standard specification for fabrication and erection of piping

STANDARD
SPECIFICATION FOR
FABRICATION
AND
ERECTION OF PIPING

CONTENTS
1. GENERAL
2. PRE-FABRICATION
3. ERECTION
4. LAYING OF UNDER GROUND PIPING
5. INSPECTION
6. TESTING
7. RECORDS
8. PAYMENT

Std. spec for earth work for U/G piping
Std. spec. for welding
Code for petroleum Piping ANSI B 31.3/IS 10234
piping
Code of procedure for manual IS: 823
Metal arc welding of mild
Steel for structural work.
Welder qualification ASME – Sec. IX
All codes referred shall be the latest editions. The contractor shall bear the cost of repair, changes,
replacements etc. due to non-compliance with the standards, codes and the tender or due to
disregard of the instructions given by the Engineer in charge.
2. PRE-FABRICATION
The contractor shall fabricate all pipe work in conformity with the requirements of pertinent general
arrangement drawing and specification. Where specific details of fabrication are not indicated
on the drawings or not specified herein fabrication and erection shall be done in accordance with
the code for petroleum refinery piping ANSI B 31.3 latest edition.
The contractor shall be reasonable for working to the exact dimensions as shown on the drawings
irrespective of individual tolerances permissible. Where errors and /or omissions occur on the
drawings, it shall be the contractor’s responsibility to notify the Engineer in charge prior to
fabrication or erection. Dimensional tolerance for fabrication shall be as per standard.
1. GENERAL
This specification is intended to cover the technical requirements for the execution of piping prefabrication,
assembly and erection of the entire pipe work defined hereunder for product /water
pipe line.
2. Scope
-Fabrication and erection of all piping systems from piping materials supplied by owner in
accordance with this specification and applicable drawings and standards.
-Testing and flushing
-Fabrication and erection of supporting elements i.e. shoes, guides, stop anchors, clips, cradles
etc. including applying one coat of red oxide zinc chromate primer.
-Fabrication and erection of supporting fixtures i.e. brackets, cantilever struts etc. including
application of one coat of red oxide zinc chromate primer.
-Coating & wrapping of underground piping.
-Fabrication and erection of drain assemblies.
-All piping systems shall be fabricated, installed, flushed, and tested in accordance with this
specification and applicable codes / drawings / standards. Any deviation from the specification
and drawing shall be permitted only after obtaining the written approval of the Engineer in
charge.
Applicable Codes & Standards
Std. Spec. for coating and Wrapping of U/G piping.

2.2 Alignment
The pipes to be joined by welding shall be aligned correctly with the existing tolerances on
diameters, wall thickness and out of roundness. The same alignment shall be preserved during
welding. For the internal misalignment due to difference in wall thickness of the mating
components exceeding 1/16”, the component with the higher wall thickness shall be internally
machined / grounded as per standard, so that the adjoining surfaces are approximately flushed.
2.4 Layout, Cutting & Fitting-up
For laying out headers, tees, laterals and other irregular details, cutting templates shall be used to
ensure accurate cutting and proper fit up.
All cutting shall follow the outline of the templates.
Machine cut bevels to form the welding groove are preferred in carbon steel pipe. However,
smooth, clean, slag free, flame cut bevel is acceptable.
Tack welds with full penetration shall be used and shall become the part of the finished weld.
Defective welds or tack welds with lack of penetration are not acceptable and shall be chipped /
ground out. No temporary weld attachment shall be with extended clamps / attachments.
2.5 Other alignment considerations
All flange facing shall be true and perpendicular to the axis of the pipe to which they are attached.
Flange bolt holes shall straddle the normal centre
Lines unless different orientation is shown in drawings to match the equipment connections
etc.tolerances on fabrication shall be as per standard.
2.6 Mitre Bends & Fabricated Reducer
The specific application of welded mitre bends and fabricated reducers shall be governed by the
piping material specifications to be furnished to the contractor. The angle of the each cut
segment shall be 15deg, 30deg, 30deg and 60deg for right angle bends (4 piece mitres).
The piping rates shall be inclusive of erection of mitre bends and fabrication of reducers.
However, the contractor shall be paid separately for fabrication of bends where required.
2.7 Pipe joints
The relevant piping class attached to each line specifies the type of pipe joints to be adopted in
construction in all piping systems. In general, joining for lines 2” and above in utility piping
system shall be accomplished by butt welding connections. Pipe lines 1 ½” and below shall have
socket welded / butt welded / screwed joints as specified in the piping materials specifications.
Butt welded joints shall be as per standard.
In general, flanged connections shall be used at connections to all equipment and where required
for ease of erection and maintenance purposes.
2.8 Cleaning of piping
On completion of fabrication, all pipes and fittings shall be cleaned inside and outside by suitable
means (Mechanical cleaning tool, wire brush, etc.) before erection to ensure that assembly is free
from all loose foreign material such as scale, sand, weld, spatter particles, cutting chips, etc.

All field fabricated piping shall also be cleaned at the completion of the fabrication. All burrs,
welding circles and weld spatter shall be removed by any suitable means (mechanical tools, wire
brush etc.)
Both shop and field fabricated piping shall be blown out with compressed air at the termination of
cleaning and capped.
Cleaning requirements for special services, if any, shall be as specified in the piping material
specifications.
Performances of welds and heat treatment
All welding and heat treatment shall be performed in accordance with the welding specifications
detailed elsewhere.
3. ERECTION
3.1 The intent of pre-fabrication at the shop is to accelerate progress of pipe work and to minimize
working the field. Such pre-fabrication should be based on approved isometric and piping
layouts furnished to the contractor. Field weld is indicated by FW on isometrics. Field weld
means position weld of prefabricated piece at site or near the plant. However the contractor shall
bear in mid that there can be variations in dimensions between those appearing in the isometrics /
layouts and those actually occurring at the site due to minor variations in the location of
equipment, inserts, etc. The contractor shall, therefore, provide adequate field joints, if required,
other than shown in isometric and fit-in sections permitting the pre-assembly to be installed
without any modification. In any case no extra clamps will be entertained on this account.
All piping shall be routed and located as shown in piping drawings keeping in view the piping
specifications. No deviations from the arrangement shown shall be permitted without the
express consent of the Engineer in charge.
a) While fitting up mating flanges, care shall be exercised to properly align the pipes and to check
the flanges for trueness, so that faces of the flanges can be pulled up together without inducing
any stresses at the pipes and equipment nozzles. The bolt holes of flanges in the vertical plane
shall straddle the vertical centre line of the pipe in the erected position and for flanges in the
horizontal plane, the bolt holes shall straddle horizontal plane unless otherwise indicated on the
drawings
b) Flanged connections at the pump, turbines, compressors shall be made in such a way as
not to induce any stresses due to mis-alignment, excessive gap etc. The final tightening shall be
redone when the machines are aligned completely and specifically authorized by the Engineer in
charge. Temporary protective covers shall be provided at all flanged connections of pumps,
compressors, turbines and other similar equipment until the piping is finally connected.
Slopes specified for various lines in the drawings shall be maintained by the contractor. In case
the contractor s unable to maintain the indicated slope he shall check the sagging of the pipe with
a precision spirit level. Vents and drains are shown in the isometric of each line and these are
intended, during hydrostatic test, for releasing the trapped air and draining out the test fluid after
testing. Valved vents and drains are also shown wherever required. The contractor shall provide
vents and drains connections even when these are not shown in the drawings and are found

necessary by the Engineer in charge for process lines. The details for the type of connections to
be adopted shall be given to the contractor at the time of work.
After the piping is erected in final position, it shall be cleaned, tested for tightness and kept dry
wherever instructed, as described in this specification.
Valves
The valve spindle positions are shown in the arrangement drawings and the contractor shall be
required to follow them. He shall, however, bring it to the notice of the Engineer in charge in
case he encounters some difficulty in installing them.
Where practicable and except when otherwise shown on the drawings, valve stems shall be
installed in a vertical direction and shall not be installed with stems below the horizontal axis.
Supports
Supports, guides and anchors for piping shall be fabricated and provided as shown in the
drawings. No anchors on piping shall be used except at locations shown in the drawings. The
pipe shall be secured firmly at anchor supports.
Fabrication and erection of supporting elements and structural fixtures wherever required and
pointed out by the Engineer in charge, whether indicated in drawing or not, to prevent vibration,
excess sag etc. shall be carried out by the contractor. No separate payment will be made for
erecting of these additional supports and it will be deemed as part of piping erection work.
4. LAYING OF UNDERGROUND PIPING
The Contractor shall lay the underground piping in accordance with the following clauses and as
per the piping arrangement drawings/stetches issued during the course of construction. Coating
and wrapping of the underground lines shall be in accordance with specification.
The contractor shall dig the pipe line trenches where necessary according to the drawing, true to
the line and gradient as per specifications and as directed by the Engineer-in-charge.
The contractor shall be responsible for correct layout and gradient of the line. Errors, if any, shall
be rectified by the Contractor at his own cost.
Trenching: (Refer specification for Earthwork in underground piping)
The trench shall be cut true to the line leveled with the help of sight rails provided at every 30 M at
change of direction, gradient and at any suitable distance as directed by Engineer in charge.
If the trench is excavated below the required level indicated in the drawing, the extra depth shall
be filled with concrete or approved equivalent material as directed by the Engineer in charge at
no extra cost to owner.
The trench shall be excavated so as to provide an average cover of 1000 mm or equal to the
diameter of the largest pipe to be laid in the trench, or as shown in drawings whichever is greater.
The average cover will be reckoned from top of the pipe of the largest diameter to be laid in the
trench, to the finished grade. The width of the trench shall be sufficient to give free working

space on each side of the pipe. The free working space shall conform to IS: 783. Generally it
shall not be less than 150 mm on either side or 1/3 of dia of pipe whichever is greater.
No excavated material shall be deposited within 1.5 metres from the excavated trench.
In case of road cutting, all material, i.e. metal, bricks etc. shall be taken out carefully and kept
separately for reuse and road work shall be redone upto the original level prior to cutting the road
with the excavated road materials after laying and testing of the pipe line within 10 days from the
date of starting the work at the cost of the contractor. The contractor shall provide suitable sings
and barricades to prevent accidents. He shall also provide reasonable by pas at his own cost
when a road is cut for laying pipeline.
During excavation, if some obstacle is met with, the same shall be reported to the Engineer in
charge and dealt with as instructed by him.
The contractor shall dewater, shore or do whatever might be required to excavate the trench, install
the pipe in it and backfill the trench, in accordance with the specifications at no extra cost to the
owner. Dewatering shall be done in advance of the laying of the pipe to allow adequate
inspection of padding of the bottom if required and dewatering shall be continued throughout
during laying of the pipe an backfilling of the trench.
In muddy slushy ground, the bed shall be provided with a layer of a sand or lean concrete as
directed by the Engineer in charge.
The trench shall follow the gradient of pipeline as specified in the drawing. The contractor shall
keep the trench in good condition. Until the pipe is laid and tested, no extra claim shall be
entertained due to its caving or setting down either before or after the pipe is laid. All materials
to shore the trench in order to prevent caving are to be furnished and removed by the Contractor
at no extra cost to the owner.
In case pipe is lowered in caved trench and back filled before being inspected by the Engineer in
charge, the contractor shall re-excavate the trench, for inspection and backfill it at his own cost.
5.0 Lowering and laying
The pipe shall be lowered either by mechanical method or by hand when the trench is ready and
bottom of the trench is graded as per required pipe laying conditions and specifications.
5.1 By Machine
The shop coated pipe, already transported to the pipe laying site / convenient length of pip
assembly coated and wrapped near the trench after hydrostatic testing shall be placed on clean
square cut skids suitably spaced so as to keep the pipe way from touching the ground. The pipe
may be lowered down in the trench by the launcher cranes, with sufficient care to protect the
coating and wrapping of the pipelines.
At tie in welds and other places, the contractor shall clean, prime, coat and wrap manually. Also
short sections of pipelines which are impracticable to shop treat may be hand treated but only on
the prior written approval of the Engineer in charge.

5.2 By Hand
The pipe may be lowered with the help of tripods and chain pulley blocks into the trench
immediately after the coating and wrapping. However, if in the opinion of the Engineer in
charge that the temperature conditions do not allow direct lowering, then the pipes shall be set
down on clear square cut skids. The skids shall be so spaced as to keep the pipe away from
touching the ground.
Method & Time of Lowering Pipe
Under favourable temperature, conditions and using methods which will not damage coating, the
pipe may be lowered into the trench.
Pipe previously set on skids, because of un-favourable temperature conditions shall be lowered
into the trench normally in the cool of the morning and only when the temperature of the pipe is
below the softening point of the coating materials.
All skid marks and other places of damage shall be thoroughly examined to ensure proper patching
where necessary, before the pipe is finally lowered into the trench.
6.0 Handling coated pipe
Coated pipe shall not be placed in trench until cave in plugs, hard clods; stones, skids, welding
rods etc. have been removed there from. Where the trench has a hard or jagged bottom,
sufficient fine dirt or sand shall be placed therein, before the pipe is lowered.
Coated pipe shall not be handled or moved by means of cable or chains or by praying with skids
or bars, it shall be tightened and lowered by using lowering in belts of a standard width and
design for the size of pipe being handled.
Coated pipe shall not be dragged along the ground or otherwise handled in a manner that will be
detrimental to the coating.
Lining up and welding
The ends of the pipe line shall be kept securely closed to prevent entry of any foreign material /
moisture after lowering into the trench.
Before making joint, the pipe shall be carefully laid so as to be perfectly aligned in both plan and
profile, and the end closure provided shall be removed. Tie in shall be made in the coolness of
the morning or when the ambient temperature is not exceeding 29 deg C or softening
temperature of the coating material whichever is less. All beveling aligning and welding shall be
in accordance with the welding specification given in the tender.
Free access shall be provided for the welding of the circumferential joints by increasing the width
and depth of the trench at these points. There should be no construction to the welder from any
side so that good welded joint is obtained.
Testing & coating wrapping

The completed system shall then be tested as per clause 6 and the field welded joints coated and
wrapped as per specification.
7.0 Back Filling
After testing and inspection of the pipeline to the entire satisfaction of the Engineer in charge, the
trench shall be back filled with the excavated material. No trench shall be back filled without the
approval of the Engineer in charge. Backfilling with the excavated material shall be done in
layers of 200 mm well watered and rammed to avoid any settling afterwards.
The contractor shall place soil over the trench to such a height as well as in opinion of the Engineer
in charge, to provide adequately for future settlement of the trench backfill.
If due to exigencies of the work, some portion of the pipeline is backfilled without approval of the
Engineer in charge, the engineer in charge shall have the right to order uncovering of the pipe for
examination and the cost of such uncovering shall be borne by the Contractor.
The backfill material shall free from stone pieces.
Surplus excavated soil or rubbish material shall be removed by the Contractor at his own cost to a
place designated by the Engineer in charge.
When the trench has been dug through roads, all backfill shall be thoroughly compacted. In
certain cases, special compaction methods may be required by the Engineer I charge. This shall
be done by the contractor at no extra cost to the owner.
When the trench has been dug through unlined ditches the backfill shall be thoroughly compacted
in 150 mm layers for a distance of 1.50 m beyond the outside banks of the ditch on either side.
The banks of the ditch shall also be compacted in 150 mm layers at no extra cost to the owner.
After the roads have been already graded and if they are trenched or otherwise disturbed by the
Contractor during laying of the pipe lines, the contractor shall restore the road to its original level
and condition. In the event, the contractor is required to place extra fill, gravel, or other special
materials it shall be done by him without any extra cost to the owner.
Clean up of surroundings
As soon as the backfill is completed, the contractor shall immediately clean up the adjoining area
by removing all surplus and defective material and dispose of all refuse such as spurs, sheet-iron,
broken skids, etc. to the complete satisfaction of the Engineer in charge.
The earth on both sides of the pipeline trench which has been disturbed during the construction of
the pipe line shall be smoothened and left in a condition satisfactory to the Engineer in charge.
8.0 INSPECTION
General
Owner’s inspector shall have free access to all places where the work is being done or any other
thing and place concerned with the work.

Owner is entitled to send his own inspector, to field or shops where pre-fabrication and erection of
pipe lines are being done, with the following functions but not limited to :
i) To check that the welding performance and welding equipments used on the job are suitable and
conform to relevant standards.
ii) To supervise welding procedure qualification.
iii) To supervise welder performance qualification.
iv) To check whether welding is conforming to relevant specification and the practice
construction practice.
To check any other performance to ensure quality of work.
Contractor shall notify sufficiently in advance the commencement of qualification tests, welding
work and acceptance tests, to enable the Owner’s Inspector to supervise the same.
Contractor shall provide the Owner’s Inspector with all facilities necessary for carrying out his
work at no extra cot to the owner.
Approval from the Owner’s Inspector shall not relieve the contractor partially or fully of his
responsibilities and guarantees under this contract.
Visual Inspection
Inspection of all welds shall be carried out as per ANSI B 31.3. Finished welds shall be visually
inspected for parallel and axial misalignment of the work, cracks, inadequate penetration, un
repaired burn-through, dimensions, and other surface defects, and it shall present a neat workman
like appearance. Under cutting adjacent to the final bead on the outside of the pipe shall not
exceed 0.8 mm in depth of 12 ½% of the pipe wall thickness, which ever is smaller and the
cumulative length shall not be more than 50 mm in any continuous 300 mm length of weld.
Repairs or removal of defects
Defects which are not within the acceptable limits shall be removed from the joint completely by
chipping or grinding.
When the whole joint is found unacceptable, the weld and the ends of the joints shall be restored
according to relevant clauses under fabrication.
No repair shall be carried out without prior authorization of the Engineer in charge.
9.0 TESTING
General
The field test pressure shall not be less than the greatest of the following:
a) 1 ½ times the maximum sustained operating pressure.
b) 1 ½ times the maximum pipeline static pressure and
Sum of the maximum sustained operating pressure or the maximum pipe line static pressure and
the maximum calculated surge pressure.

The field test pressure shall wherever possible be not less than two thirds of the works test
pressure and shall be applied and maintained for at least four hours.
Where the field test pressure is less than two thirds the works test pressure, the period of test shall
be increased to at least 24 hours. The test pressure shall be gradually raised at the rate of nearly
kg / cm 2 / minute.
All underground / above ground pipes shall be tested for leakages to a minimum hydrostatic test
pressure of 10 kg/ cm2 gauge.
The testing shall be carried out in convenient section as approved by the Engineer in charge. The
joints of the pipe connecting the testing sections shall be 100% radiographed.
If some defect is noticed during the hydrostatic testing, the same shall be brought to the Notice of
Engineer in charge. Joints, if leaking, shall be rectified as per the welding specifications and
instructions of engineer in charge and tested to his satisfaction at no extra cost to the owner.
The engineer in charge shall be notified in advance by contractor of all testing. The hydrostatic
testing / flushing of all the piping shall be carried out by the contractor at his own cost.
Contractor shall make his own arrangements for flushing at suitable points as per the instructions
of the Engineer in charge. Any extra work / modification on this account shall be done by the
contractor at his own cost.
Test medium
Construction water shall generally be used as the testing medium for the hydrostic testing of
piping system.
Cleaning
All systems shall be cleaned and flushed free of all dirt, debris or loose foreign material after
testing.
Temporary Blinds
Open ends of piping systems such as a pumps or wherever equivalent has been removed or
disconnected prior to hydrostatic testing, or at termination point of piping branch connections
shall be blinded of by temporary blind flange made out of 10 mm thick M.S. plate.
Venting:
All piping systems and equipments shall be properly vented to remove air from system during
filling.
Pressurizing
Pressure shall be applied by means of a suitable test pump which shall not be connected to the
system until ready to test. A pressure gauge shall be provided at the pump discharge for
guidance in bringing the system upto pressure. The pump shall be attended to constantly during
the test by an authorized operator. The pump shall be disconnected after the pressure test is
completed.

The test pressure is to be maintained for sufficient time to permit complete inspection of the
system under test but in no case shall the time be less than ten minutes. Test shall be considered
complete only when approval is given by the Engineer in charge.
Test Gauges:
Draining
Contractor’s own test gauge shall be installed as close as possible to the lowest point in the system
being tested. Prior to installation, the test gauge shall be checked against a standard gauge or
calibrated with the aid of a dead weight tester. Calibration of test gauges shall be the
responsibility of the contractor.
All lines and equipments shall be completely drained after the hydrostatic test of a system has
been completed. High point vents shall be open to prevent excessive vacuum and permit
complete draining.If it becomes necessary to leave a system filled with the testing medium for
any abnormal length of time, such as venting shall be made to provide for possible liquid
expansion with change in ambient temperatures.
10.0 RECORDS
Records in triplicate shall be made for each piping system as follows:
10.1 In case of underground piping, layouts giving actual elevations or pipeline as laid.
10.2 Test certificates containing date or test, identification of the piping system, test fluid used, test
pressure and approval of owner’s inspector.
Certificates for flushing containing flushing medium used, identification of the piping system, date
of flushing and approval by owner’s inspector.
PAYMENT
Payment for piping shall be based on linear measurements calculated on the basis of the execution
drawings. The length shall be measured along the centre lines of pipes, centre lines of bends and
elbows, tees, reducer, SW, flanged joints. All types of valves shall be excluded from this
measurement. Branch connections shall be measured from the outer surface of the header.
The payment shall be made on per metre basis of piping work erected, measured to the nearest
centimeter.
The unit rates for the underground piping shall be inclusive of earthwork excavation, backfilling,
and compaction, disposal of surplus earth, coating and wrapping including supply of materials.
The unit rates for above ground carbon steel piping shall be exclusive of erection of all types of
supports but inclusive of supply of necessary bolts nuts and washers gaskets etc as per respective
specification.
Payment for the installation of sluice valves, check valves, butterfly valves, expansion bellows
will be made on number basis and the unit rates shall be inclusive of supply of necessary bolts
nuts, washers and gaskets, etc.

All piping attachments, such as coupling, nipples, thermo wells etc. shall be installed by the
Contractor as per the piping work and no separate payment shall be made for such work.
However, extension on such attachments such as vents and drains will be measured and paid as
applicable for the respective size and category of piping / valves.
Fabrication of mitre bend, concentric and eccentric reducers fabricated from pipes supplied by
owner, and fabrication of flanges from plates supplied by owner, will be paid at respective unit
rates. However, erection of these items will be along with piping of the respective size and no
separate payment will be made for erection. The reducers will be measured and paid along with
the piping of large diameter.
No separate payment will be made for making pipe to pipe branch connection crosses with or
without reinforcing pads and the unit rates for piping are deemed to include all such work.
Fabrication, installation and removal of temporary spool pieces etc. to aid contractor’s work such
as fabrication, erection, flushing testing, and etc. will neither be measured nor paid separately.
The same is deemed to be included in the unit rates for piping.
Payment for carrying out radiographic examination shall be based on linear length of the welded
joint radiographed. Repeat radiography / additional radiography required due to contractor’s
fault / poor performance of his welders, defective films shall be done at contractor’s own cost.
WELDING SPECIFICATION FOR THE FABRICATION OF PIPING
(Above Ground Portion)
1. GENERAL
This specification shall be followed for the fabrication of all types of welded joints of
carbon steel and alloy steel piping system within the battery limits of the plant.
The welded pipe joints shall include the following:
a) All pipe joints of the longitudinal and circumferential butt welded and socket welded
types.
b) Attachments of forgings, flanges and other supports to pipes.
c) Welded manifold headers and other sub-assemblies
d) Welded branch connections with or without reinforcing pads.
e) Joints in welded / fabricated piping components.
f) The attachments of smaller connections for vents, drain drips and other instrument
tappings.
Any approval granted by the Engineer-in-charge or Owner's inspector, shall not relieve the
Contractor of his responsibilities and guarantee.
This specification shall not be applicable for welding of pipelines for transportation of liquid
petroleum and other similar products.
2. APPLICATION CODES &STANDARDS :
All welding work, equipments for welding, heat treatment, other auxiliary functions and the
welding personnel shall meet the requirements of the latest editions of the following expected
standards and procedures unless otherwise specified in the Welding specification chart and

the technical notes attached. In the case of conflicting requirements, the requirements
mentioned in welding specification chart / Technical Notes shall be applicable.
a) Chemical Plant and Petroleum Refinery Piping - ANSI:B31.3
b) The Indian Boiler Regulations - I.B.R.
relevant code of fabrication shall be followed for the welding procedures.
i. Welding and Brazing Qualifications ASME Sec IX.
ii. Non destructive examination ASME Sec. V
iii. Material Specifications : welding rods, Electrodes and filler metals ASME Sec II Part
C
In the event of any differences due to the additional requirements mentioned in this specification, over
and above those obligatory as per codes, this specification shall be binding.
3. BASE METAL:
3.1 In general, use of carbon steel, alloy steel and stainless steel are envisaged. The details of
the material specifications are given in the welding specification chart.
3.2 The contractor shall provide the manufacturer's test certificates for every heat of the
materials supplied by him.
4. WELDING CONSUMABLES
4.1 The contractor shall provide, at his own expense, all the welding consumables necessary for
the execution of the job such as electrodes, filler wires, oxygen, acetylene, argon etc, and
these should bear the approval of the Engineer-in-charge.
4.2 The welding electrodes and filler wires supplied by the Contractor shall conform to the class
specified in the welding specifications chart. The materials shall be of the make approved
by the Engineer-in-charge.
4.3 Electrode qualification test records should be submitted as per the Exhibit –A (attached) in
respect of the electrodes tested by the Contractor, for obtaining the approval of the engineerin-charge.
4.4 The contractor shall submit batch test certificates, from the electrode manufacturers, giving
details of physical and chemical tests carried out by them, for each batch of electrode to be
used.
4.5 All electrodes shall be purchased in sealed containers and stores properly to prevent
deterioration. The electrodes removed from the containers shall be kept in holding ovens at
temperatures recommended by the electrode manufacturer. 'Out of the oven time' on
electrodes, before they are consumed shall not exceed the limits recommended by the
electrode manufacturer. The electrodes shall be handled with care to avoid any damage to
the flux covering.
4.6 All low hydrogen tupe of electrodes shall be rebarked at 350 0 C for 1 hour minimum and
stored in ovens kept at 80-100 0 C before use. Recommendations of the electrode
manufacturer shall be followed if available.
4.7 The electrodes, filler wires and flux used shall be free from rust, oil, grease, earth and other
foreign matter which affect the quality of welding.
4.8 Tungsten electrodes used shall conform to SPA 5.12 specification.

5. SHIELDING & PURGING GAS :
5.1 Argon gas used in GTA welding for shielding purpose shall be 99.995% pure. The purity of
the gas shall be certified by the manufacturer. The rate of flow shielding purpose shall be
established through procedure qualification tests. Normally this rate may be 12-20 CFH.
5.2 Argon gas with a purity level of 99.995% shall be used for purging.
5.3 When GTAW process alone or a combination of GTAW processes is recommended for the
production of a particular joint, the purging shall be maintained during the root pass and for
the first filling pass to minimize oxidation on the inner side of the pipe, unless otherwise
specified in welding specification chart.
5.4 Initial purging shall be maintained for sufficient period of time so that at least 4-5 time the
volume between the dams is displaced, in order to completely remove the entrapped air. In
no case should the initial purging period be less than 10 minutes. High gas pressure should
be avoided.
5.5 After initial purging, the flow of the backing gas should be reduced to a point where only a
slight positive pressure prevails. For systems which have a small volume ( upto ½ cubic
foot) to be purged, a gas flow rate of 6-CFH is usually adequate. Systems of larger volume
may require higher flow rates and these should be established procedure qualification tests.
5.6 Gas backing (purging) is not required for socket type of welded joints.
5.7 Dams, used for conserving inert gas during purging, shall be removed after completion of
the welding, and shall be accounted for. Wherever, removal of dams is not possible after
welding, use of water soluble dams should be made.
2. EQUIPMENTS & ACCESSORIES :
6.1 The contractor should have the arrangement of sufficient number of welding and cutting
equipments, auxiliaries, and accessories of sufficient capacities so as to meet the target/
schedule.
6.2 All the equipments for performing the heat treatment, including transformers, thermocouples,
pyro-meters, automatic temperature recorders with suitable calibration
arrangements etc. shall be provided by the Contractor at his own expense and these should
bear the approval of the Engineer-in-charge.
6.3 Contractor shall make necessary arrangements at his own expense for providing the
radiographic equipments, radiographic films, and all the equipments / materials required for
carrying out the dye-penetrant/ magnetic particle test for satisfactory and time completion of
the job.
6.4 Redoing of any work necessitated by faulty equipments or operaion used by the Contractor,
will be done at his own expense.
3. WELDING PROCESSES :
7.1 Welding of various materials under this specification shall be carried out using one or more
of the following processes with the approval of the Engineer-in-charge.
- Shielded Metal Arc Welding Process (SMAW)
- Gas Tungsten Arc Welding Process (GTAW).
7.2 The welding processes to be employed are given in the welding specifications chart. Any
deviation desired by the contractor shall be obtained through the express consent of the
Engineer-in-charge.

7.3 Automatic and semi-automatic welding processes shall be employed only with the express
approval of the Engineer-in-charge. The welding procedure adopted and consumables used
shall be specifically approved.
7.4 A combination of different welding processes could be employed for a particular joint only
after duly qualifying the welding procedure to be adopted and obtaining the approval of
Engineer-in-charge.
4. EDGE PREPARATION :
8.1 The edges to be welded shall be prepared to meet the joint design requirements by any of
the following methods recommended.
a. Carbon Steel
Gas cutting, machining or grinding methods shall be used. After gas cutting, oxides
shall be removed by chipping or grinding.
b. Low Alloy Steels (containing upto 2 ½ chromium):
Gas cutting, machining or grinding methods shall be used. After cutting, machining or
grinding shall be carried out on the cut surface.
c. High alloy steels, cupro-nickel, nickel alloys, and aluminium alloys:
Plasma cutting, machining or grinding methods shall be used. After plasma
cutting, cut surfaces shall be machined or ground smooth.
8.2 Cleaning-
a. The ends to be welded shall be properly cleaned to remove paint, oil, grease, rust, oxides,
sand, earth and other foreign matter. The ends shall be complete dry before the welding
commences.
b. On completion of each run, craters, welding irregularities, slag etc., shall be removed by
grinding and chiseling. Wire brushes used for cleaning stainless steel joints shall have
stainless steel wires and the grinding wheels used for grinding stainless steel shall be of
suitable type. Separate grinding wheels and wire brushes should be used for carbon steels
and stainless steel.
9. ALIGNMENT & SPACING :
9.1 Components to be welded shall be aligned and spaced as per the requirements laid down
in applicable code. Special care must be taken to ensure proper fitting and alignment
when the welding is performed by GTAW process. Flame heating for adjustment and
correction of end is not permitted unless specifically approved by the engineer-in-charge.
9.2 A wire spacer of suitable diameter may be used for maintaining the weld root opening
while tacking, but it must be removed after tack welding and before laying the root bead.
9.3 For pipes of wall thickness 5mm and above, the ends to be welded shall be secured in
position with the aid of couplers; yokes and 'C' clamp to maintain perfect alignment.
Yokes shall be detached after the completion of weld, without causing any surface
irregularity. Any irregularity caused on the pipe surface must be suitably repaired to
satisfaction of the engineer-in-charge.
9.4 Tack welds, for maintaining the alignment, of pipe joints shall be executed carefully and
shall be free from defects. Defective tack welds must be removed prior to the actual
welding of the joints.
9.5 Tacks should be equally spaced. Minimum number of tacks shall be
2 tacks – for 2 ½ '' and smaller dia pipes
4 tacks - for 3" to 12'' dia. pipes
6'' tacks – for 14'' and larger dia pipes

9.6 Engineer-in-charge shall check and approve the fit-up and alignment pipe joint prior to the
commencement of welding.
10. WEATHER CONDITIONS :
10.1 The parts being welded and the welding personnel should be adequately protected from
rain and strong wings. In the absence of such a protection no welding shall be carried out.
10.2 During field welding using GTAW process, particular care shall be exercised to prevent
any air current affecting the welding process.
11. WELDING TECHNIQUE :
11.1 Root Pass
a) Root pass shall be made with electrodes/ filler wires recommended in the welding
specification chart. For fillet welding root welding shall be done with consumables
recommended for filler passes. The preferable size of the electrodes is 2.5 mm diameter
(12 SWG) but in any case not greater than 3.25 mm (10 SWG)
b) Upward technique shall be adopted for welding pipe held fixed with its axis horizontal.
c) The root pass of butt joints should be executed so as to achieve full penetration with
complete fusion of the root edges. Weld projection inside the pipe shall not exceed 3
mm, wherever, ___ specified by the applicable code.
d) Any deviation desired from the recommended welding technique and electrodes indicated
in the welding specification chart should be adopted only after obtaining express approval
of the Engineer-in-charge.
e) Welding shall be uninterrupted.
f) While the welding is in progress care should be taken to avoid any klind of movement of
the components, shocks, vibrations and stresses to prevent occurrence of weld cracks.
g) Peening shall not be used
11.2 Joint Completion
a) Joint shall be completed using the class of electrodes, recommended in the Welding
Specification Chart. Size of the electrode shall not exceed 4 mm in diameter for stainless
steel and alloy steels used for low temperature applications.
b) Two welds beads shall not be started at the same point in.
c) Butt joints shall be completed with a cover layer that would affect good fusion at the joint
edges and a gradual notch free surface.
d) Each weld joint should have a workman like finish.
e) Weld identification work shall be stamped clearly at each joint just adjacent to the weld.
Metal stamping shall not be used as standard. Suitable paint shall be used on thin wall pipes
for identification.
f) No painting shall be done until the weld joint has been approved.
11.3 Dissimilar welds
Where welds are to be produced between carbon steels and alloy steels, preheat and postweld
Heat Treatment requirement shall be those specified for corresponding alloy steels and electrodes
shall correspond to AWS E-7016/7018 type. For welds between two dissimilar Cr-Mo low alloy
steels, preheat and post weld heat treatment shall be those specified for higher alloy steel and
electrodes used shall correspond to those specified for steel of lower alloy content. For carbon
steel or alloy steel to stainless welds, use of electrodes E-309 / E-310/ E NiCr Fe-2 shall be
made. The welding procedure, electrodes/ filler wires to be used, approved by the Engineer-incharge.

12. HEAT TREATMENT :
12.1 Preheating
a) No welding shall be performed without preheating the joint to 10º (50ºF) when the ambient
temperature is 10º and below.
b) Preheating requirements for the various materials shall be as per the welding specification
chart attaches.
c) Preheating shall be performed using resistance or induction heating methods. Preheating by
gas burners, utilizing oxy-acetylene or oxy-propane gas mixtures, with neutral flame may
also be carried when permitted by the Engineer-in-charge.
d) Preheating shall extend ununiformly to at least three times the thickness of the joint, but not
less than 50 mm, on both sides of the weld.
e) Preheating temperature shall be maintained over the whole length of the joint during
welding. Temperature indicating caryons of other temperature indicating devices shall be
provided by the contractor to check the temperature.
12.2 Post Heating
In case of alloy steel materials such as Cr-Mc steels, if the Post We Heat Temperature is not
performed immediately after welding, the weld joint and adjacent of pipe, at least 150mm on
either side of weld, shall be uniformly heated to 300ºC. This temperature shall be maintained for
2 hours minimum, then wrapped in asbestos or insulating before allowing it to cool to room
temperature, postweld Heat Treatment as specified in the Welding Specification Chart shall be
carried out later on.
12.3 Postweld Heat Treatment
a) Post weld Heat Treatment, wherever required for joints between pipes, pipes and fittings,
pipe body and supports shall be carried out as per the welding specification chart, applicable
codes standards and the instructions of the Engineer-in-charge.
b) The contractor shall submit for the approval of the Engineer-in-charge, well before carrying
out actual Heat Treatment, the details of the post weld Heat Treatment procedure as per
Exhib B attached, that he proposes to adopt for each of the material assembly/ part involved.
c) Post weld Heat Treatment shall be done ina furnace or by using and electric resistance or
induction heating equipment, as decided by the Engineer-in-charge.
d) While carrying out local post weld Heat Treatment, technique of application of heat must
ensure uniform temperature attainment at all points of the portion being heat treated. Care
shall be taken to ensure that width of heated band over which specified post weld Heat
Treatment temperature attained is at least that specified in the relevant applicable
standards/codes.
e) Throughout the cycle of heat treatment, the portion outside the heated band shall be suitably
wrapped under insulation so as to avoid any harmful temperature gradient at the exposed
surface of pipe. For this purpose temperature at the exposed surface of pipe should not be
allowed to exceed 400ºC.
f) The temperature attained by the portion under heat treatment shall be recorded by means of
thermocouple pyrometers. Adequate number of thermocouples should be attached to the
pipe directly at equally spaced locations along the periphery of the pipe joint. The minimum
number of thermocouples attached per joint shall be 1 upto 6'' dia, 2 upto 10'' dia and 3 for
12'' dia and above. However, the Engineer-in-charge can increase the required minimum
number of thermocouples to be attached if found necessary.

g) Automatic temperature recorders which have been suitably calibrated should be employed.
The calibration chart of each record should be submitted to the Engineer-in-charge prior to
starting the Heat Treatment operations and his approval should be obtained.
h) Immediately on completion of the Heat Treatment, the post weld Heat Treatment
charts/records along with the hardness test resulted on the weld joints, wherever required as
per the Welding Specification chart, shall be submitted to Engineer-in-charge for his
approval.
i) Each joint shall bear an identification number which shall be maintained in the piping sketch
to be prepared by the Contractor. The joint identification number should appear on the
corresponding post weld Heat Treatment charts. The chart containing the identification
numbers and piping sketch shall be submitted to the Engineer-in-charge in suitable folders.
13. CLEANING OF THE WELD JOINT
All weld joints shall be free from adherent weld spatters slag, swarf, dirt or foreign matter. This can
be achieved by brushing. For stainless steel, brushes with only stainless steel bristles should be
used.
14. INSPECTION AND TESTING
14.1 General
a) The owner's inspector shall have free access to all concerned areas, where the actual
work is being performed. The contractor shall also afford the Owner's Inspector all
means and facilities necessary to carry out inspection.
b) The owner is entitled to depute his own inspector to the shop or field where
prefabrication and erection of pipe lines are being done with (but not limited to) the
following objectives.
i. To check the conformance to relevant standards and suitability of various
welding equipments and the welding performance.
ii. To witness the welding procedure qualification
iii. To witness the welder performance qualification
iv. To check whether shop/field welding being executed is in conformity with the
relevant specifications and codes of practice followed in piping construction.
c) Contractor shall intimate sufficiently in advance the commencement of qualification
tests, welding works and acceptance tests to enable the Owner's inspector to be
present to supervise them.
14.2 Welding Procedure Qualification
Welding procedure qualification shall be carried out in accordance with the relevant
requirement of ASME Sec. IX latest edition or other applicable codes and the job
requirements. The contractor shall submit the latest welding procedure specifications in
format as per Exhibit-C (attached) immediately after the receipt of the order.
by the owner's Inspector shall be employed for welding. Contractor shall submit the
welder qualification test report in the format as per Owner's inspector will review, check
and approve the welding procedure submitted for his approval immediately after
completing the procedure qualification test and at least 2 weeks before the
commencement of actual work. Standard tests as specified in the code shall be carried

out in all cases. In addition to these tests, other tests like macro/micro examination,
hardness tests, dye penetrant examination, charpy V-notch and U-notch impact test etc
shall be carried out on specimens depending upon the ytpe of base matter operating
conditions and requirements laid down in the detailed drawings and specifications. It
shall be the responsibility of the Contractor to carry out all the tests required to the
satisfaction of the Owner's inspector.
and shall release the procedure for qualification tests. The procedure qualification test
shall be carried out by the Contractor at his own expense. A complete set of test results
in format as per Exhibition attached shall be submitted to the owner's inspector
14.3 Welder's Qualificaton
a) Welders shall be qualified in accordance with the ASME Section –IX or
other applicable codes. The owner's inspector shall witness the test and
certify the qualification of each welder. Separately only those welders who
have been approved Exhibit –E (attached) and obtain express approval
before commencement of the work. It shall be the responsibility of
Contractor to carry out qualification tests of welders. For welding of the
only those welders with IBR Certifications, qualified by Boiler Inspectorate,
and acceptable to the local Boiler Inspector authority shall be employed.
b) The welders shall always have in their possession the identification card as
shown in Exhibit –G and shall produce it on demand by the Owner's inspector.
It shall be the responsibility of the Contractor to issue the identity cards after it
has been duly certified by the Inspector.
c) No welder shall be submitted to work without the possession of identity card.
d) If the welder is found to perform a type of welding in a position for which he
is not qualified, he shall be debarred from doing any further work. All welds
performed by an unqualified welder shall be cut and redone by a qualified
welder at the expense of the Contractor.
14.4 Visual Inspection
Inspection of all welds shall be carried out as per the latest editions of the applicable codes
and specifications. All finished welds shall be visually inspected for parallel and axial
alignment of the work, excessive reinforcement, concavity of welds, shrinkages cracks,
inadequate penetration, unrepaired burn-through, under cuts, dimentions of the weld,
surface porosity and other surface defects. Undercutting adjacement to the completed weld
shall not exceed the limits specified in the applicable standard/code.
14.5 Radiographic Examination
a) The Radiographic Examination procedure to be adopted shall be submitted by the
Contractor as per Exhibit-P and shall be got approved by the Owner's Inspector prior
to employment. The radiographic technique and procedure adopted shall conform to
the requirements mentioned in Article 2, as well Article (SE94, SE 142) of ASME Sec
V. The IQI sensitivity obtained shall be equal to or better than the requirements
mentioned in table 262.2 and table 272 of Article 2 of ASME Sec V for single wall
and double wall radiography respectively. Source side procedure/technique. The
acceptable limits of defects and removal of defects shall be as per the relevant codes of
fabrication. The contractor shall be responsible for carrying out Radiography,
rectification of defects and re-radiography of welds repaired/rectified.

) The extent of Radiography shall be as per specifications to be supplied to the
Contractor. For welds between dissimilar materials, the extent of Radiographic
Examination for the materials being welded. Wherever random Radiography is called
for in a particular piping class, the dissimilar materials weld joint shall essentially be
included.
c) Radiographic Examination shall be carried out using X-Radiation, Gamma ray sources
may be used in place of X-ray with the approval of the Owner's inspector.
d) The contractor shall fulfill all the statutory safety requirement while handling X-ray
and Gamma-ray equipments.
e) The joints for Radiography shall be selected by the Owner's Inspector and the
Radiography shall be performed in his presence. The contractor shall furnish all the
radiographs to the owner's Inspector immediately after processing. The details of the
radiographs along with the joint identification number shall be duly entered in a
register and signed by the Contractor and shall be submitted to the Owner's Inspector
for approval.
f) The contractor shall provide the Inspector all the necessary facilities at site such as a
dark room with controlled temperature, film viewer etc. to enable him to examine
the radiographs.
g) Where random radiography is specified, the first weld of each welder shall be
completely radiographed. In the case of pipe of sizes 6'' and below, the first two welds
shall be completely radiographed.
h) For each weld performed by a welder, found unacceptable two additional checks
should be carried out on welds performed by the same welder. This operation is
iterative and the procedure of radiographing two additional welds for each weld
deemed unsatisfactory shall be continued till such time that the two consecutive welds
of satisfactory are found for every defective weld.
14.6 Liquid Penetrant and Magnetic Particle Examination
a) Whenever such tests are specified, the tests shall be carried out on joints chosen by the
Owner's inspector, as per ASME Section V article 6 and 7 respectively.
b) For austentic stainless steels and other nonmagnetic materials, liquid (dye) penetrant
test shall be carried out. For carrying out this test, the materials shall be brought within
a temperature limit of 15º to 50ºC.
14.7 Hardness Test
Hardness required for welds shall be as per the welding specification chart (attached).
Hardness testing shall be carried out by Vickers Hardness Tester during welding procedure
qualification. In all other cases hardness testing may be carried out by Vickers, Brinnel, or
Poldy hardness tester as agreed by the Owner's Inspector.
14.8 Proof Tests
Hydrostatic and pneumatic tests shall be performed as per the requirement laid down by
respective flushing and Testing specification/applicable codes to demonstrate the
soundness of the welds. The tests shall be conducted after fulfilling the requirement of
visual examinations radiography etc., and after the entire work has been certified by the
Owner's inspector to be fit for being subjected to such tests.
15.0 REPAIRS OF WELDS
a) Defects ascertained, through the inspection methods, which are beyond acceptable limits shall
be removed after the joint is completely radiographed by the process of chipping and grinding.

) When the entire joint is judged unacceptable, the welding shall be completely cut and the edges
be suitably prepared as per required alignment tolerances. The rewelded joint shall again be
examined following standard practices.
c) No repair shall be carried out without prior permission of the Owner's inspector.
d) Repairs and / or work of defective welds shall be done in time to avoid difficulties in meeting
the construction schedules.
16.0 DOCUMENTS TO SUBMITTED BY CONTRACTOR (4 COPIES EACH)
a) Electrode and Welding Consumable Qualification Records as per Exhibit-A, for the Welding
Consumables tested and approved for the work.
b) Batch test Certificates, for the Electrodes used, obtained from the Electrode Manufacturer.
c) Proposed Heat Treatment Procedure as per Exhibit-B
d) Heat Treatment Charts
e) Weld joint hardness test results
f) Welding Procedure Specifications as per Exhibit-C immediately after receipt of the order.
g) Welding Procedure Qualification records as per Exhibit-D
h) Welder Performance Qualification records as per Exhibit-E immediately after conducting welder
qualification tests.
i) Radiography Procedure as per Exhibit-F
j) Radiographic test Report alongwith Radiographs.
Pipeline Sketch (Isometric) giving all the details regarding the pipe specifications, welded joints, joints
radiographed, joints heat treated, electrodes used, welders identification number etc