamps have a direct contact with all the carrier plates welded with

pipe.

Note : If the contact is not available, then the carrier plates are to be ground carefully such

that they are in the same level and in direct contact with the clamp assembly when loaded.

Q Ensure carrier plates are at 45 degree from the partitionn plane of the camps.

Whenever site welding is indicated for the carrier plates of riser clamps, the following points

shall be taken care of at site.

Q Weld the carrier plates such that they are in the same level at the contact surfaces with

the clamp.

Q After welding on one side of the carrier plates, the other side shall be back gouged to

sound metal and tested by MPI / LP1 before welding the other side.

Q Ensure that no weld metal projects outside the carrier plates at the surface of contact

with the pipe clamp.

ERECTION

PROCEDURE FOR

HANGERS AND

SUPPORTS


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

ERECTION

PROCEDURE FOR

HANGERS AND

SUPPORTS


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

Q Ensure that preheating and PWHT requirements as required for the material used are

carried out.

Trunnion Clamps :

Q Ensure the following before tag welding of plate with box (Fig. 13).

Q Uniform gap between plate hole and trunnion along the circumference as shown in Fig. 1

.This could be ensured by inserting thin sheets of suitable thickness or wires of suitable diameter

at three places 120 degrees apart.

Q Parallelity of the two plates by measuring the inner surface to inner surface dimension at

the four comer points (1) - (4) of the plates marked in the drawing. All the four measurements

shall be to the dimensions given in the drawing taking into consideration the tolerance.

Q Ensure rotation of clamp about trunnions before final welding of box to plate.

0 Location of weld-on bracket shall be as indicated in drawing. Orientation of weld-on

bracket shall be as per the guidelines given in the Erection Notes for Piping Hangers and

Supports.

ERECTION

PROCEDURE FOR

HANGERS AND

SUPPORTS


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

QUALITY CHECKS Q Each hanger assembly shall be verified against the hanger documents to assure that all

components have been installed and are in their proper position. This includes

temporary hangers and supports required for hydraulic test.

Q Check threaded components of each hanger for proper and full length thread

engagements and locked.

Q Ensure Constant Load Hangers (CLH) and Variable Spring Hangers (VSH) are erected

as per hanger tag numbers punched on them.

Q Ensure that CLH & VSH are not interchanged.

0 Ensure all hanger assemblies have been properly installed, adjusted and loaded as per

hanger drawings.

Q After completing hanger installation, ensure that locking nuts on threaded components

are locked security in place and split pins, washers, nuts etc., are intact.

Q Ensure sliding supports using Teflon, graphite, stainless steel sheets, steel to steel plates

etc. are in position as per hanger documents.

Q Ensure all sliding surfaces are free from foreign matter and free from weld/metal

projections.

Q Ensure locking pins/travel stops, temporary, supports etc., are removed after completion of

hydraulic testing of piping system.

Q Ensure adjustments are made for cold position given in the hanger documents for CLH.

Q Ensure the orientation of the hangers such that the load / travel scales are at convenient

position for reading.

Q Ensure that all components connected to the clamps are outside the insulation. Q

Ensure that all intermediate floating beams are in horizontal position.

ERECTION

PROCEDURE FOR

HANGERS AND

SUPPORTS


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

DO's and DONT's :

DOS :

Q Check if adequate space is available for installation and maintenance of hangers.

Q Check and clean spring cage and constant load hanger assemblies before erection with

compressed air.

Q Erect hangers before pipe line preferably wherever pipes and hangers are available.

Q Ensure all threads of turnbuckle are engaged with tie rods. Enough preset gap should be

available in turn buckle for future adjustments.

Q Suspend suitable counter weight at each hanger location to compensate absence of liquid

and insulation. Remove when line is insulated and filled with service liquid.

Q Keep hanger assembly vertical in cold if swing in the hot is not more than 4 degrees with

the vertical.

Q Offset suspension point suitably to limit swing in the hot to 4 degrees in case otherwise

swing in the hot is expected to be more than 4 degrees.

Q Lock all spring hangers prior to hydro-test. 0 Remove temporary supports

if any before cold setting of hangers.

Q Unlock the hangers as soon as hydro test is over after draining the water and set them to

their cold values after application of insulation, where specified.

Q Mark the hanger numbers with paint.

Q Ensure the hangers are set to their cold set values after completion of insulation and before

charging the lines.

Q Install shock absorber in the last, after completion of entire pipe line and its hanger. Q

Follow installation procedure of supplier.

Q Watch and record free thermal movement of pipes and hangers. Compare hanger values is

not condition with design values.

DONT'S :

Q Dont' charge the line with hangers in locked condition.

Q Do not remove lock pin from spring hangers before hydro-test or chemical cleaning is over.

ERECTION

PROCEDURE FOR

HANGERS AND

SUPPORTS


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

PRE-ERECTION AND

ERECTION PROCEDURE

AND CHECKS OF PCP


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

PRE-ERECTION NOTES :

1. A. IBR formalities / clearance to be taken before starting up work.

B. The necessary form 111C, or despatch inspection report are required from

respective manufacturing unit before starting the work.

2. The materials punch mark details are to be checked with drawing and verified. If colour

coding is there cross check up with colour coding.

3. Chek the D 1 diameter of both ends any damage on the ends noticed Grinding / Weld and

correct the edges by welding with necessary procedure pre heating / post weld heating.

4. The necessary W.P.S. can be selected from the W.P.S. supplied by respective regions.

5. Pre-assembling joints and completion of X-ray and stress releaving in ground level should

be completed for best results with easy movability. Any repair is identified in X-ray, correct it at

pre assembly stage itself. The locking arrangements for welding to be kept until stress releving

process is completed.

6. Joint identifications in A4 drawing sketch for each pipe lines.

7. Starting point / ending point X,Y,Z co-ordinates to be checked be checked with respective

to drawing and ensure the coorect co-ordinate with available points. any variation noticed enter

in the protocol with respective agencies.

8. The routing of pipe lines inside boiler area, T.G.G. hall entry, and routing inside T.G. hall

are to be checked for any possible fouling of line with brazing, structures. If any fouling noticed

take up respective agencies to correct structures and this will help us in carrying out work with

less interfrence and at the same time other agencies to correct their points

9. The routing of pipe crossing the floor are to be checked for proper opening in the floors.

The PEM/Consultants layout drawings to be refered for the above areas. Any floor opening to

be done informing respective agencies for necessary correction.

PRE-ERECTION

& ERECTION

PROCEDURES &

CHECKS


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

10. The hanger points are to be checked for the accomadation of auxiliary structure

& pipe hanger assembly. Any correction to be incorporated where required

Inconsultation with Designer.

PRE-ASSEMBLY :

1. Before taking up pre assembly, the Orientation of supports, carrier plates and bunion pipes

for supports arrangement locations are to be checked with respect to hanger location/These

specific details are available in PEM/Consultants Drawing.

2. The necessary mechanical method to be adopted for ensuring the clearing of pipe before

matching it.

3. Any anticipated delay is expected in completion of welding Aluminum Deoxide paint to be

provided for Rust prevention.

4. a. The welder identification and joint identification to be punched on the pipe near to

joint for future reference purpose.

b. The fit up to be done as per the details given in W.P.S. / Welding

Schedule. The correct electrode and process parameters are to be taken from

WPS / Welding Schedules.

c. The necessary temporary supports are to be provided out before welding and the

supports are to be kept until stress relieving is over. The necessary

temperature details can be taken from welding schedules.

d. The Gamma plug welding to be completed after Radiography work completion.

e. The necessary repair work if any correct it at pre assy stage . f. After

S.R. the supports are removed and cleared for erection.

g. The necessary welding log, NDT, repairs and SR records to be maintained. Refer

welding manual for further reference.

* For X20/P-91 refer separate procedure.

PRE-ERECTION

& ERECTION

PROCEDURES &

CHECKS


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

ERECTION OF PIPELINES :

Erection of pipelines consisting of four parts

A. Rigging arrangements for pipes.

B. Erection of permanent hangers

C. Erection and alignment of pipes.

D. Removal of temporary supports after welding and stress -relieving.

A. 1. Rigging arrangement for pipes are as follows, - Identify the Du's which can be

erected by winch, crane, EOT crane and chain blocks.

2. Identify temporary system for supporting the pipes for lowering and welding purpose.

3. Identify the items coming inside the TG Hall area, boiler area and in between boiler and

TG Area.

4. If any rack piping is to be done ensure the proper expansion loop arrangements in the rack

system and necessary supporting for loops.

5. Any one of lifting arrangements can be identified for erection of the system.

6. The Rigged pipe can be put in the location or near to the location by proper lashing or

temporary supports.

B. ALIGNMENT OF PIPES AND WELDING, NDT & STRESS RELIEVING :-

ERECTION OF PERMENENT HANGER SUPPORTS. (REFER HANGERS AND

SUPPORT FOR FURTHER DETAILS)

1. The pipes are to be erected with permanent hangers to the maximum extent

possible so that weight of the pipes will be taken care by permanent supports.

PRE-ERECTION

& ERECTION

PROCEDURES &

CHECKS


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

2. Use minimum nos. of temporary supports for alignment of pipe for welding stress relieving

and; stress relieving Purpose.

For Alignment of Pipe, use pipe clamp arrangement with adjusting screw to

get proper alignment for welding

3. By adopting step 1,2 we can reduce the temporary system of supporting to a great extent.

The idea is to keep minimum amount of temporary supports which will consume lot of man

power in latter stage for removal.

4. Ensure the negative slope in the line. If drawing, specify the slope adjust for it.

5. The necessary stress relieving and NDT requirement are to be taken careof.

6. ' The necessary welding log and NDT, S.R. Log sheets are to be maintained.

7. The checkup drain points and vent points are to be checked up

8. Interact with customer for installing drain lines valves for operating convenience.

9. The drains are to be taken upto 0 mtrs or at required elevation or system requirement

depending upon contract requirement.

10. After completion of vent points. Visual inspection of fillet weld drains to be carried out for

any visible defects. If anything identified correct it.

11. Alongwith customer go for erection of hanger supports and necessary cold value setting.

Ensure the hangers are in locked condition. Ensure that the RIGID STRUT points are erected in

proper orientation.

12. All hangers are to be locked before hydro test.

GET ALL NDT AND S.R. CLEARANCE FROM THE BOILER INSPECTORATE BEFORE

WATERFILLING :

13. Check the water chemistry before fill up water for hydro test.

PRE-ERECTION

& ERECTION

PROCEDURES &

CHECKS


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

14. Fill up the water and pressure the system for required hydro test pressure.

Identify the leakage point, correct it, after draining the system .

15. Do the hydro test and ensure the leak proof system.

16. Get the hydro test clearance from statutory authorities. Make protocol for the

above systems.

17. Ensure proper usage of calibrated pressure gauge.

18. Drain the water system and clear it for insulation after removing temporary

supports.

19. After hydro test is over release for insulation and release the hanger locking and

proper loading to be done as per hanger schedule.

PROCEDURE FOR NORMALISATION OF BFP PUMP

1. After Alkali Flushing of the BFP / Pre Boiler System the temporary connections are

removed and the edges of pipe lines are to be ground for matching the joints.

Following are coming under normalisation work.

The Balance portion of line between Feed Pump to NRV to be completed after floating of the

BFP System. For floating of lines kindly refer the portion, "floating of pipe lines" Ref. 08—03/5

of 5.

Record the cold values of hangers. After welding stress relieving and radiography remove the

temporary supports and keeping pump as main point re-adjust motor and fluid coupling system

and complete the alignment. Ensure the cleanness of pipe each step. other wise it may cause

pump to seize. Finally release the system for running.

PRE-ERECTION

& ERECTION

PROCEDURES &

CHECKS


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

INTRODUCTION OF FULL LOAD CONTROL VALVE / VALVES:

The control valves are introduced after completion of flushing activity. The distance between

two ends are measured and grind it to match with ends and ensure the cleanness of pipes before

pipe welding. Complete the welding and Stress relieving and required NDT requirements.

Introduction of Flow Nozzle / orifices:

Location of flow nozzle and orifices are identified in pipe line. Lock the pipes with temporary

supports before cutting to a oid unnecessary pipe movements. Refer the flow nozzle

introduction procedure by Piping Centre / Chennai document for further procedure. After

completion of welding / NDT / Stress relieving remove the temporary supports and the system

is released for operation.

If the system to be under going for Hydro Fluric acid cleaning in certain projects then MS Line,

CRH, HRH, LPBP, up stream and down stream are to be included in HF cleaning system.

Kindly refer the pipe cleaning system separately available. This cleaning requires separate pump

and temporary systems which are to be erected and cleaning to be done. If the Boiler cleaning

system is available the same can be converted for this cleaning purpose.

After completion pipe cleaning & steam blowing arrangements are to be done for various pipe

system. A separate pipe line and valve is to be erected for cleaning the system by blowing.

* * * *

* * * * * * * *

Control Valves

If the control valves are A Frame type mounted as shown above, a separate Hydrotest

attachment is available along with valve for carrying Hydro-test and steam blowing. Use the

steam blowing attachments for the valves and attach the balance portion temporary system of

pipe lines for carrying out steam blowing activity.

PRE-ERECTION

& ERECTION

PROCEDURES &

CHECKS


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

If ESV valve of main steam line is body mounted the temporary line to be taken from turbine

end with a separate arrangement supplied along with valve for steam blowing purpose.

The pipe lines between control valve / NRV to turbine, both in HUH and CRH, MSL lines to

be floated before welding to turbine end. For this separate chapter is given for floating of the

pipe lines.

After completion of steam blowing the following normalisation works are to be taken up:

The following works are considered to be normalisation work:

1. Introduction of break down orifice in Hp BP down stream.

2. Normalisation HP BP system

3. Introduction of control valves, flow nozzle

4. Re routing of drain lines to flash tanks.

5. Fitting of strainer elements in MS HRH

After the lines are over the system is allowed for further process, once the system is started

functioning check the load values of hanger at full parameters and record the Hot values and

no. of hangers and send to PC/ Chennai.

HYDRO TEST DUMMIES :

During erection of pipe lines we may require to dummy certain lines for hydro test. The

following are the guide lines given for calculating Hydro test dummy thickness:

Formulae for Flat dummies:

T = d p x k + e

s

t = Minimum thickness required for end closure

d = Internal die of connecting pipe

p = Maximum working pressure kg / cm2

PRE-ERECTION

& ERECTION

PROCEDURES &

CHECKS


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

k = 0.28 e = 1 mm

s = allowable stress: for carbon steel dummies

Boiler quality steel = 1230 / kg/cm2

For e.g. pipe line 457.2 x 16 mm Thick, pressure 34 kg Dummy

is as follows

t = 427.7 34 x 0.28 + 1 1230 = 38.62 mm The hydro test pressure = 1.5 x

working pressure

The design pressure for 34 kg / cm2 is to be hydro for 34 x 1.5 times as per the requirement.

The above procedure is drawn for guidance to the Erection of critical piping. For non ortical

lines, non IBR lines, IBR requirements and floating may not be required.

For Auxiliary lines coming under IBR purview IBR formalities to be followed.

PRE-ERECTION

& ERECTION

PROCEDURES &

CHECKS


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

1. NORMALLY, BHEL PC SUPPLIES THE FOLLOWING C&I ITEMS. 1.1 Gauges (Pressure, Temperature, Level, Sight Flow, Differential Pressure)

1.2 Switches ( -do- )

1.3 Transmitters ( - do - )

1.4 Flow Elements

1.5 Control Valves

1.6 Local Penumatic Controllers

1.7 Supervisory Control Panels

1.8 Electrical Heat Tracers and Accessories

1.9 Power Distribution Panel (EHT)

1.10 Cables and Cable Laying Accessories

1.11 Field Junction Boxes

2. AVAILABILITY OF FOLLOWING DOCUMENTS SHALL BE CHECKED 2.1 Packing List/Shipping List

2.2 Instrument Schedule and List of Transmitters

2.3 Instrument Installation drawings

2.4 Panel General Arrangement and Foundation drawings

2.5 Interconnecting Cable Schedule

2.6 EHT Layout drawing

2.7 EHT Installation Manual

2.8 Individual Instrument O&M Manual

Ref: 81-400 Series w.r.t. Instrumentation

80-900 Series w.r.t. Control Vales

GUIDELINES

FOR ERECTION

OF C&I


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

3. CHECKS FOR BHEL PC SUPPLIES C&I ITEMS 3.1

Local Gauges

3.1.1 Tag number, gauge type, size, range, process/instrument connection,

installation conform to requirement (Refer PIDs, Instrument Schedule).

3.1.2 Instrument piping connection to gauges (Refer Instrument Installation

drawing).

3.1.3 For different pressure gauges, check that the process line with higher static

pressure is connected to the connection marked "HIGH" or "F" or "P" of the DP

instrument and the process lie with lower static pressure is connected to "LOW"

or"-" mark of DP instrument (Refer Instrument Installation drawing).

3.2 Local Switches 3.2.1 Electrical connection to the switch/micro-switch (Refer interconnecting cable schedule).

3.2.2 Free movement of switches by manual tilting.

3.2.3 Instrument piping connection to switches (Refer Instrument Installation drawing).

3.2.4 Check for flow direction mark onflow switch (medium flow left to right or right to left or

top bottom or bottom to top).

3.3 Transmitters 3.3.1 Tag number, transmitter type, range, process/instrument connection tapping (Refer list

of transmitters).

3.3.2 Proper mounting of instrument (Refer transmitter installation drawing).

3.3.3 Instrument earthing (Refer O&M manual and multimeter).

3.3.4 Routing of impulse pipeline and gradients (Refer installation drawing).

3.3.5 Supply voltage/instrument air availability (Refer O&M manual, use multimeter and

instrument installation drawing).

3.3.6 Leak proofness of fittings.

3.3.7 For DP transmitter, process line with higher static pressure connected to the connection

marked "HIGH" or"+" on the transmitter and the process line with lower static pressure is

connected to the connection marked "LOW" or"-" on the transmitter.

GUIDELINES

FOR ERECTION

OF C&I


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

3.4 Panels

3.4.1 Foundation details (Refer GA/foundation drawing of panel and use measuring tape).

3.4.1 Verticality of panel (use plumb).

3.4.3 Function of panel door (for opening, closing and locking of panel door).

3.4.4 Seggregation of power, control, signal and pre-fabricated cables (Refer cable schedule,

panel internals drawing).

3.4.5 Cable size, termination and inter-connection between panels/cubicles/cabinet/control

desks/MCC/JB (Refer cable schedule).

3.4.6 Earthing of panels (panel drawing, use multimeter).

3.4.7 Unused cable gland holes shall be plugged. 3.5 Flow Elements (orifice plate/flow

nozzle)

3.5.1 Number, size and location tappings (Refer RE data sheet, F.E. assembly drawing).

3.5.2 Flow direction (flow direction marked on flow element assembly).

3.5.3 Gradient/connection of impulse pipes and installation of condensing/cooling vessels

(Refer F.E. installation drawing).

3.5.4 Welding of F.E. assembly, hydraulic test after installation of F.E. assembly (Refer F.E.

general arrangement drawing).

3.5.5 Purging of pressure tappings.

3.6 Control Valves (Electric / Pneumatic)

3.6.1 Name plate details and type of mounting.

3.6.2 Supply/signal air connection, AFR setting quality of compressed air (Refer C.V.

hook up drawings, use receiver gauge).

3.6.3 Mounting of C.V./actuator accessories like position limit switches, torque switches,

I/P converter, solenoid valves, position transmitter etc. (Refer C.V. hook up

drawing).

3.6.4 Cable terminations (Power cables and control cables - Refer Actuator terminal block

disposition).

3.6.5 Free movement of actuator over its complete range of travel in both "OPEN" and

"CLOSE" directions to be checked manually (Refer O&M manual).

GUIDELINES

FOR ERECTION

OF C&I


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

3.6.6 Supply voltage to motor and control circuit terminals (use phase sequencer and

refer actuator terminal block disposition diagram).

3.6.7 Earthing of actuator (use megger).

3.6.8 Check size of cables and cable glands (use verniers).

3.6.9 Proper matching of actuator flange with valve flange (Refer C.V. drawing).

3.6.10 Tightening of all fasteners (use torque wrench).

3.7 Junction Boxes

3.7.1 Type, material and no. of ways (Refer JB schedule).

3.7.2 Cable Terminations (Refer interconnecting cable schedule).

3.7.3 Gasket for tight closing of JB.

3.8 Cables and Cable Accessories

3.8.1 Material and dimension of cable tray (cable tray drawing).

3.8.2 Glanding, dressing and clamping of cables.

3.8.3 Cable continuity and insulation resistance (use megger).

3.8.4 Cable conductor material, type of insulation, cable dimension, no. of cores (Refer

cable interconnection cable schedule).

3.8.5 Proper termination

3.8.6 Voltage and current rating (Refer cable data sheet /O&M manual).

3.8.7 Seggregation of power and control cables.

3.9 Local Pneumatic Controller

3.9.1 Dimensions (controller general arrangement drawing).

3.9.2 Mounting (Refer PID, controller and installation drawing).

3.9.3 Air connection, AFR setting (Refer controller installation drawing, use air receiver).

3.9.4 Process connection (Refer instrument schedule of controller general arrangement

drawing).

GUIDELINES

FOR ERECTION

OF C&I


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

3.10 Electrical Heat Tracers and Power Distribution Panel 3.10.1 Tracer routing (Refer layout drawing).

3.10.2 Installation of tracers (O&M manual).

3.10.3 Powering of tracers (Refer circuit schedule).

3.10.4 Power and control cables to tracers (Refer circuit schedule).

3.10.5 Avoid cross-overs between tracers.

3.10.6 Use of adhesive tape over tracers to achieve maximum contact.

3.10.7 Location of Power Distribution Panel (Refer EHT scope drawing).

3.10.8 Panel foundation (Refer panel general arrangement drawing).

3.10.9 Power/control cable termination (Refer circuit schedule and panel TB disposition

drawing).

3.10.10 Transformer rating of panel (Panel general arrangement, O&M manual).

3.10.11 Cable entry to panel (Panel general arrangement drawing).

3.10.12 Other checks on panel (similar to cl. Listed earlier).

GUIDELINES

FOR ERECTION

OF C&I


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

1.0 SCOPE : The procedure deals with hydraulic test of piping system erected at site. The exact

Hydraulic test procedure to be followed depends on local job site conditions. The

procedure outlined below is general in nature.

2.0 PREPARATIONS FOR THE TEST :

2.1 SYSTEM COMPLETION :

Prior to hydraulic testing, the following items shall be inspected.

a) All necessary welds completed, radiographed and heat treated.

b) All necessary valves including drain valves installed and closed.

c) All safety valves installed and hydrostatic plugs assembled before commencing the test.

d) The drain valve and test valve in the official calibrated pressure gauge sensing line is open.

e) All vents necessary to prevent air entrapment during filling operation shall be kept open.

f) When valves are in. TANDEM (double valved) both valves must be closed during the

hydraulic test.

g) Joint protocol prepared prior to hydraulic testing of the system to be duly filled up.

2.2 AIR TESTING OF THE PIPING SYSTEM :

1. Before filling the system with water an air tightness test is to be performed to detect

leakages due to valve left in open position, radiographic plug not in position, any cuts or gouges

etc. not observed by visual inspection. This will reduce the water consumption, as well as time.

2. The air shall be filtered and free from oil and dust prior to entering the system

3. The system is to be pressurised not more than 2 Kg I sq.cm

HYDRAULIC

TEST PROCEDURE

FOR PIPING


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

4. Before admitting air, close all the isolating valves in drain lines, branch lines

and vent lines including the vent valves and test valves in official pressure gauge etc.

5. After completing the air tightness testing keep the vent valves, drain and test

valves in official pressure gauge in open position.

2.3 AVAILABILITY OF WATER AND QUALITY: It is the responsibility of the customer lo provide properly treated water, as specified below at

ambient temperature but in no case less than 20°.

Note : a) The temperature limitation for hydraulic testing is 70 degree F or 21 degree C.

The important point is that the hydraulic pressure should not be applied when the

water temperature is less than this limit.

b) During testing, the temperature of water should in no case exceed 50° C.

0 It is recommended to use demineralised or condensate quality water of specified purity for

the entire piping, system, which includes non-drainable RH coils connected to RH piping.

Q Quality of Treated DM water or Treated Condensate: The DM water or condensate

shall be treated with 10 ppm Ammonia and 200 ppm Hydrazene to have a pH value of

approximately 10.

Note : Demineralised or condensate quality water is defined as containing not more than 1 ppm

identifiable solids and essentially a zero concentration (or lowest detectable level) of organic

materials.

2.4 PRESSURE GAUGES :

a) During testing, atleast two properly calibrated pressure gauges are to be located,

one at top level and one near pressurising pump.

b) The indicator of the pressure gauges selected shall have atleast 6 inches dia with

HYDRAULIC

TEST PROCEDURE

FOR PIPING


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

dials graduated over a range of double the intended test pressure, but in no case the

range be less than one and half times that pressure.

2.5 FILLING PUMP AND PRESSURISING PUMP WITH

TEMPORARY CONNECTED PIPE LINES

2.5.1 PUMPS:

a) Check for correct direction of rotation of fill pump.

b) Open air vent of the pump during start-up' if applicable.

c) Check motor current at no load as well as at full load conditions. Check whether a correct

fuse is introduced in the circuit to avoid damages to the motor

d) Before starting the filling pump, the delivery valve to be closed and the suction valve kept

opened . Then open delivery valve gradually for filling. Before stopping the pump delivery

valve should be closed

e) Before starting the pressurising pump it should be ensured that the delivery valve is kept

open

2.5.2 CONNECTED PIPELINES (TEMPORARY)

a) Shall all be welded.

b) Delivery line of pressurising pump shall be of high pressure seamless pipe to with stand

the required test pressure.

c) Mixing tank should be of required capacity, wherever applicable.

d) Flow regulating valves, drain valves, over flow lines should be provided with the

mixing tank.

2.6 TEST PRESSURE : The lines shall be hydraulically tested as per drawing. Normally, the hydraulic test

pressure shall be one and half times the design pressure.

HYDRAULIC

TEST PROCEDURE

FOR PIPING


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

3.0 LIMITS OF HYDRAULIC TEST

3.1 MAIN STEAM LINE :

The hydraulic test of main steam line up to boiler main steam stop valve shall be done

along with boiler.

The hydraulic test of main steam line between MS stop valve and turbine shall be

done as follows:

3.1.1 ISOLATING DEVICES/TERMINAL POINTS ARE AS FOLLOWS :

a) MS stop valve on boiler side.

b) Emergency stop valve cum regulating valve on turbine side.

c) HP Bypass line from MS line upto HP Bypass valve.

d) Blanking of HP bypass upstream near HP bypass valve.

e) Isolating valves in steam line to Aux. PRDS station.

3.1.2 CHECKS : 1. The line may be filled up and pressurised through lowest drain line of piping (permanent or

temporary) system.

2. Before hydraulic test, all the hangers shall be locked. After hydraulic test the locking shall

be released.

3. Vents / drains / local remote impulse lines I integral bypass valves / radiography plugs at

selected locations in this piping system to be judiciously used for filling / venting / draining.

The details to be worked out at site as per the piping scheme.

4. Test the line to hydraulic test pressure as per drawing requirement.

5. After successful hydraulic test the line may be drained and released for normalisation.

3.2. COLD REHEAT LINE :

The cold reheat line is hydraulic tested from NRV near turbine to desuperheater inlet.

HYDRAULIC

TEST PROCEDURE

FOR PIPING


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

3.2.1 ISOLATING DEVICES / TERMINAL POINTS ARE AS FOLLOWS

a) NRV to be removed and spool piece to be provided. Blank CRH line near turbine by

removing bent piece. Give one vent point at that end of CRH line.

b) Blank HP bypass downstream line at the place of HP bypass valve end.

c) Blank CRH line at the end of spool number C-53 and C-64 before DESH.

3.2.2 CHECKS :

1. The line may be filled up and pressurised through lowest drain line of piping (permanent or

temporary) system.


be released.

3. Vents I drains /. local remote impulse lines I integral bypass valves / radiography plugs at

selected locations in this piping system to be judiciously used for filling I venting / draining.




3.3 HOT REHEAT LINE : Hot reheat line is hydraulically tested from interceptor valve on turbine side to blanks

on spools H4 and H29.

3.3.1 ISOLATING DEVICES / TERMINAL POINTS ARE AS FOLLOWS :

a) Interceptor valves on turbine side.

b) Blanks on spools H4 and H29 (at CRH line end).

c) LP bypass valves.

d) LPBP warm up line.

HYDRAULIC

TEST PROCEDURE

FOR PIPING


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

3.3.2 CHECKS : 1. line may be filled up and and through lowest drain drain of piping (permanent or

temporary) system.


be released

3. Vents / drains / local remote impulse lines / integral bypass valves /• radiography plugs at





3.4 BOILER FEED DISCHARGE LINE :

The boiler feed discharge line is hydraulically tested from feed pump isolating valve

to economiser inlet isolation.

3.4.1 ISOLATING DEVICES / TERMINAL POINTS ARE AS FOLLOWS :

a) Economiser inlet isolation valve

b) Isolation valve in spray water line to HP bypass valves.

c) Providing dummy in SH / RH spray lines.

3.4.2 CHECKS : 1. The line may be filled up and pressurised through lowest drain line of piping (permanent or

temporary) system.


be released.

3. Vents / drains / local remote impulse lines I integral bypass valves ! radiography plugs at



HYDRAULIC

TEST PROCEDURE

FOR PIPING


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION



3.5 NON-CRITICAL LINES :

Hydraulic testing of non-critical lines may be done to test pressure stipulated in the

respective drawing. The existing valve in the system may be used for isolation. If no

valve is available, then suitable blanking at the end of the system being tested, shall

be welded and hydraulic test carried out with suitable blanks made at site.

4.0 FILLING THE SYSTEM :

a) The system is filled through filling lines connected to the system.

b) Checking of the tilling shall be done through the vents

c) Close the vents after ensuring that all the entrapped air has been vented out.

d) Stop the fill pump and check for any leakage in the system.

e) After ensuring that there are no leaks, prepare for pressurising the piping system. 5.0

PRESSURISING THE SYSTEM :

a) The pressure shall be raised up by means of test pumps.

b) The pressure shall be increased at the rate of not more than 10 Kg / sq.cm. (g) per minute

upto approximately 80 % of the test pressure and by 1 to 2 Kg I sq.cm (g) per minute beyond

that value.

c) Raise the pressure to the hydraulic test pressure. The pressure shall be under proper control

at all times. The pump operator and the responsible person watching the official test gauge must

have radio-telephonic contact. When the test pressure is reached the responsible person

watching the test gauge shall give orders to stop the test pumps immediately and to cut off

electric connections.

d) The test pressure is held for 10 minutes. During the holding time the test gauge pressure

reading shall not drop noticeably.

HYDRAULIC

TEST PROCEDURE

FOR PIPING


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

6.0 HYDRAULIC TESTING :

a) The hydraulic test pressure reading will be taken from the official pressure gauge locatedat

the highest point in the presence of the Boiler Inspector.

b) After the hydraulic test pressure has been noted and agreed to by the inspector, the

hydraulic test pressure is then reduced to not less than the maximum allowable working pressure

and the whole system checks will be carried out.

c) If leaks are found, it will be necessary to release the pressure and drain these portions.

Make the repairs and refill the system as mentioned above and repeat hydraulic test.

d) Details of the leaks noticed during hydraulic test are to be recorded as given below:

1. Exact location of leak(s) component circuit, elevation, materials etc.

2. Description of leak(s) such as straight tube elbow, shop or field weld, torch cut, where a

lug was removed and attachment weld etc.

3. Magnitude of leak weeping / sweating, leaks, burn-through, longitudinal crack 7.0

DEPRESSURISATION OF THE SYSTEM :

a) The system shall be depressurised at a depressurisation rate of 1 Kg. / sq. cm. per

minute.

b) Vents are to be opened once the system pressure reaches 2 Kg./ sq. cm.

c) Drain the piping system fully and release for further work. 8.0 HYDRAULIC

TEST REPORT :

After completion of the hydraulic test, a report shall be prepared in Log sheet L-04 of

QPI for HP Piping and duly signed.

HYDRAULIC

TEST PROCEDURE

FOR PIPING


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

1.0 INTRODUCTION

In a thermal power station or process plant, thermal insulation or heat lagging of piping and

equipment's operating at or above 60 deg. cent. is essential for heat economy and protection of

operating personnel. Any pipe which is at a temperature higher than its sorroundings will loose

heat and the amount of heat lost will depend upon the temperature of the fluid and the thermal

conductivity of the piping material / covering.

The heat lost through bare pipe increases with

a) Increase in the temperature of fluid conveyed

b) Decrease in ambient temperature and

c) Increase in wind velocity of the sorroundings.

The heat so lost has high potential for work and the rapidly increasing cost of fuel in the recent

past has prompted many plant engineers to find all possible means to conserve energy. The

conservation of heat also helps in better environmental conditions for enclosed spaces like T.G.

Hall etc. Providing proper and adequate insulation on to the piping and equipments controls heat

transfer and maintains the required service temp.

2.0 INSULATING MATERIALS The following heat insulating materials are commonly used for power cycle piping and

associated equipments

a) Calcium silicate of density 250 Kg/Cub.M in form of preformed pipe sections to suit

specific pipe sizes / vessel surface configuration.

b) Lightly Bonded Mineral (Rock) Wool Pipe sections of density 144/150 Kg/Cub.M.

c) Lightly Bonded Mineral (Rock) Wool Mattresses of density 150 Kg/Cub.M,

Calcium silicate is generally used when specifically asked for by the customer. This is used as

the first layer of insulation where hot face temperature exceeds 400 deg C and the subsequent

layers are of Lightly Bonded (Rock) Wool mattresses.

THERMAL INSULATION

FPR PIPING &

EQUIPMENTS ERECTION

PROCEDURE


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

If Calcium silicate is not asked for then Lightly Bonded (Rock) Wool Pipe sections/ Lightly

Bonded (Rock) Wool mattresses are used for various layers of insulation as per thickness

requirement.

Finishing cement is applied over the last layer of pipe sections / mattresses on all

piping/equipments if specifically called for. The final insulation covering is carried out with

Aluminium/ Galvanised iron sheets of required gauges.

3.0 THERMAL INSULATION SCHEDULE Thermal insulation schedule for piping and equipments giving piping/equipment details,

insulation thicknesses are always specific to the project. These schedules shall be given

separately to site / erection agency during execution of the project. (See Annexure-1 & II for

sample details)

4.0 METHOD OF APPLICATION

( FOR ROCKWOOL MATTRESSES / ROCKWOOL PIPE SECTIONS ) The method of application is a highly skilled job. Badly fitted/laid insulation can lead to greater

heat loss, higher cold surface temperature than that estimated and frequent maintenance.

Following are important points to be considered during the application of the insulation.

4.1 Before applying insulation, it should be ensured that all instrument tappings, clamps,

lugs and other connections on the surface to be insulated have been properly installed

as per relevant drawings.

4.2 All surfaces to be insulated shall be cleaned of all foreign materials such as dirt, grease,

loose scale, moisture etc.

4.3 Welding of lugs, attachments, clips etc. on the surface to be insulated for supporting

insulation shall not be carried out without the permission of the authorised person.

4.4 AH flanged joints shall be insulated only after final tightening and testing.

4.5 The insulation shall be applied to all surfaces when they are at ambient temperature.

4.6 The indicated thickness of insulation (as indicated in Thermal insulation schedule) are

minimum requirement which should be maintained. Any change in the thickness

THERMAL INSULATION

FPR PIPING &

EQUIPMENTS ERECTION

PROCEDURE


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

of the insulation should be done only after prior approval of the design engineer.

These shall be given during execution stage separately for each project.

4 7 The day-to-day insulation work should be covered with suitable protective materials to

prevent the rain water entry, if same is expected.

4.8 Where more than one layer of insulation is involved, mattresses/ pipe sections should have

staggered joints ( at 60 deg) and they must be held in close contact with face of pipes/fittings by

means of binding wires / Aluminium bands/seals. Circumferential joints of multilayer insulation

should also be staggered. (Refer Drg. No. PE-4-999-169-01 & PE-4-999-169-02).).

4.9 Where mattresses insulation is applied (in one or more layers) wiremesh should face on outer

side.

4.10 Insulation mattresses shall be held in place by fastening over with binding wire. Care

should be taken to see that the flexible insulation mattresses are not unduly compressed. The

ends of binding wire shall be lightly twisted together, bent over and pressed into the insulation.

Spacing between binding wires shall be at intervals of 300mm. (Refer Drg No. PE-4-999-169-

01.)

Similarly if pipe sections are used then aluminium bands/seals shall be used at

spacing of 300 mm. (Refer Drg No. PE-4-999-169-02).

4.11 Where junctions between bodies of different diameters occur and difference in insulation

thickness is specified, the greater thickness is to be continued for a length equal to one diameter

of the smaller body and then smoothly tapered to the required smaller thickness over a length

equal to two diameters of the small body.

4.12 The indicated thickness of insulation (as indicated in section B and C) are minimum

requirement which should be maintained. Any change in the thickness of the insulation should

be done only after prior approval of the design engineer.

4.13 The day-to-day insulation work should be covered with suitable protective materials to

prevent the rain water entry, if same is expected.

4.14 The insulation shall be cut to fit the piping O.D / equipment and shall be wrapped on the

equipment and held in position with proper support and wires. All t

THERMAL INSULATION

FPR PIPING &

EQUIPMENTS ERECTION

PROCEDURE


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

should be properly staggered and tigntly butted and adjacent edges laced together

with lacing wire. (Refer Drg. No. PE-4-999-169-01)

4.15 The insulation of valves and flange joints shall be enclosed in a removable jacketing so

that it may be removed without disturbing the concerned equipment or piping. The thickness of

insulation shall be same as that of the pipe line in which these valves and fittings are located.

(Refer Drg. No. PE-4-999-169-06 & PE-4-999-169-07.)

4.16 Steam/Air /Gas leakages in and around the pipes to be insulated shall be attended before

applying insulation.

4.17 In order to provide support to Aluminium cladding support rings made out of 20 x 3 mm

M.S. flats shall be fixed at equal intervals of approximately 850 mm spacing and at every

circumferential joints. These rings shall be fixed with 'L type lugs. and shall be fabricated from

20 x 3 mm M.S. flats. To reduce heat conductivity through these lugs 20 mm x 3 mm size

asbestos / ceramic mill board shall be used between rings and lugs (Refer Drg No. PE-4-999-

169-04 & PE-4-999-169-13).

4.18 Spacing between supporting rings for vertical piping shall be 3 mtrs. Support rings are to

be provided only when the vertical height exceeds 3 mtrs. (Refer Drg No. PE-4-999-169-04 and

PE-4-999-169-05).

4.19 For vertical pipes since support ring is provided at every 3 mtrs. interval, only two spacer

rings shall be provided in between support rings.

4.20 Insulation support shall have one coat of bitiminous paint.

4.21 Pipe hangers and supports should be covered in such a way that the moisture can not

penetrate into the insulation.

4.22 It is very important that sheet metal cladding should be done by a well experienced and

competent fabricator. Person doing the job can alter the method of fixing of cladding sheet only

after consulting the concerned design engineer.

4.23 The longitudinal joint in the outer cladding sheet should always be at the lower half of the

circumference for horizontal piping so that no rain water enters the insulation through the joints.

(Refer Drg No. PE-4-999-169-01 & PE-4-999-169-02)

THERMAL INSULATION

FPR PIPING &

EQUIPMENTS ERECTION

PROCEDURE


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

4.24 The joints of outer cladding should be staggered axially.

4.25 Inside surface of Aluminium sheet shall be coated with one coat of Bituminious paint.

4.26 The cladding sheet shall be provided directly over the insulation or over finishing

cement (IF APPLICABLE). Suitable flashing and weather proofing shall be provided at all

nozzles, manholes and other projections to prevent the entrance of water.

4.27 Loose wool can be taken from wool mattresses, wherever required.

4.28 Sealing compound to be applied on all cladding sheet joints.

4.29 Aluminium sheet covering on outdoor horizontal pipes shall be provided with 3 mm drain

hole at bottom centre line at 6 mtr intervals.

4.30 Equipment's name plates shall not be insulated.

4.31 Clips made out of sheet shall be riveted inside the box for insulation of valves and flanges

to hold the insulation in box. (Refer Drg. No. PE-4-999-169-06.).)

4.32 The insulation local to the inspection points of the critical piping shall be removable. LIST

OF DRAWINGS FOR ROCKWOOL PIPE SECTIONS / MATTRESSES

S. DESCRIPTION DRAWING No.

No.

a) Insulation application (For horizontal pipes with mattresses) PE-4-999-169-01

b) Insulation application (For horizontal pipes with pipe sections) PE-4-999-169-02

c) Insulation application (For vertical pipes with pipe sections/ PE-4-999-169-03

mattresses)

d) Insulation application (Cladding sheet support ring for PE-4-999-169-04 horizontal

pipe O.D. >114.3 mm and horizontal equipments).

e) Insulation application (Insulation support ring for vertical PE-4-999-169-05 piping

and vertical equipments)

f) Insulation application ( Valves) PE-4-999-169-06

THERMAL INSULATION

FPR PIPING &

EQUIPMENTS ERECTION

PROCEDURE


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

g) Insulation application (Tees & Flanged joints) PE-4-999-169-07 h)

Insulation application (Elbows & Bends) PE-4-999-169-08 i) Insulation

application (Equipment) PE-4-999-169-09

j) Insulation application (Fabricated heat insulating cover for PE-4-999-169-10 Man-

hole)

k) Insulation application (Metal flashing on hanger rod protrusion) PE-4-999-169-11 I)

Insulation application (Details of 'P', 'Q', & 'R') PE-4-999-169-12 m)

Insulation application (Support ring for pipe) PE-4-999-169-13

5.0 METHODS OF APPLICATION

(FOR CALCIUM SILICATE PERFORMED RIGID PIPE COVERING)

5.1 STORAGE Calcium silicate preformed pipe Coverings should be kept dry during storage and at

erection site.

5.2 SURFACE PREPARATION a). All Pipelines & Equipment surfaces should be dry, free from dust, rust, grease and scale

before application.

b) All hangers, brackets and pipe clamps etc. should be in position.

c) All surfaces should be brush-coated with a suitable anti-corrosive primer wherever

necessary before they are insulated.

d) Necessary pressure-test for the pipes to be carried out before insulation.

e) An the joints to be tightened so that there is no leakage.

5.3 MECHANICAL SECUREMENT OF PIPE COVERINGS. a) For securing insulation on horizontal pipes, circumferential bands of Aluminium are

used in addition to G.I. binding wires. The spacing between binding wires shall be

300 mm and between Aluminium bands shall be 450 mm.

THERMAL INSULATION

FPR PIPING &

EQUIPMENTS ERECTION

PROCEDURE


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

b) For securing insulation on vertical pipes, support rings fabricated from M.S.

flats, cleats etc. are used which provide support for insulation and prevents its

downward displacement. ( Refer Drg No. PE-4-999-169-05)

5.4 INSULATION OF PIPES

a) To use Half Round pipe coverings upto N.B. 200 mm (8")

b) To use Curved Segments for pipes N.B. 225mm (9") to 610mm (24") dia.

c) To use Bevelled Lags (Side-arch type) for above 610mm (24") dia. pipes and cylindrical

surfaces.

d) All unavoidable gaps in the circumferential or longitudinal joints should be filled with

Calcium Silicate Plastic Composition

e) For single layer of insulation, circumferential joints should be staggered.

f)) In case of half round pipe coverings, one half of the starting pair should be cut to half

length. Subsequently full length pieces should be fitted, that will stagger the circumferential

joints. The longitudinal joint will come in a line. (Refer Drg No. PE-Fig1)

g) In case of curved segments and bevelled lags alternate segment of half length and full

length to be used in the starting set. Now use of full length segments subsequently, will stagger

the circumferential joint. (Refer Drg No. PE-DG-999-169-M001 Fig 1)

h) For multilayers of insulation, circumferential as well as longitudinal joints should be

staggered from 1st layer joints. ( Refer Drg No. PE-4-999-169-M001 Fig 1)

i) Staggering the second layer of circumferential joints from 1st layer

circumferential joints can be achieved by varying the second layer length from 1st

layer lengths of pipe coverings.

j) For securing insulation to pipe, use binding wire of 1 .Omm to 1.5mm dia. or metal band

of 20mm width and 1 mm thick. The choice of material and corrosion protection for

metal bands, wires depend on environmental conditions.

k) Each section of insulation should be held in place by atleast two nos. circumferential

bands or wires.

THERMAL INSULATION

FPR PIPING &

EQUIPMENTS ERECTION

PROCEDURE


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

I) The spacing between the bands should not be more than 450mm.

m) At each end of pipe coverings, the distance between the end of pipe covering and the

band/wire should not be less than 50mm.

n) The wire should be tightened by twisting and the ends of wire to be pressed on to the

insulating material.

5.5 INSULATION OF FITTINGS

a) Insulation of valves and bends etc. should be done using performed pipe coverings as far as

practicable ( Refer Drg No. PE-4-999-169-M001 Fig 3, 4)

b) Thickness of the pipe covering near flanges should be such that it clears the flange O.D.

Now pipe covering can be provided on flanges as shown in ( Refer Drg No. PE-DG-999-169-

M001 Fig 2)

c) Sufficient space should be provided to enable withdrawal of flange bolts while working on

pipeline with minimum disturbance of insulation.

d) Space provided for bolts withdrawal should be filled with Calcium Silicate Plaster

Composition.

e) Similarly the valve can be insulated as shown in ( Refer Drg No. PE-DG-999-169-M002

Fig 3). However the gland section should be kept exposed for routing maintenance.

f) For bends, pipe coverings to be cut as per the bend radius and to be fitted on the bend as

shown in ( Refer Drg No. PE-DG-999-169-M002 Fig 4). Any unavoidable gaps should be filled

with Calcium silicate Powder.

5.6 EXPANSION JOINTS

a) Due to difference in expansion coefficients of metal and insulating material, it is necessary to

make allowance for differential movement between hot surface insulation.

b) Expansion joints should be provided at the spacing as per following:

Temperature Deg cent Spacing Interval (m)

Upto 200 5 200-300

THERMAL INSULATION

FPR PIPING &

EQUIPMENTS ERECTION

PROCEDURE


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

300-400 2.7 Above 400 2

c) At the expansion joint sufficient gap should be provided. The gap should be figthly packed with

fibrous insulation which in turn to be covered with performed section just as in case of flanges.

LIST OF DRAWINGS FOR CALCIUM SILICATE PIPE SECTIONS S.No.

DESCRIPTION DRAWING No.

a) Insulation application (For Pipe and Flange insulation) PE-DG-999-169-M001

b) Insulation application (For valves and Bends insulation) PE-DG-999-169-M002

6.0 METHOD OF APPLICATION OF CALCIUM SILICATE

POWERED (ASBESTOS FREE - PLASTIC COMPOSITION )

Calcium Silicate Plastic Composition is to be applied by Hand trowelled method which is given

below. Slurry of calcium silicate is formed by mixing calcium silicate powder with requisite

water (i.e. 1.8 times by weight of Dry Powder) and suitable binders such as Sodium Silicate to

make consistent workable mixture. The commercial grade/Refractory grade binder i.e. Sodium

Silicate is mixed in the ratio of 5 to 6 percent by weight of powder. (Sodium Silicate should be

mixed after adding water in the powder). The mortar thus formed by above method is to be

applied for filling of gaps/joints between the block/pipe coverings during installation by hand

trowelling.

The above Powder mixture can also be used for Insulation of irregular surfaces like in Turbine

casing & Boiler. For Boiler/Turbine application, we recommend using powder by

Trowelling/Gunniting. by providing Chicken Wire Mesh reinforcement after every 25mm

thickness. The subsequent layers of Insulation to be built-up after 1st Layer is completely dried.

Surface should be properly prepared for application, by cleaning the surface with cloth & wire

brush to make it free from oil/grease etc. If possible, Y-shaped anchors may be provided on the

equipment before application of Powder on it.

THERMAL INSULATION

FPR PIPING &

EQUIPMENTS ERECTION

PROCEDURE


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

THERMAL INSULATION

FPR PIPING &

EQUIPMENTS ERECTION

PROCEDURE


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

ANNEXURES-1

THERMAL INSULATION SCHEDULE FOR PIPING

Project Title Date :

Project Stage SPEC NO.

Design Parameters

Cold Face Temperature in Deg. C

Esmissivity (Dimensionless)

Wind Velocity in M/Sec.

Materials

Insulation Material

Material Density in Kg/Cub.M.

Cladding Material

Cladding Material Gauge

Thermal Conductivity vs. Mean

Temperature Equation

Design Heat Loss in W/Sq.M. at Cladding Surface

THERMAL INSULATION

FPR PIPING &

EQUIPMENTS ERECTION

PROCEDURE


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

ANNEXURE-11

FOR PIPING

S.NO.

DESCR.

HF

PIPEOD

PIPE

BENDS

BENDS

REDUCERS

ELBOWS

TEES

FLANGES

VALVES

INSUL

TEMP

LENGTH

<=45

>45

THICK

(DEG C)

(MM)

(MTRS)

(No.)

(No.)

(No.)

(No.)

(No.)

(No.)

(No.)

(MM)

FOR EQUIPMENTS

S.NO.

DESCRIPTION

EQUIPTS

NO. OF (DEG.

C)

HF-TEMP. (MM)

EQUIP. O.D.

(MM)

INSUL. THICK

THERMAL INSULATION

FPR PIPING &

EQUIPMENTS ERECTION

PROCEDURE


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

WELDING, NDE & PWHT


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

WELDING

Welding operation at site on Piping shall be controlled in the following 3 ways

WELDING OPERATION

A) INPUT CONTROL B) PROCESS CONTROL C) TESTING

A) INPUT CONTROL : The following Inputs shall be ensured prior to start of welding.

INPUT CONTROL

1) Qualified Welders 2) Work Instructions 3) Welding consumables

QUALIFIED WELDERS :

Welders shall be qualified for Pipe Welding at Site as per the welders test procedure.

Adequate Qualified welders shall be ensured for TIG & ARC Welding of Carbon &

Alloy Steel materials.

Validity of IBR certificates shall be ensured for the Welders to be engaged in IBR

welding.

The Records of Welder Performance Qualification Test shall be maintained and

Qualified welders shall be issued with Identity card for verification and review by the

Authorised Inspection Agency.

1)

Q

Q

a

0

WELDING

NDE & PWHT


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

Q Welder-wise Record on Welders daily performance shall be maintained to monitor and

evaluate the Welders performance at regular intervals.

2) WORK INSTRUCTIONS :

Q Erection Welding Schedule (EWS) shall be supplied by Units for reference on welding

details at site.

WELDING

NDE & PWHT


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

Q Welding Procedure Specification (WPS) shall be supplied by Units to the respective

Regional Head Quarters and the same shall be qualified at site if required..

Q Welding Manual prepared by respective Regional Head Quarters shall be made available for

reference at site.

»

Q Erection Manual prepared by respective Regional Head Quarters shall be made available

for reference at site.

Q Erection Drawings supplied by manufacturing units shall be referred for any specific

instructions to be followed at site.

Q Indian Boiler Regulations shall be referred for the boilers to be erected in India. 3)

WELDING CONSUMABLES :

Q Ensure the procurement of Welding Electrodes / Filler wires at site from the Approved

Vendors recommended by the Manufacturing Units.

Q Receipt / Storage / Issue of welding consumables shall be done as per the recommended

procedure given in welding manual.

Q Drying of electrodes and maintaining the temperature in holding and portable ovens shall

be ensured as per the parameters given in annexure.

Q Selection of welding electrode / filler wire shall be based on the details given in Erection

Welding Schedule / Erection Drawings supplied by the Manufacturing Units and

Welding Manual may be referred where the details not specified in the documents

given by Units.

B) PROCESS CONTROL : The following checks shall be carried out prior to start of

welding and during welding process.

PROCESS CONTROL

1. GENERAL CHECKS 2. WELDING PROCESS CONTROL

WELDING

NDE & PWHT


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

1) GENERAL CHECKS :

0 Availability of Equipment / Accessories and welding consumables shall be assessed

before start of welding.

Q Clearance for welding shall be obtained from Erection in-charge and confirm the

material of the Pipes to be welded, Root gap & Matching of ID between the two pipes

are within permissible tolerance prior to start of welding.

Q Proper temporary supports and locking of Pipes to be welded shall be ensured to avoid and

possible distortion during welding.

Q Weld Joints shall be identified with suitable numbering in sequencial order for easy

Identification of the weld joint.

2) WELDING PROCESS CONTROL : Q Required Preheat temperature as given in EWS / WPS / HT Manual shall be ensured and the

same to be maintained during welding.

Q Selection of correct welding electrodes / filler wires shall be ensured prior to start of

welding.

Q Drying of electrodes and maintaining the temperature in holding and portable oves shall be

ensured prior to issue / use.

Q Welding parameters like current, speed, gas flow, weave width etc., shall be ensured during

welding.

Q Weld reinforcements shall be maintained as per recommended permissible limit. Q

Dressing of weld joints shall be ensured for Visual Inspection and NDE checks. C) TESTING

: Weld Joints shall be Inspected by the following Testing. TESTING

1) VISUAL INSPECTION 2. NON DESTRUCTURE EXAMINATION


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

1. VISUAL INSPECTION :

Q After completion of welding, visual Inspection shall be done to ensure the weld joints

are free from any surface defects like pin holes, cracks, incomplete fusion, under cuts

etc.

Q If any defects noticed on the weld surface, the same shall be repaired as per the

recommended weld Repair procedure.

2. NON - DESTRUCTURE EXAMINATION : Q Non Destructive Examination (NDE) shall be performed on the Weld Joints welded at

site as per the requirements to ensure the soundness of the welds.

Q The major NDE methods being followed at site are Lliquid penetrant examination (PT),

Magnetical particle examination (MT), Radiographic examination (RT) and

Ultrasonic examination (UT).

Q The extend of NDE shall be performed are specified in the EWS / NDE manual / Drawings.

Q NDE shall be performed using Qualfied procedures and personnel only.

Q Acceptance norms shall be based on the relevant code of construction and built into the

respective NDE procedures given in the NDE Manual.

Q NDE records shall be maintained correlating the weld joint for the Test details.


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

POST WELD HEAT TREATMENT Q Post Weld Heat Treatment (PWHT) shall be performed by locally heating a circumferencial

band including the entire weld and adjacent area of base metal by

induction or electrical resistance heating.

»

Q PWHT requirement and parameters are specified in EWS / WPS if available or otherwis

refer Heat Treatment Manual for guidance and selection of parameters.

Q Calibration of Temperature Recorder shall be ensured and records shall be maintained to

ensure its validity and periodicity of calibration of the equipment as per the calibration

procedure.

0 Availability of materials like heating coils, thermocouples, control panel, temperature recorder,

insulation materials etc., shall be ensured prior to start of PWHT operation.

Q Prior to start of PWHT operation, a Job Card shall be prepared including details of weld

reference, soaking time, soaking temperature, rate of heating and cooling, temperature recorder

details as per sample format given in Heat Treatment Manual.

Q Heating arrangements and thermocouple position shall be witnessed prior to closingwith

pad/insulation materials.

Q On completion of PWHT operation, the actual chart shall be verified to ensure the

parameters and the same may be recorded in the job card.

Q If any interuption during PWHT operation or any abnormalities noticed in the actual

chart, Heat Treatment Manual shall be refered for corrective action.

Q Records like Job card and PWHT Charts shall be maintained for future reference.


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

COLOUR CODE CHART FOR TUBES & PIPES Following are the revised colour codes which are applicable for Triuchy Complex supplied

Tubes & Pipes to identify the material specification.

SPECIFICATION

COLOUR 1

COLOUR 2

COLOUR 3

12 X 1 MF

RED

YELLOW

13 CR MO 44

ALUMINIUM

BLACK

A 200 GR. T5

ALUMINIUM

RED

YELLOW

A 200 GR. T9

ALUMINIUM

GREEN

YELLOW

AISI 602

WHITE

YELLOW

API 5LGr.B

ALUMINIUM

BS 3059 PART2 CDS/HFS 360

ALUMINIUM

BLACK

BROWN

BS 3602 PART1 CDS 360

ALUMINIUM

BLACK

BLUE

NFA49-213 42C ALUMINIUM BLUE BROWN

NFA49-213TU 10CD9.10

ALUMINIUM

BLUE

RED

NFA49-213TU 15CD2.05

ALUMINIUM

BLUE

GREEN

NFA49-213TU Z10CD9

ALUMINIUM

BLUE

YELLOW

NFA49-213 TU Z10CDVNB09.01

ALUMINIUM

GREEN

RED

SA 106 Gr. B

RED

SA 106 Gr. C

BLUE

SA 179

BLACK

BLUE

GREEN

SA 192

WHITE

SA 199 T5

BLUE

BROWN

RED

SA 209 Gr. T1

ALUMINIUM

RED

SA 210 Gr. A1 YELLOW SA 210 Gr. C

BLUE

GREEN

SA 213Gr.T11

ALUMINIUM

YELLOW

SA 213 Gr.T12

BROWN

YELLOW

SA 213 Gr.T2

BROWN

GREEN

SA 213Gr.T22

GREEN

RED

SA213Gr.T5

BLACK

BROWN

GREEN

SA 213 Gr.T9

BROWN

WHITE

SA 213 Gr.T91

GREEN

YELLOW

SA213 Gr.TP 304

BLUE

GREEN

YELLOW

SA 213 Gr.TP 304H

BLACK

BLUE

YELLOW

SA 213 Gr.TP 304L

BLUE

WHITE

YELLOW

SA 213 Gr.TP 309H

BLACK

BROWN

YELLOW

SA 213 Gr.TP 316

BROWN

SA 213 Gr.TP 316 Ti

BLACK

BLUE


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

SPECIFICATION

COLOUR 1

COLOUR 2

COLOUR 3

SA213 Gr.TP 316L

BLUE

BROWN

YELLOW

SA213 Gr.TP 321

BLUE

WHITE

SA213 Gr.TP 321 H

BLACK

WHITE

SA213 Gr.TP 347H

BLACK

YELLOW

SA 268 Gr. TP 405

ALUMINIUM

GREEN

SA 268 Gr.TP 410

BROWN

RED

YELLOW

SA 268 Gr. TP 443

BLUE

GREEN

WHITE

SA269TP316

GREEN

RED

YELLOW

SA312 Gr.TP 316L

BLACK

BLUE

BROWN

SA312 Gr.TP 321

BLUE

BROWN

SA 312 Gr.TP347

BLUE

RED

WHITE

SA 333 Gr. 1

BLACK

BROWN

RED

SA 333 Gr. 3

BLACK

GREEN

RED

SA 333 Gr. 6

BLUE

GREEN

RED

SA 333 Gr. 1

BROWN

GREEN

RED

SA 333 Gr. 3

BLACK

RED

YELLOW

SA 334 Gr. 6

BLACK

BLUE

RED

SA 335 Gr. P1

BROWN

GREEN

YELLOW

SA335 Gr. P11

GREEN

WHITE

SA 335 Gr. P12

BLACK

RED

SA 335 Gr. P2

BLUE

BROWN

GREEN

SA 335 Gr. P22

BLUE

RED

SA 335 Gr. P5

BLACK

BROWN

SA 335 Gr. P9

ALUMINIUM

BROWN

SA 335 Gr. P91

BROWN

RED

SB 163 Inconel

BLACK

GREEN

YELLOW

ST 35.4

ALUMINIUM

BLUE

Steel 20

GREEN

Structural Tubes & Pipes

BLUE

BROWN

WHITE

X20 Cr. Mo V 121

BLACK


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

RECORD OF WELDER PERFORMANCE

QUALIFICATION TEST

Performance Test No.

Date :

Welder Code :

Material Groupings permitted :

Thickness Qualified : (This performance test is as per Procedure No. )

TEST MATERIAL

Specification :

Thickness (and Dia of pipe) :

Shielding Gas(es)

(sketch)

Welder's Signature

Agency Conducting Test We certify that the statement in this record are correct and that the test weld were prepared, welded and tested in accordance with requirements.

This is valid upto

Welding In-charge/BHEL

Site :

Welder's Name & Address

Welding Process :

Position(s) Qualified

Dia Qualified :

Filler Material :

SFA No.:

AWS Classification :

Position of test weld Pre-heat temp : Test Joints

PROCESS VARIABLES

Current :

Inter Pass Temp :

Test Results

Type Bend

Type Bend

Type Bend

Type Bend

Radiography Ref. & Results :

Polarity :

Post-Heat Temp

Results Results Results Results


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

(a) Maximum permissible out-of-alignment at bore

Bore (mm)

Max. Misalignment For GTAW

(mm) For SMAW

Upto 100 Over 100 to 300 Over

300 '

1.0 1.6 1.6

1.0 1.6 2.4

Maximum Permissible Reinforcements

Thickness of base metal

For Service above 400° C

Temperature upto & inci 400°C

Upto 3.0

2.0

2.5

Over 3 - 5

2.0

3.0

Over 5-13

2.0

4.0

Over 13-25

2.5

5.0

Over 25 - 50

3.0

6.0

Over 50

4.0

All dimensions in mm.


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

Drying and Holding Parameters for Welding Electrodes

AWS Classification (*)

Baking Temperature °C Time (Hours)

Holding Temperature °C (@)

E7018

250-300 2

100 min

E 7018-1

250-300 2

100 min

E 7018-A1

250-300 2

100 min

E 8018-B2

250-300 2

100 min

E 8018-B3

250-300 2

100 min

E 8018-B2L

250-300 2

100 min

E 9018-B3L

250-300 2

100 min

E 309 & E347

250-300 1

100 min

Note : (*) For other electrodes, supplier's recommendations shall be followed. (@) Maintain the temperature in the oven till issue.

POWER CYCLE PIPING

ERECTION

FILLER WIRE, SMAW ELECTRODE FOR BUTT WELDS IN TUBES AND PIPES

Material

Welding Process

P1Gr1 P1Gi2

P3Gr1

P4Gr1

P5AGr1

P5BGi2

P8

CrMoV

P1Gr1

GW

RT1/2MO

P1Gn2

SMWV

E7018-1

Motel

P3Gr1

GW

RT1/2MO

RT1/2MO

SMWV

E7D18-1

E7018A1

P4Gr1

GTWV

RT1/2MO

RT1/2MO

RT1Cr1/2Mo

SMWV

E7D18-1

E7018A1

E801&B2

P5AGr1

GW

RT1/2MO

RT1/2MO

RT1Cr1/2Mo

RT21/4Cr1Mo

RT21/4

SMflW

E7018-1

E7018A1

E8018e2

E901863

Cr1Mo

E9018-

•

B3

PSBGr

GT?W

TGS9

2

Ob

PSBGr

GTOV

TGS9

2

SMWV

Cb

re

G1?W

ERNQ3

ERNiQ3

RT347

SMAW

ENiCri=e3

ENOFe3

Off

QMoV

G1WV

RT21/4Cr1Mo

RT21/4Cr

Note2

SMWV

E901&63

1M3

E9018B3

Note -1: E7018-A1 for P1 Gr2 + P1 Gr2 when PWHT is involved. Note-2 : DIN14MoV63

equivalent

POWER CYCLE PIPING

ERECTION

BHEL VALVES

POWER CYCLE PIPING

ERECTION

GUIDELINES FOR BHEL VALVES INSTALLATION

Q Availability of the following documents shall be ensured for details on receipt, storage, and

Installation Instructions.

Packing slip / Shiping List.

BHEL Valves storage & installation Manual

Product checklist for Valves.

Valve/Actautor schedule, Erection Drawing etc.,

Q On receipt of the items, the box shall be opened and the valves to be identified by ensuring its

DU and Tag numbers.

0 On receipt of the valves, Inspection shall be carried out to ensure the valves to be identified by

ensuring its DU and Tag numbers.

Q Storage of the valve shall be ensured as per the recommended procedure given in BHEL

Valves storage Instruction Manual / Product Checklist / Storage Manual etc.

Q The correct Valves shall be identified by checking the following prior to start of Installation of

Valves in Pipelines.

DU number

Tag nubmer

Length & Nominal bore

Valve Grade

Direction of flow etc.,

D Cleaning of Valves shall be done using compressed air prior to start of Installation.

Q Access for Operation / Maintenance of the Valves shall be ensured at the time of

Installation.

Q Location of valve shall be ensured so that this will not foul with other pipes, platforms etc.

POWER CYCLE PIPING

ERECTION

Q If any modification is required for ease of operation / maintenance, shall be done with

consultation of Designer.

Q Direction of flow shall be ensured while Installation of the valve with pipelines.

Q Protection to Valve seats / Disc shall be ensured by keeping the valve in open position

during welding of weld type valves and in closed position during installation of flange

type vlaves.

Q Adequate support and locking of valves shall be ensured to avoid any possible distortion at the

time of welding.

Q The following checks shall be carried out prior to Installation of Motor operated valves.

Correct size and configuration. Oil

level in gear box.

Q Care shall be taken during Installation of motor operated valves to avoid any possible damage

to Actuators.

Q On completion of Installation of valves, welding shall be ensured as per the requirements for

weld type valves and tightening of flanges as per the Installation instruction for flange

type valves.

Q Tag numbers for valves of less than 2" sizes shall be ensured by fixing it at site after

installation of the valves as per drawing.

POWER CYCLE PIPING

ERECTION

REGENERATIVE SYSTEM

CHEMICAL CLEANING

POWER CYCLE PIPING

ERECTION

completed upto isolating root valves before connecting the flushing. However they are to be

blanked during flushing.

2.10 Ensure that no cutting / welding work is carried out on any equipment after the flushing is

completed.

2.11 Deaerator and Hotwell should be hand cleaned to the extent possible.

2.12 Remove all the orifices/flow nozzles and control valves in the system before flushing and

remove NRV internals where ever applicable.

2.13 Before flushing isolate all the instruments in the system which will be subject to flushing

except those required during flushing.

2.14 Ensure that permanent support are provided for all the pipelines before starting the flushing.

2.15 The flushing has to be done as per the schemes attached herewith.

2.16 The size of temporary pipe lines should be preferably of the same size as used in permanent

system.

3.0 PROCEDURE :

3.1 The flushing of Regenerative system shall be carried out in three stages.

3.2 Line up stage under flushing.

3.3 The total system shall be filled with DM water by running flushing pumps and establish

circulation.

3.4 The DM water circulation shall be carried out in all the sub loops as detailed in section 4, 5, &

6 for one hour each to carry out Mass Flushing.

3.5 Stop the pumps and drain the system.

3.6 The total system shall be filled with DM water and circulation established by running the

pumps.

3.7 Add suitable detergent in mixing tank to a connnection given in the specific write up of

project.

POWER CYCLE PIPING

ERECTION

3.8 The solution shall be circulated in each of the loops, as per section 4,5, & 6 for a minimum

duration of four hours. During circulation, make up shall be made as per the system requirement.

3.9 On complection of flushing of all the loops, continuous make up and drain shall be carried out

in all the loops one by one for a duration of 15 minutes each.

3.10 Drain the system completely and again fill it with DM water.

3.11 DM water shall be circulated in each loop for half an hour once again.

3.12 Drain the system completely.

3.13 Rinse the system with DM water by continuous filling and draining while keeping

the pumps running till effluent is clean and conductivity of drained water shall be less as

per completion criteria.

3.14 Stop the pump and drain the whole system.

3.15 Procedure prepared for specific project to be followed.

4.0 CLEANING OF THE SYSTEM ARE CARRIED OUT IN THREE STAGES.

TYPICAL SCHEME AND CIRCUITRY OF 500 MW M/C ARE GIVEN FOR

INFORMATION.

4.1 Stage - I (Feed Line) of Regenerating System

4.1.1 Make temporary connections as per the scheme. The suction and discharge flanges of BFPs

are to be blanked/bypassed. The circuitry for flushing shall be as follows.

4.1.2 Mixing tank-circulation pumps - BFP suction lines (one line at a time) - Booster Pump suction

line-Feed Storage Tank - Recirculation lines - discharge line of BFP - Bypass of HP heaters 5A &

5B and HP heater 6A & 6B feed control station to mixing tank from a point near economiser inlet

valve.

4.1.3 Mixing tank Ciruculation pumps - BFP suction lines (one line at a time) - Booster Pump

suction line - Feed Storage Tank - Recirculation lines - discharge line of BFP - Through coils of HP

heaters - feed control station to mixing tank from a point near economiser inlet valve.

POWER CYCLE PIPING

ERECTION

4.1.4 Mixing tank - Circulation pumps - S.H. Spray & R.H. Spray lines - to return line to mixing

tank from feed control station.

4.1.5 Carry out flushing as described in procedure section 3.0. 4.2 Stage

II (Condensate lines) of Regnerative System

4.2.1 Make temporary connections as per the scheme. Size of temporary pipe lines should be

preferably -of the same size as used in normal operation. The circuitry for flushing shall be as

follows.

4.2.2 a) Mixing Tank - Circulation pumps - condensate discharge line - Gland steam condenser by

pass - CPU bypass - drain cooler & LP heater 1 bypass -LPH 2 bypass - LPH 3 bypass upto a point

before deaerator - Mixing Tank.

b) Mixing Tank - Circulation pumps - Condensate discharge line - then through gland

steam condenser - CPU bypass - Drain cooler - LPH 1 - LPH 2 -LPH 3 - upto

Deaerator and to return to mixing tank.

4.2.3 Carry out flushing as described in procedure section 3.0 4.3 State -

III (Drip lines) of Regenerative System :

4.3.1 Make temporary connections as per the. The circuitry for flushing shall be as follows .

4.3.2 HP Heater Drip Lines :

a) Mixiing Tank-circulation Pumps - HPH 6A alternate drip line to HP flash tank -HPH 6A

shell - HPH 5A shell - HPH 5A drip line to Deaerator - Finally to Mixing Tank.

b) Mixing Tank-circulation Pumps - HPH 6B alternate drip line to HP flash tank -HPH 6B

shell-HPH 5B shell-HPH 5B drip line to Deaerator-Finally to Mixing Tank.

c) Mixing tank - circulation pumps - HPH 5A alternative drip line to HP flash tank -HPH 5A

drip line to deaerator - Finally to mixing tank.

d) Mixing tank - circulation pumps - HPH 5A alternative drip line to HP flash tank -HPH 5A

drip line to deaerator - Finally to mixing tank.

POWER CYCLE PIPING

ERECTION

4.3.3 LP Heater Drip Lines

a) Mixing Tank-circulation Pump-Alternate drain line from LPH 3 to LP flash tank -LPH 3 shell -

Temporary line between LPH 3 & 2 - LPH 2 shell - Alternate drain from LPH 2 LPFT - Mixing

Tank.

b) Mixing Tank - circulation Pump - Alternate drain line from LPH 3 to LPFT - Drip from LPH 3

to LPH 2 - LPH 2 shell-Drip from LPH 2 to LPH 1 - Drip line from LPH 1 to drain Cooler - Drip

line from the cooler to LP flash tank then finally to mixing tank.

4.3.4 Carry out flushing as described in procedure section 3.0.

5.0 POST FLUSHING OPERATION :

5.1 A. Following temporary lines are to be removed :-

a. All temporary lines of the loop.

b. Temporary line from the system to Mixing Tank.

c. Temporary line from Alkaline Pump discharge to system.

5.2 Blanks provided in the system are to be removed.

5.3 Stubs used for Alkali Flushing are to be normalised.

5.4 Any choked drain line, as identified during flushing operation, should be attended either by

opening the valve bonnet or by cutting the line.

5.5 After draining the Deaerator, it should be thoroughly inspected from inside and cleaned

properly (The Deaerator manhole doors should be kept open for 8-10 hours prior to entry for

expelling chemical gases).

5.6 Install the can not valves, flow nozzles, orifices in the system permanently after taking due

care so that no foreign matter enters the system agin.

5.7 In case of BFP suction flow nozzles after its welding it is always advisable to flush the line

again before entering water to the pump. Suction pipe at BFP flange may be lifted slightly and some

sheet may be kept at pump flange for this purpose.

POWER CYCLE PIPING

ERECTION

POWER CYCLE PIPING

ERECTION

CHEMICAL DOSING AND

STEAM BLOWING

POWER CYCLE PIPING

ERECTION

INTRODUCTION

The natural water contains solid, liquid and gaseous impurities and therefore cannot be

used for the generation of steam in boiler. The necessity for reducing the corrosive nature and

quantity of dissolved and suspended solids in feed water has become important. The quality of

feed water is continuously monitored. The feed water and steam samples drawn from various

parts of the boiler system are analysed and accordingly chemicals like phosphates and hydrazines

are added. The phosphates are dosed at drum. The hydrazine and amonia is dosed at feed water

before entry into boiler feed pump.

Internal Chemical Dosing Sytem :

The boiler chemical dosing system contains the following

a) Chemical mixing and metering tanks

b) Chemical dosing pumping units

c) Piping

Chemical Mixing and Metering Tanks : In the chemical mixing and metering tanks the chemical are mixed with addition of D.M. Water and

agitated well by agitators. The inner face of the tanks are lined with rubber to avoid contamination.

The tanks are fitted with direct level indicators and level switches for monitoring the level. An

overflow line is located at bottom of the tank. For adding chemicals, opening is provided at the top

of the tank with strainer to prevent choking of suction pipes and pumps by the lumps.

Stainless steel agitator vanes fitted to SS Shaft is driven by a electrical motor is used for mixing the

chemical in the tank.

Chemical dosing pumps :

Mostly reciprocating pumps are used in this system. The pump drive mechanism transmits a

reciprocating action with a provision to change speed to a plunger operating in a cylinder. This

piston's forward movement pumps out the liquid through the outlet check value. The backward

movement of the piston allows fresh liquid to enter from metering tank through the inlet port and

check value.

POWER CYCLE PIPING

ERECTION

By external handle, the stroke length of piston can be altered and thus altering the liquid flow

outputs, as per the requirement of dosing.

Piping : The piping system for chemical dosing consists of (a) DM water supply lines to dosing tanks (b)

Tank overflow and drains (c) Pump suction (d) Discharge lines to dosing points etc.

Condensate discharge piping from CEP and feed pump suction lines are the points where hydrazine

is dosed phosphate is dosed directly in the boiler drum.

The phosphate dosing system is called high pressure (HP) dosing and the hydrazine dosing system

is called low pressure (LP) dosing system.

Erection : The mixing and metering tanks for H.P. and LP. dosing systems shall be erected on their

foundations, as per layout drawings. Orientation of tank, elevation and distance with respect to

columns and pumping units shall be checked.

After completion of alignment these tank foundation bolts shall be grouted.

The pumping units shall be erected over their respective foundations as per layout drawings.

Elevator, distances and orientation of base frames and pumps shall be checked with respect to

drawings.

The alignment of couplings between motor and pump shall be checked. Necessary packer plates or

shims shall be used for aligment. All the alignment readings shall be recorded.

The erection of pipings shall be done as per the scheme. Location of valves, vents, instrument

tapping etc. shall be convent for operation and maintenance. The pump suction discharge valve

manifolds, the tank drains and overflow lines, safety relief valve discharge lines shall be layed at

ground level, neatly in and well supported. The DM Water supply lines to tanks and pump

discharge lines after valve manifolds shall be routed at an higher elevation and supported.

POWER CYCLE PIPING

ERECTION

1.0 STEAM BLOWING :

1.1 General The purpose of steam blowing is to remove scales loose material, iron cutting etc. that might have

been entraped in super heaters, reheaters and related piping during manufacture, storage and

erection at site. Failure to remove the debris may result in damage to the turbine blades, valves etc.

1.2 Basic Technique :

The steam blowing is carried out by puffing method. This technique will give a thermal shock to the

contour being purged to dislodge the scale etc. which will be subsequently cleared by the expanding

steam.

1.3 The boiler is to be started in the normal manner following the cold start up procedure. All

normal recommendations and limitations with respect to fuel firing equipment, draft

plant, drains and vents, minimum instrumentatioin, interlocks and protections etc. should

be taken care of, as if the unit is started to synchronise the generator with grid.

1.4 Scheme : The steam blowing is done in four stages. Please refer to the scheme attached here with. Loop pipe

in between HP/IP control valves and HP/IP casings are not steam blown but adequate care should

be taken during erection to ensure cleanliness.

Systems covered in each stage are as follows :

1.4.1 Stage one : Super heaters and main steam lines upto HP stop cum control valve.

1.4.2 Stage Two : Super heaters, main steamlines and cold reheat lines. During last few blows

the HP bypass lines will be included in parallel. If necessary HP bypass lines can be

blown separately also.

1.4.3 Stage three : Super heaters, main steam lines, cold reheat lines, reheater, hot reheat lines

and upstream of LP bypass.

1.0 STEAM BLOWING :

1.1 General The purpose of steam blowing is to remove scales loose material, iron cutting etc. that might have

been entraped in super heaters, reheaters and related piping during manufacture, storage and

erection at site. Failure to remove the debris may result in damage to the turbine blades, valves etc.

1.2 Basic Technique :

POWER CYCLE PIPING

ERECTION

The steam blowing is carried out by puffing method. This technique will give a thermal shock to the

contour being purged to dislodge the scale etc. which will be subsequently cleared by the expanding

steam.

1.3 The boiler is to be started in the normal manner following the cold start up procedure. All

normal recommendations and limitations with respect to fuel firing equipment, draft

plant, drains and vents, minimum instrumentatioin, interlocks and protections etc. should

be taken care of, as if the unit is started to synchronise the generator with grid.

1.4 Scheme : The steam blowing is done in four stages. Please refer to the scheme attached here with. Loop pipe

in between HP/IP control valves and HP/IP casings are not steam blown but adequate care should

be taken during erection to ensure cleanliness.

Systems covered in each stage are as follows :

1.4.1 Stage one : Super heaters and main steam lines upto HP stop cum control valve.

1.4.2 Stage Two : Super heaters, main steamlines and cold reheat lines. During last few blows

the HP bypass lines will be included in parallel. If necessary HP bypass lines can be

blown separately also.

1.4.3 Stage three : Super heaters, main steam lines, cold reheat lines, reheater, hot reheat lines

and upstream of LP bypass.

POWER CYCLE PIPING

ERECTION

iii) For thermal expansion of the pipe, proper allowance must be given. First steam blow in every stage

should be given at lower pressure, Say 25 kg/ cm2 at boiler drum, to check the pipelines. Steam

blowing piping including temporary piping is surveyed for proper expansion.

iv) The furnace exit gas temperature should be limited to 540°C to safeguard super

heater and reheater tubes.

v) Sufficient storage of dimineralised water should be ensured and the rate of make up water to

feed tank is to be matched, taking into account the capacity of feed tank.

vi) Internal boiler water treatment to be carried out with liquid Ammonia and Hydrozene only, to

maintain a PH value of 10.0 in boiler water and 5 to 25 ppm of NgH^ in feedwater. Total dissolved

solids in boiler water should not exceed 10.0 ppm before going for steam blowing. If it is more,

rinse the boiler till it comes down to less than 10 ppm.

vii) Hot tightening of flanges, studs/bolts is to be done wherever such connections have

been made, including drain manhole door bolts.

viii) All the drains of connecting piping are, to be left open to atmosphere and not to be connected

to drain vessels, to ensure proper and quick draining. After checking the drain pots for chocking, the

drain lines are connected permanently to the vessel

ix) It should be ensured that all permanent hangers of the various lines should have been erected as

per drawing and all valves set accordingly to the design figures. Also should be ensured that locking

of the supports done for the purpose of hydraulic to etc. has been released before steam blowing.

x) The steam strainer elements to be removed in the main steam, hot reheaters

extractions lines to BFPTD prior to steam blowing.

xi) It should be ensured that hydraulic test of the reheater is completed before starting the stage III

steam blowing. After hydrotest remove the attemperator and lay the temporary exhaust pipe for

stage II as per the scheme.

POWER CYCLE PIPING

ERECTION

xii) Extra long thermo wells should be provided only after completion of steam blowing operation.

xiii) Jet breaker provided in the downstream of HP bypass should be erected only after completion

of steam blowing.

xiv) Down stream of LP bypass should be cleaned manually.

xv) Any loops coming in the lines during blowing should be 'inspected afterwards for cleanliness.

xvi) Spares strainer gaksets of M5 and RH system should be arranged.

xvii) To reduce the normal and reverse stress in the steam genertor and steam piping

number of blows have to be minimised. This will be possible by having relatively

clean critical piping, proper welding procedures and clean temporary steam blowing

piping.

1.7 Results :

The colour of the steam discharged to atmosphered can be used in indication of the debts being

removed from the contour. In addition, the aberations on the polished mild steel target plates in the

exhaust piping will be used to indicate the effectiveness of blowing. So after materials like

Aluminium, brass, copper etc. can also bne used for target plates.

For the first few blows in each stage target plate need not be kept. Afterwards these plates are fixed

in both branches of the exhaust pipes as per the arrangement. These target plates should be fitted on

straight portion of temporary piping as near as possible to permanent. These target plates are to be

inspected and properly identified by punching or engraving. For every subsequent blows new plates

should be used for both the branches.

1.8 Note :

1. Aux, steam lines, eminating from Aux. PRDS header, which are required to be ready before

boiler first light up are to be blown using steam from external source.

POWER CYCLE PIPING

ERECTION

2. Any other auxiliary pipe lines are steam blown by continuous blowing at appropriate stages

wherever these lines are made ready, at about 50% of the operating pressure of the line/system.


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

DO’S & DON’TS

IN PCP


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

Do-s :

Q Follow contract stipulations.

Q Follow storage and preservation instructions for materials while in custody.

Q Obtain all relevant drawings and documents required for execution of work.

Q Erect as per applicable drawings, reference documents, Quality Plans and authorised

instructions of BHEL.

Q Use calibrated IMTEs. Calibrate from BHEL approved sources.

Q Measure and examine construction tolerances achieved of buildings, steel framings and

connection points. Integrate the tolerances in the piping layout and correct relevant piping

component at the prefabrication yard at Site.

Q Study erection drawings and decide in advance whatever preassemblies may be made at

site before lifting components in position.

D Take up with BHEL if any mistake is detected or problem is foreseen.

Q Visualise any possible interferences with structures, ducts, cable trays, supports or any

other item before laying out the piping for timely corrective action.

Q Check piping component for damage/unsuitability, if any, before use. Report to BHEL for

corrective action.

Q Unpack control valve shortly before installation. The accessory items (solenoid valve,

control and blocking elements) should be stored dry and seal until final mounting to the valve.

Q Remove gland packings from control valve, if its installation after despatch from works is

going to be delayed. After removing the gland packings, repack the control valve and store it in

its original crate.

Q Remove gland packings from installed control valve, if its commissioning after


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

installation is going to blowing with compressed air air or steam as relevant. Wire brush

following blowing, if required.

Q Ensure cleanliness of piping components before pre-assembly/installation by mechanical

means or by blowing with compressed air or steam as relevant. Wire brush following blowing, if

required.

Q Instal items susceptible to damage from steam blowing action (flow nozzle, orifice, extra-

long thermo wells etc. in steam lines) only after steam blowing is over.

D Instal items (breakdown orifice in boiler feed re-circulation line etc)/Remove internals (of control

valve, strainer etc) susceptible to corrosion/deterioration from contract with flushing/chemical

cleaning medium only after flushing/chemical cleaning is over.

Q Take care of the direction of flow marked on the body of piping component (globe valve,

non-return valve, control valve, flow nozzle, orifice, trap, desupreheater etc) in the installation.

Q Instal flanged valves with the disc in the fully closed condition.

DO-s and Don't-s in Power Cycle Piping and Turbine Integral Piping Erection

Do-s :

Q Follow contract stipulations.

Q Follow storage and preservation instructions for materials while in custody.

0 Obtain all relevant drawings and documents required for execution of work.

Q Erect as per applicable drawings, reference documents, Quality Plans and authorised

instructions of BHEL.

Q Use calibrated IMTEs. Calibrate from BHEL approved sources.

Q Measure and examine construction tolerances achieved of buildings, steel framings and

connection points. Integrate the tolerances in the piping layout and correct relevant piping

component at the prefabrication yard at Site.


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

Q Study erection drawings and decide in advance whatever preassemblies may be made at

site before lifting components in position.

Q Take up with BHEL if any mistake is detected or problem is foreseen.

Q Visualise any possible interferences with structures, ducts, cable trays, supports or any

other item before laying out the piping for timely corrective action.

Q Check piping component for damage/unsuitability, if any, before use. Report to BHEL for

corrective action.

Q Unpack control valve shortly before installation. The accessory items (solenoid valve, control and

blocking elements) should be stored dry and seal until final mounting to the valve.

Q Remove gland packings from control valve, if its installation after despatch from works is

going to be delayed. After removing the gland packings, repack the control valve and store it in

its original crate.

Q Remove gland packings from installed control valve, if its commissioning after

installation is going to be delayed.

Q Ensure cleanliness of piping components before pre-assembly/installation by mechanical

means or by blowing with compressed air or steam as relevant. Wire brush following blowing, if

required.

Q Instal items susceptible to damage from steam blowing action (flow nozzle, orifice, extra-

long thermo wells etc. in steam lines) only after steam blowing is over.

Q Instal items (breakdown orifice in boiler feed re-circulation line etc)/Remove internals (of

control valve, strainer etc) susceptible to corrosion/deterioration from contract with

flushing/chemical cleaning medium only after flushing/chemical cleaning is over.

Q Take care of the direction of flow marked on the body of piping component (globe valve,

non-return valve, control valve, flow nozzle, orifice, trap, desupreheater etc) in the installation.

Q Instal flanged valves with the disc in the fully closed condition.


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

Q Erect pipes with radiographic plug in top position for effective venting.

Q Erect horizontal steam pipes and drain pipes with slope (towards drainage points) as

specified.

Q Route small bore piping economically and aesthetically taking care of supporting, flexibility,

drainage and schematic requirements.

Q Group site-routed small bore piping wherever practicable.

Q Prepare drawings for site-routed piping and obtain approval from BHEL.

Q Number weld-joints in any piping erection drawing sequential for easy traceability.

Q Clean weld ends to remove paint, oil, grease, rust, sand, earth and any other foreign matter.

Ensure dryness of joining ends before' weld commencement.

Q The weld-joint near any rotating equipment such as turbine, pump etc. should be the last to

be welded ensuring a floating condition before welding.

Q Keep valves in partially open position while welding with pipeline. Close the valve after

welding and heat treatment, if any, are over.

Q Remove combustible materials from the vicinity of welding or gas cutting operation. ID

Wear safety goggles while chipping, grinding or removing slags. Q Use electrodes specified

from sources approved by BHEL.

Q For socket-welded joints, maintain a gap of 1-1.5 mm between the socket seat and the edge

of the item inserted.

Q Seal weld the radiographic plug used for venting during hydro-test. Q Clean exposed

welded surfaces of slag and paint with primer to prevent corrosion.

Q For ultrasonic examination of weld-joint, grind sufficient length from centreline of weld-

joint on either side to a smooth finish.

0 Use the designated lifting lugs if any provided for lifting any heavy piping component

(valve, bellows expansion joint etc.). Otherwise, use slings.


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

Q Remove any foreign material that may have lodged between the convolutions of a bellows

expansion joint.

Q Install specifically fabricated insert in the internals of HP Bypass valve before steam

blowing.

Q Check access requirements for operation/maintenance of valve before welding the same.

Consult BHEUCustomer, if modification required.

Q Blank off stubs on piping, if any. provided without valve for entry of flushing fluid after

flushing is over.

Q Identify valve properly with respect to type, rating, size, material etc and clean using

compressed air before erectiion.

Q Instal swing or piston check valve with valve cover facing upwards.

Q Check flange faces for proper condition of gasket contact surface required.

Q Check gaskets for proper condition.

Q Follow recommended flange bolt tightening procedure for even loading.

Q Remove blocking provided in swing check valves or any other component before putting in

service.

Q Clean interior of both valve and connecting piping thoroughly so as not to leave any weld

spatter or any other foreign matter.

Q Instal globe valve such that the incomming fluid faces the bottom of the disc.

Q Straddle flange bolt holes symmetrically with installed centreline unless required otherwise

to match equipment connection.

Q Cover exposed machined surfaces of flanges, valves and also small bore screwed fittings by

an adequate film of heavy grease.

Q Graphitise gasket with ready-mixed compound or mixture of heavy cylinder oil and

graphite flake before installation.



Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

0 Before applying insulation, ensure that surface is dry, clean, free from grease, loose scale.

Q On new installation, tighten each bolt joint nut once or twice to prevent leakage, if any, after

steam has initially passed the valve.

Q Contact BH EL in case of any doubt regarding the above instructions or in case further

clarity is required.

Q In case of differences between any of the above instructions and instructions given in the

authorised contract documents, those in the contract documents shall prevail. However,

any such difference should be reported to BHEL.


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

Dont's :

Q Do not use any plant material (angle, channel, handrail, piping component) for use as

temporary support or scaffolding work or for making a pre-assembly bay.

Q Do not use any nonconforming component without taking action as per authorised

disposition.

Q Do not stretch, compress or offset any bellows expansion joint to fit the piping.

0 Do not use bypass piping (when provided) or handwheel of valve for lifting the valve or

any other component.

Q Do not use welders not duly qualified for a particular job.

Q Do not weld while wearing wet gloves or shoes.

Q Do not look at electric arc with naked eye.

Q Do not delay NDE for weld-joints.

Q Do not hold hydro-test pressure for more than 30 mintues.

0 Do not remove lock pin from spring hangers before hydro-test or chemical cleaning is over.

D Do not cover vent holes provided on high pressure valves while insulating.

Q Do not steam blow uninsulated lines.

0 Do not charge any line with its vents and drains closed.

Q Do not charge a line with its hangers in locked condition.

Q Do not insulate stuffing box areas of valves.


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

QUALITY CHECKS FOR

PIPING ERECTION


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

Q Check the location and disposition of terminal points.

Q Identify the components and check for statutory agency clearance.

Q Check the completion of supporting structure for pipe lines.

Q Ensure the cleanliness of pipe line before erection.

Q Ensure the erection completion of hangers before the erection of pipe line.

Q Ensure that the radiography plugs are in top position while erection.

Q Check the elevation, disposition and slope of the pipe lines and record.

Q Ensure sufficient gap around the pipe lines with structure/wall to accommodate the

insulation thickness and expansion provision during operation.

Q Check the welders' performance qualification records.

Q Ensure adoption of correct procedure, approved electrodes and methods.

Q Check the fit up of the joints, orientation and alignment of piping.

Q Identify the weld joints and ensure maintenance of records indicating number of joints,

details of NDE and heat treatment carried out. Also maintain reccords on number of

joints accepted or rejected and on repair details.

Q Check the erection completion of all drains, vents, impulse and sampling lines and seismic

guides.

Q Ensure removal of temporary supports and completion of permanent supports.

Q Ensure that all the safety valves are provided with hydrostatic test plugs before hydrostatic

test and after hydrostatic test ensure that discs are replaced.

Q Check the completion of insulation. Q Check the verticality and loading of all the

suspensions.


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

Q Check the cold compression values of all springs and ensure locking of the spring assembly.

Q Check the completion of all pressure parts attachment welds. Q Check

the erection completion of all drain/vent valves.

Q Ensure servicing of valves by checking freeness in operation (manual/electrical), greasing of

threaded parts, adequacy of packing gland etc. -

Q Check the seal welding of all site radiography test plugs.

Q Ensure locking of all supports before hydrostatic test and releasing after hydrostatic test.

Q Ensure erection completion of temporary piping for chemical cleaning and steam blowing.


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

ACCEPTANCE CRITERIA FOR PIPING ERECTION

ERECTION TOLERANCE

Characteristic Tolerance

Edge preparation out-of-squareness for TIG. welding 0.8 mm

Misalignment at root

• For pipe bore less than 150 mm and pipe wall 6 mm or less

• For pipe bore 150 mm upto 299 mm and pipe wall + or -

1.2 mm thickness 6 mm upto 10 mm.

• For pipe bore 300 mm and above and pipe wall + or - 1.6 mm above 10 mm

1.

2.

+ or - 0.8 mm


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

3.

4.

5.

6.

7.

8.

9.

10.

11.

Angle of bend

Alignment of flanges or ends deviation from indicated

position measured across any diameter.

Rotation of flanges from indicated position Bend

ovality

Pipe end ovality

Percentage thinning on bends

Disposition of pipes

Elevation of pipes Slope of

the pipes

+ or - 1/2 degree 1 mm

per 300 mm

1.5 mm (Max.)

< 8% of OD (<20D/R)

where D - OD

R - Radius of bend

+1% of OD (Max.

of 4 mm)

< 10% of 't' nominal

plus Neg. tolerance of 't'

nominal.

+ or - 5 mm +

or - 5 mm


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

ERECTION WELDING

PROCEDURE FOR SA 335

P-91 MATERIAL


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

1.0 SCOPE

This document details salient practices to be adopted during erection of SA335 P91

material.

2.0 MATERIAL

Materials shall be identified as follows.

1) Colour Code: Brown & Red

2) Hard Stamping: Specification, Heat No, Size.

3) Paint / Stencil: WO DU, as per the relevant drg & document

2.1 When any defect like crack, lamination, deposite noticed during visual examination the

same shall be confirmed by Liquid Penentrant Inspection. If confirmed, same shall be referred to

Unit.

3.0 ERECTION

3.1 Edge Preparation and fit up

3.1.1 Cutting of P-91 material shall be done by band saw / hacksaw / machining / Plasma Cutting /

grinding only.

Edge preparation (EP) shall be done only by machining. In extreme cases, grinding can

be done with prior approval of Welding Engineer/Quality Assurance Engineer. During

machining / grinding, care should be taken to avoid excessive pressure to prevent

heating up of the pipe edges.

3.1.2 All Edge Preparations done at site shall be subjected to Liquid Penetrant Inspection (LPI).

Weld build-up on Edge Preparation is prohibited

3.1.3 The weld fit-up shall be carried out properly to ensure proper alignment and root gap.

Neither tack welds nor bridge piece shall be used to secure alignment.

Partial root weld of minimum 20mm length by GTAW and fit-up by a clamping

arrangement is recommended. Use of site manufactured clamps for fitup is acceptable.

The necessary preheat and purging shall be done as per clause 3.4.1. and 3.2.2.


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

3.1.4 The fit-up shall be as per drawing. Root gap shall be 2 to 4mn; root mismatch shall be within 1

mm. Suitable Reference punch marks shall be made on both the pipes [at 200mm from the EP]

at least on four axis to facilitate U.T. on weld joint.

3.2.0 FIXING OF THERMOCOUPLE (T/C) AND HEATING ELEMENTS DURING

PREHEATING AND PWHT

3.2.1 No Preheating is required for fixing T/C with resistance spot welding Followmg are the

equipment / facilities for heating cycles.

(1) Heating methods : Resistance heating or induction heating for thickness upto

and including 25mm.

Induction heating for thickness above 25mm.

(2) Thermo couples : Ni-Cr/Ni-AI of 0.5 mm gauge size.

(3) Temp. Recorders : 6 Points/12 Points.

3.2.2 ARRANGEMENT FOR PURGING :

Argon gas shall be used for purging the root side of weld. The purging dam (blank) shall be fixed

on either side of the weld bevel prior to pre-heating. The dam shall be fixed inside the pipe and it

shall be located away from the heating zone. Purging is to be done for root welding (GTAW)

followed by two filler passes of SMAW in case of butt welds. Purging is not required in the case

of nozzle and attachment welds. The Argon to be used shall be dry. The flow rate is to be

maintained during purging is 10 to 25 litres/minute and for shielding during GTAW is 6 to 10

litres/minute.

Start purging from inside of pipe when root temperature reaches 220deg C Provide continous and

Equate Argon Gas to ensure complete purging in the root area.

The minimum pre-flushing time for purging before start of welding shall be 5 minutes, irrespective

of the pipe size.

Use of alternative gas purging in case of non availability of argon shall be done only after prior

approval from WTC / PC.


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

Wherever possible, solid purging gas chambers are to be used which-can be removed after

welding. If it not possible, only water-soluble paper is to be used. Plastic foils that are water-

soluble are NOT acceptable.

3.2.3 USING ALUMINIUM DAM ARRANGEMENT:

In order to retain the Argon gas at the inside of the pipe near root area of the weld joint, the

purging dams made of Aluminium and permanite gaskets may be provided during the weld fit-up

work as indicated in the sketch.

The Aluminium discs shall be firmly secured with a thin wire rope. After completion of the root

welding followed by two filler passes, the disc may be pulled outwards softly.

SKETCH

CAUTION: ENSURE REMOVAL OF PURGE DAM ARRANGEMENT AFTER WELDING.

Using water soluble paper

The dams can be made of water-soluble paper for creating the purging chamber. The advantage in

such dam arrangement is that dissolving in water can flush the dams. The following are different

methods.


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

The purge damming process is illustrated as below

1. For small diameter pipes, simply stuff water soluble paper into each section to be joined

(Refer sketch)

2. For larger pipes, cut out a circular disck slightly larger than the diameter and shape it to

the inside pipe circumference. (A small hole may be punched in the paper to ensure complete

evacuation of air when purging) (Refer sketch)

3. Position the disc within the pipe and tape in place with water soluble paper. Repeat

procedure for the other section. Insert the backing gas into the joint with a needle

valve and make root pass in the usual manner. (Sketch)

4. For pipes larger than 508 mm diameter, simply splice two sheets of water soluble paper

together with water soluble wat. and repeat procedure in picture 2 and 3. (Sketch)

SKETCH-1

SKETCH-2

SKETCH-3


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

4.0 WELDING/ WELDERS QUALIFICATION :

Only qualified welding procedures are to be used. Welders Qualified as per ASME Section IX and

IBR shall only be engaged Welders log book to be maintained and welders performance to be

monitored by site Welding engineer/ Quality assurance engineer.

4.1 PREHEATING

Prior to start of pre heating ensure that surfaces are clean and free from grease, oil and dirt.

Preheating temp shall be maintained at 220 deg C (min) by using Resistance heating / Induction

heating for pipe wall Thickness upto and incuding 25 mm, and INDUCTION HEATING for

thickness above 25 mm. The Temperature shall be ensured by using a Calibrated autographic

recorder and two calibrated thermo couples fixed at 0 deg and 180 deg positions on both pipes 50

mm away fiom the EP. The thermocouple shall be welded with the spot welding machine. The pre

heating arrangements shall be inspected and approved by welding engineer / Quality Assurance

Engineer. ( Ref Fig - la & Ib)

Alternate arrangements shall be made during power failure. Two additional spare thermocouple to

be fixed (as described above) for emergency use. Gas burners shall be employed to maintain the

Temperature until the power resumes.

4.2 WELDING: Root Welding shall be done using GTAW process (as per WPS) five minutes after the start of

argon purging. Filler wire shall be clean and free from rust or oil. Argon Purging shall be

continued minimum two filler passes of SMAW.

4.3 The electrode issued to the welders should be controlled through issue slips. SMAW

electrodes used must be dried in drying ovens with calibrated temperature controller.

The drying temperature shall be as recommended by the electrode manufacturer. The

drying temperature shall be 200 - 300 deg C for two hours if it is not specified by the

manufacturer.

Portable flasks shall be used by the welders for carrying electrodes to the place of use. The

electrodes shall be kept at 100 deg C in the flask.

Welding shall be carried out with short arc and stringer bead technique only.


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

4.4 The inter-pass temperature shall not exceed 350 deg C. After completion of Welding bring down the

tamperature to 80 - 100 deg C and hold it at this tamperature for one hour minimum. The PWHT

shall commence after completing one hour of soaking.

5.0 POST WELD HEAT TREATMENT

Arrangements :- A minimum of four thermocouples shall be placed such that at least two are on

the weld and the other two on the base material on either side of the weld within the heating band

at 180 degrees apart about 50mm from the weld joint. One standby thermocouple shall also be

provided on the weld in case of any failure of the thermocouple. The width of the heated

circumferential band on either side of the weld must be atleast 5 times the thickness of the weld. In

case of fillet joints the heating band shall be six times the thickness of the base material. (Ref Fig -

2a & 2b) For induction heating, an insulation of about 10mm thickness shall be provided between

the cable end weld joint.

5.1 Obtain the clearance for post weld heat treatment cycle from QAE / Welding Engineer.

The PWHT temp shall be 760 +10 deg C and the soaking time shall be 2.5 minutes per

mm of weld thickness, subject to a MINIMUM OF TWO HOURS. All records shall be

reviewed by Welding Engineer prior to PWHT clearance. Heating shall be done by

Induction heating for pipe / Weld Thickness above 25 mm. For 25mm and below

resistance / Induction heating method can be employed.

The rate of heating / cooling :- Thickness up to 50mm 110 dog C / hr.(max) (above 350 deg C)

Thickness 50 - 75mm 75 deg C / hr.(max)

Thickness > 75mm 55 deg C / hr.(max) Thickness = Actual thickness as measured.

5.2 INSULATION: The width of the insulation band beyond the heating band shall be at least

two times the heating band width on either side of the weldment.

The recording of time & temperature shall be continuously monitored with a calibrated recorder

right from preheating. This will be ensured at every one hour by site authorized personnel.


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

5.3 PREVENTIVE MEASURES DURING POWER FAILURE AND NON-

FUNCTIONING OF EQUIPMENTS.

No interruption is allowed during welding and PWHT. Hence all the equipment for

the purpose of power supply, welding, heating etc., shall have alternative

arrangements.

(diesel generator for providing power to the welding and heating equipments, standby

welding and heating equipments, reserve thermocouple connections, gas burner

arrangement for maintaining temperature etc.) Following preventive measures shall be

adopted until normal power supply or backup power supply through diesel generator

is restored.

(a) During start of preheating:

Weld fit-up arrangement shall be immediately covered with insulation along the complete

circumference of the pipe and maintained at the temperature 80 - 100 deg C until the power

resumes. The temp shall not be allowed to fall below 80°C. Gas burners shall be employed to

maintain the temperature till power resumes. Preheating may be continued after power is resumed /

alternative arrangement is made. (Ref: Fig 3)

(b) During GTAW / SMAW :

Use gas burner arrangement to maintain the temperature at 80 deg - 100 deg C upto a length of 50

mm on either side from weld centre line along the complete circumference of the pipe. Root

welding shall be continued after power is restored and preheating temperature is raised to 220 deg

C. During the above period temperature shall be recorded through contact type thermometer. (Ref:

Fig4)

(c) During cooling cycle after SMAW welding to holding temperature at 80 to 100

deg C for one hour. ( Ref: Fig 5)

Care shall be taken to avoid faster cooling rate by adequate insulation. The required temp 80 - 100

deg C shall be maintained by gas burner arrangements till power resumes / start of PWHT.


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

e) Soaking at PWHT

f) Cooling to 350 Deg C

g) Cooling to Room Temperature (under insulation)

5.6 CAUTION

THE PWHT TEMPERATURE SHALL NOT DEPART FROM THE VALUES SPECIFIED IN

THE CHART RANGE SINCE ANY DEVIATIONS TO SPECIFIED HOLDING

TEMPERATURE RANGE, WILL ADVERSLY AFFECT THE MECHANICAL PROPERTIES

OF THE WELDMENT AND MAY LEAD TO REJECTION OF THE WELDMENT. THE

WELD JOINTS SHOULD BE KEPT DRY. UNDER NO CIRCUMSTANCES ANY

WATER/LIQUID IS ALLOWED TO COME IN CONTACT WITH WELD AS WELL AS

PREHEATED PORTION OF PIPE.


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

5.7 CALIBRATION All equipments like recorder, thermocouple, compensating cable, oven thermostat etc.

should have valid calibration carried at BHEL approved labs. - The calibration reports

shall be reviewed and accepted by Calibration In-charge at site prior to use.

6.0 NONDESTRUCTIVE EXAMINATION:

6.1 All NDE shall be done after PWHT only.

6.2 Prior to testing all welds shall be smoothly ground. All welds (fillet & butt) shall be

subjected to MPI (MPI shall be done by YOKE type only) In addition to MPI, butt-welds and all

full penetration welds shall be examined by UT.

6.3 The UT procedure shall be as per BHE:NDT:PB:UT21- Rev 03 LPI Procedure, shall be

NDE:PT:01-Rev 00 and MPI procedure shall be BHE:NDT:PB:MT:05-Rev 02 The chemicals used

in MPI / LPI shall be of BHEL approved makes only. The UT equipments shall be of recorder type

and be calibrated prior to use. All butt welds and full penetration welds shall be examined as per

procedure by a qualified operator as per SNT-TC-1A or equivalent. The interpretation will be done

by Level II qualified personnel as per ASNT-SNT-TC-1 A or equivalent. The NDE report should

have all the details as per procedure. Any defect noticed during NDT shall be marked with marker.

7.0 REPAIR OF WELD JOINTS:

(A) WELD REPAIR AT ROOT. On visual examination during root welding if it reveals any surface defects, the same

shall be removed by grinding maintaining temperature 80 - 100 deg. C and rewelded

tenth GTAW maintaining 220 deg. C before starting SMAW.

(B) WELD REPAIR ON COMPLETION:

Any defect observed on the weld shall be brought to the notice of Quality assurance

engineer. The size and nature of defect shall be reviewed. Any repair on weld to be

earned on their approval only.


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

If any defects are noticed on the fully completed weld while performing U.T after

completion of PWHT, the same may be assessed in order to find the seriousness of the

defect and to locate where exactly the defect lies from the weld outside surface. The

defect area shall be marked and repaired as below:

a) The weld shall be removed by grinding (gouging not permitted) such that the area for repair

welding is free from sharp corners and provided with sufficient slope towards the weldface sides.

Incase of cut & weld joints HAZ (= 5mm) will have to be removed by grinding.

b) Surface examination (MPI/LPI) on the ground weld area to be perfommed to ensure a sound

base metal before depositing weld layers using SMAW.

c) The temperature of the weld is to be maintained at preheat temperature.

d) Carry out SMAW using the same procedure as that of welding.

e) All the specified precautions w.r.t to welding consumables, heating cycles, post weld heat

treatment etc. as followed for original welding, shall be strictly adhered.

f) The NDE shall be conducted for the entire weld joint.

g) If any further defects are observed on the repaired weld, the same may be further reworked as

mentioned above.

8.0 HARDNESS SURVEY The equipment recommended to measure the hardness are EQUOTIP or MICRODUR

make or equivalent portable equipment.

The equipment used for the hardness measurement shall be calibrated as recommended

by the manufacturer and also on a P91 calibration block provided by Piping Centre.

The surface shall be cleaned and prepared as per hardness test instrument manufacturer's

recommendation prior to hardness survey.

Hardness survey shall be done at each joint at three locations along the


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

circumference. At each location three readings on weld and parent metal (both pipes) shall be

carried out.

All the hardness values shall be recorded.

The max allowable hardness at weld and parent metal shall be 300 HV10. Joints having hardness

above 300 HV shall be reheat treated and hardness shall be checked again. If hardness is still more

refer to unit.

PMl WELD

Figure-10

LOCATION

PM1

WELD

PM2

READINGS

1 2 3 AVE

1 2 3 AVE

1 2 3 AVE

0

90

180

270

PM: PARENT MATERIAL AVE : AVERAGE

9.0 COMBINATION WELDING

For other combination of material like P22 with P91, WPS as approved by WTC shall be given by

PC for adoption.

However the precautions as required for P91 shall be fully taken care of. 10.0

DEMAGNETISATION

In case magnetization is noticed on the pipes, the following procedure shall be Followed during

welding.

PM2

270


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

Use Residual field-indicator at one end of pipe and measure the residual field. Note reading and

direction of field (+ ve or - ve & No units)

+101- 0 -10

Indicator may show readings greater than + or -10 Divisions. A small size electrode or gem-clip

will get attracted & stick to pipe.

Wrap insulated welding cable - 5 turns-clockwise on the OD surface or pipe. Wrapped cable to be

50 to 100 mm away from joint end.

One cable - end connect to +ve terminal of welding generator and the other to-ve terminal.

Complete electrical circuit & pass 400 amps current for 3 to 4 seconds.

Measure residual field now at the same end of pipe.

If demegnetisation is effective the reading will come closer to '0'

For eg. If it is formerly > + 10 Divns, it may show -5 Divn.

The electrode or gem-clip will not stick to pipe-end.

If de-magnetisation is NOT effective

The readings will be greater in the same direction

The gem - clip/eleclrode will skill stick to pipe, Then repeat the following.

Now wrap the insulated cable (5 turns ) in anti-clockwise direction pass current slightly excess of

400 Arnps

Reduce the current gradually to 0 amps in one minute when current is on. Check for

demagnetization using gem-clip/electrode. The gem-clip/electrode WILL NOT GET attracted.

If the reading is shifted to opposite direction, reverse the turns.


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

11.0 TRAINING

11.1 SELECTION OF WELDERS

Welders who are already qualified for P22 welding and with proven Records will be selected for

training on P91. They will be identified exclusively with welder numbers.

•11.2 Welders shall be trained by WTC/WRI and qualified for P91 welding. 1'1.3

CONTROL ON WELDERS

The welder during welding at site follow the following procedures.

The welder shall interact with the HT operator (Induction / Resistance equipment operator) to

ensure that preheat and interpass temperature during welding are maintained as per requirements.

The welder shall not mix the welding electrodes with that of the other welder. At the end of the

shift, the unused electrodes shall be returned to the stores.

11.4 PERSONNEL / CONTRACTORS ENGAGED FOR HEATING CYCLES (HT Operator)

11.4.1 The Personnel / Contractor shall have adequate heat treat experience on P91 or similar

material.

11.4.2 HT operator shall be aware of the following:

a) The equipment used and its working principle and operation.

b) The procedures to be followed in using heating equipments.

c) Procedure to be followed in case of power failure or equipment non-functioning so

that heating cycle is not disrupted.

d) Calibration of equipments.

e) Method of fixing thermocouples and compensating cables leading to HT recorder.


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

f) Fixing of heating pads or elements on the pipe joints and also in maintaining the

temperature within the specified limits.

11.5 NDE PERSONNEL QUALIFICATIONS

All NDE personnel performing NDT like UT & MPI/LPI shall be qualified in

accordance with ASNT-SNT-TC-IA.

UT, MPI &-LPI shall be carried out be level I qualified personnel and shall be

evaluated by level II qualified personnel.

11.6 LEVEL OF SUPERVISION

Site Incharge shall be responsible for the completion of all activities from weld fit-up

to final clearance of weld joints after satisfactory NDE and acceptance by

BHELVCustomer/IBR.

12.0 DO's and DON'T' s during P 91 welding, heat treatment and NDE at construction site.

12.1 DO'S .

a) Cutting by Band saw/Hack saw/Machining/Plasma cutting

b) Pipes Edge Preparation by machimng Machining shall be done without excessive pressure to

prevent heating up of pipe

c) Grinding may be done on exceptional cases taking adequate care to prevent overheating.

d) Thermocouple wire (Hot/Cold junctions) shall be welded with condenser discharge protable

spotwelding equipment.

e) Reserve Thermocouples shall be made available, incase of failure of connected thermocouple

elements.

f) Ensure adequate Argon Gas for complete purging of air inside the pipe before starting

GTAW root welding.

g) . Ensure Preheating at 220 Deg.C minimum before GTAW root welding.


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

h) Start preheating only after clearance from Welding'engineer / Quality assurance engineer

for weld fit-up and alignment of the joint as well as fixing of Thermocouple

connections ( for Induction heating)

i) Do visual inspection on root weld n~irda~g weld preheating temp;

j) Continue Argon purging until the GTAW root welding followed by minimum two filler

passes of SMAW, is completed.

k) Perform partial root welding to facilitate fit-up if necessary.

1) Ensure that only one layer of root welding using TGS 2CM filler wire (2 1/4 Cr 1 Mo) is

deposited, (wherever specified).

m) Ensure proper use of TIG wires as identified by colour coding or suitable hard punching.

n) Keep the GTAW wires in absolutely clean condition and free from oil, rust, etc.

o) Dry the SMAW electrodes before use.

p) Ensure the interpass temperature is less than 350 Deg.C.

q) Hold at 80-100 Deg.C for a period of Minimum I hour before the start of PWHT.

r) Record entire heating cycle on Chart though recorders.

s) Exercise control during grinding of weld and adjoining base metal while removing

surface/sub surface defects or during preparation for NDE.

t) Ensure no contact with moisture during preheat, welding, post heat and PWHT of Weld

Joints.

u) Ensure removal of argon purging arrangements after welding. 13.0

DON.Ts

a) Avoid Oxy-Acetylene flame cutting.

b) Avoid Weldbuild up to correct the weld end-d1 or to set right the lip of the weld


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

bevel.

c) Avoid Arc strike on materials at the time of weld fit up or dunug welding.

d) Do not Tack weld the Thermocouple wires with Manual Arc/DIC welding.

e) NO GTAW root welding without thorough purging of root area

f) Do not use Oxy-acetylene flame heating for any heating requirements.

g) Do not use Thermal chalks on the weld groove.

h) Do not stop argon purging till completion of GTAW root welding and two layers of

SMAW.

i) No Tack welding or Bridge piece welding is permitted.

j) Do not use unidentifiedTIG wires ordectrodes.

k) Do not exceed the maximum interpass temperature indicated in WPS

I) Do not allow moisture, rain, water, cold wind, cold drag etc. to come in contact with the

weld zone or heating zone during the entire cycle from preheat to PWHT.

m) Do not exceed the limits of PWHT soaking temperature. n) Do not Interrupt the

Welding/heating pycle except for -unavoidable power failures

o) Do not use uncalibrated equipment for temperature measurement during heating,

welding, post weld, heat treating etc.,

14.0 Documentations

The documentation shall be as per the customer approved / BELL Quality Plan.


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

PRECAUTIONS FOR X-20

& P-91 WELDING


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

PREPARATION AND SPECIAL PRECAUTIONS FOR X20 AND P91 WELDING

X20:-Preparation

X20 welding is quite different from the welding of other conventional piping materials. The

following preparations are considered essential before the start of work :-

Q Welders should undergo an orientation programme on X20. They should be trained in

X20 welding and then qualified by competent authority.

Q Where the contract is only for installation of Piping including X20, such orientation and

training should take place sufficiently ahead of the start of work at site or the sub-contractor

engaged should already have qualified X20 welder with him.

Q Entire heat treatment cycle including preheating, welding, stress relieving must be completed

in one cycle as cooling down to temperature below 100° C any time before stress relieving is

completed is detrimental for the material.

Q Provision is required for heating by alternate source in case of power failure during the

heating cycle to ensure that temperature of joint does not fall below 100°C.

0 Shop welding is recommended for transition pieces between dissimilar materials (practically

unavoideable) such that site welding is between similar materials only.

Q Low speed grinding intermitently is required against continuous high speed grinding for

conventional materials in order to ensure overheating does not take place.

Q RT of weld-joints is not practical. Ultrasonic test has to be carried out. Also, NDE

requirements are more exhaustive than in the case of conventional materials.

Q Electrodes and filler wires both required import. Q Dehumiditier or effective equivalent

required for proper storage of electrodes.

Q Baking oven to be suitable for baking electrodes at 300-350° C which is higher than the

baking temperature range for conventional materials.


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

Q Heating by induction is recommended for the entire heating cycle in case of heavier wall

components.

Q All parameters (preheat temp., welding temp., soaking temp and time, rate of cooling and

rate of heating) indicated in the applicable heat treatment cycle and other data given in

the welding procedure specification (WPS) must be strictly adhered to.

Q Use of following accessories is recommended for X20 welding :-

- Digital temperature indicator with probe, range 0-1200°C.

- Thermocouple attachments unit (Spot Welding Machine)

Q X20 welding using induction heating equipment requires stocking of a no. of

accessories/consumbles as follows :-

- at least one spare spot welding machine in addition to onesuch machine per welding

station.

- LPG gas or equivalent cylinder for emergency heating in case of prolonged power

failure.

Annealing furnace cables.

Programmable micro-processor based temperature controller, 0-1000°C. Medium frequency

water-cooled capacitor, 1200 KVA, 1250V AC, 3000 Hz. Special Precautions

Q Tack welding or arc strike on material at the time of fit-up or during welding is not

permitted. Mechanical type fixtures required for fit-up and alignment of butt-joints.

Q Cutting of pipe ends only by hacksaw or machine. While machining, pressure on the pipe to

be avoided to prevent overheating of the pipe.

Q Damages caused at lip or inside diameter of pipe end to be made good by re-machining only.

Q Pipe surface to be cleaned and filed at the spot where thermocouple is to be fixed.


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

Q Resistance spot welding is to be done for fixing thermocouple.

0 Argon for purging to be 99.97% pure. Purging has to be done for root welding (GTAW)

followed by two filler passes (SMAW).

Q Temperature during prehating and welding interpass temperature after each layer of

welding should be checked with portable digital temperature gauge in addition to the

heating cycle chart record.

0 Root weld to be visually inspected and if any surface defect is detected, the same is to be

removed by grinding maintaining the preheat temperature at 250°C.

Q After root welding, weld and HAZ area should be covered fully to ensure weather protection.

D No water or liquid should come in contact with the weld as well as HAZ of the pipe.

0 Welders must use portable electrode should not exceed 10 hours.

0 Electrode should be used within 4 hours after opening from their sealed container or after

taking from re-drying oven.

D After completion of welding, the same should be checked and covered immediately with

insulation up to the complete heated zone.

0 The weldment should be cooled to between 100 and 120°C (less than 100°C not allowed)

and soaked at the temperature for the specified length of time for complete

tranformation of austenite into martensite.

Q Heating cycle has to be continued till stress relieving is complete.

Q Minimum two t/c-s are to be fixed on centreline of weld before heating to PWHT temperature

for measuing PWHT temperature.

Q Continuous grinding is to be avoided to prevent overheating.

Q Welder should interact with annealer to ensure that interpass temperature during welding is

maintained within the specified range.

D Electrode arc striking is permitted only in the weld groove.


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

Q In case of a power failure during the preheating process, preheat temperature is to be matinained at

250°C and not falling below 100°C over an uncovered length of 50 mm on either side of the weld

using LPG or equivalent gas until power is restored.

0 During power failure while welding the root, root is to be covered immediately with

insulation and heating with LPG started to maintain temperature as in the earlier case until power

is restored when electrical power should be used to complete the root welding.

Q In case of power failure after welding but before cooling to between 100 and 120':)C, ensure that the

temperature does not fall below 100°C using gas as earlier specified.

Q In case of power failure during heating to attain PWHT temperature, the temperature should

be maintained at 100°C with specified gas burners at the complete heated zone until power is

resumed.

Q In case of power failure during PWHT period, weldment and heated portion of pipe should

be maintained at 300-350°C under insulation material using the gas. Prescirbed cooling rate

should not be exceeded during such operations.

P91 :-Preparations

Q Welders and annealers should undergo an orientation programme on P91. Welders should

be trained in P91 welding and qualified by competent authority.

Q Where the contract is only for installation of Piping including P91, such orientation and

training should take place sufficiently ahead of the start of the work at site or the su-contractor

engaged should already have qualified P91 welder with him.

0 In case induction heating is employed, the accessories and consumables to be stocked

should be as indicated for X20.

Q Standby provision for alternate source of power (diesel generator or gas-fired ring burner) is

not required in the event of power failure during P91 welding cycle since cooling to room

temperature may be permitted in case of P91.


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

Q Spot Welding Machine (Thermocouple Attachment Unit) for fixing thermowells is not a

must.

Q NDE requirements are not as exhaustive as for X20. However, hardness test for weld-joint

using ultrasonic method is required.

Special Precautions 0 Postheating of weld joint for 2 hours at 250°C is required on completion of welding before it

may be cooled to room temperature prior to heat treatment. Similar postheating requirement is

therefor conventional low alloy steel materials but the temperature is 150°C.

Q Moisture should not come in contact with weldment before PWHT of the same is over.

Q Dry conditions in the surroundings should be ensured when weld-joint is cooled to room

temperature after postheating but before stress relieving.

Q All the process parameters specified in the heat treatment diagram or the EWS are to be

strictly followed, however, as in the case of X20 materials.


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

ANNEXURE


Rev. 00 03/2000

POWER CYCLE PIPING

ERECTION

Erection Manual-pc Piping

Documents

Transcript of Erection Manual-pc Piping