Cswip 3.2 spec converted

Document Number: TWI-WIS10 EX-MSR-001
Revision: 1
CSWIP 3.2 – Welding Inspector WIS10
Welding & Fabrication
Training Specification
Training & Examination Services
Granta Park, Great Abington
Cambridge CB21 6AL, UK
Copyright © TWI Ltd 2017

TWI WELDING & FABRICATION
TRAINING SPECIFICATION
Document Number: TWI-WIS10-EX-MSR-001 Revision: 3.5 Date: January 2017
Table of Contents
1.0 GENERAL. 8
1.1 Scope 8
1.2 Reference Codes and Standards 9
2.0 DEFINITION OF TERMS 10
2.1 General 10
2.2 Definitions 10
2.3 Table 1 - Abbreviations and Symbols 11
3.0 QUALITY CONTROL 12
3.1 Contractor Requirements 12
3.2 Fabrication Requirements 12
4.0 JOINT PREPARATION DETAILS 12
4.1 Base Metal Preparation 12
4.2 Bevels 12
4.3 Alignment 13
4.4 Assembly for Welding 13
4.5 Temporary Attachments 13
4.6 Weather Conditions 14
5.0 WELDING DETAILS 14
5.1 General Requirements 14
5.2 Butt Welds 14
5.3 Fillet Welds 14
5.4 Preheating 15
5.4.1 Table 2 – Preheat Values 15
5.4.2 Table 2a – Preheat Values 15

5.5 Interpass Temperature 16
5.6 Arc Strikes 16
5.7 Weld Identification 16
5.8 Interruption of Welding 16
5.9 Tack Welding 16
5.10 Inter-run Cleaning 17
6.0 WELDING ACCEPTANCE LEVELS 17
6.1 General 17
6.2 Excess weld metal 17
6.3 Root Profile 17
6.4 Cracks 17
6.5 Porosity and Cavities 17
6.6 Table 3 - Acceptance Criteria for Welds 18
7.0 WELDING EQUIPMENT 18
7.1 General 18
7.2 Welding and Cutting Equipment 18
7.3 Equipment for Measuring 18
8.0 WELDING CONSUMABLES 19
8.1 General 19
8.2 Storage and Handling 19
9.0 MATERIALS 19
9.1 General 19
9.2 Material Requirements 20
9.3 Material Marking 20
9.4 Material Storage and Handling 20
10.0 DEFECT REPAIR AND CUT-OUTS 20
10.1 General 20

10.2 Removal of Defects 20
10.3 Preparation for Re-Welding 21
10.4 Re-Welding 21
11.0 NON-DESTRUCTIVE TESTING 21
11.1 General 21
11.2 Equipment 21
11.3 Health and Safety Requirements 21
11.4 Documentation and Records 21
11.5 Magnetic Particle Inspection Details 22
11.5.1 General 22
11.5.2 Equipment and Consumables 22
11.5.3 Material Preparation 22
11.5.4 Techniques 22
11.6 Dye Penetrant Inspection Details 22
11.6.1 General 22
11.7 Ultrasonic Inspection Details 23
11.7.1 General 23
11.7.4 Scanning 24
11.8 Radiographic Inspection 25
11.8.1 General 25

11.8.3 Radiographic Sensitivity 25

12.0 INSPECTION PERSONNEL 26
12.1 General 26
12.2 Vision Requirements 26
13.0 RECORDS AND REPORTS 26
13.1 General 26
13.2 Frequency of Reports 26
14.0 SPECIFIC DETAILS FOR WELDING STAINLESS AND DUPLEX STAINLESS STEELS27
14.1 General 27
14.2 Material Details 27
14.3 Joint Preparation Details 27
14.4 Welding Details 27
14.5 Non Destructive Testing Requirements 28
15.0 SPECIFIC WELDING DETAILS FOR ALUMINIUM AND ALUMINUM ALLOYS 28
15.1 General 28
15.2 Material Details 28
15.3 Joint Preparation Details 28
15.4 Table 4 – Joint details for Aluminium Butt Welds 29
15.6 Table 5– Process 131 Heat Input Values 30
15.7 Table 5a – Process 141 Heat Input Values 30
16.0 SPECIFIC WELDING DETAILS FOR QUENCHED AND TEMPERED STEELS (QT Steels) 30
16.1 General 30
16.3 Table 6 – Minimum Preheat and Interpass Temperatures for QT Steels (A517 Grade) 31
16.4 Table 6a – Minimum Heat Input Values for QT Steels (A517 Grade) 31

17.0 QUALIFICATION OF WELDING PROCEDURES 31
17.1 General 31
17.3 Essential Variables 32
17.4 Table 7 - Changes Affecting Approval - Essential Variables 32
17.5 Welding of Test Joint 32
17.6 Extent of Testing 33
17.7 Table 8 - Examination and Testing of Test Pieces Non-Destructive Requirements 33
17.8 Table 8a - Examination and Testing of Test Pieces Destructive Test Requirements 33
17.9 Welding Positions 34
17.10 Joint Configuration 34
17.11 Location and Cutting of Test Specimens 34
17.12 Impact Testing (Charpy V-notch) 34
17.13 Table 9 - Impact Energy Values 34
17.14 Tensile Testing 34
17.15 Macro-Examination 35
17.16 Hardness Testing 35
17.17 Fillet Fracture Test 36
17.18 Bend Test 36
18.0 Qualification of Welders 36
18.1 General 36
18.3 Examination and Testing 36
18.4 Essential Variables and Range of Approval. 36
18.5 Table 10 – Essential Variables 37
18.6 Re Tests 38
18.7 Period of Validity 38

18.8 Welding Position Qualification Range. 38
18.9 Table 11 - Welding Position Qualification Range 39
18.10 Test to be Conducted 39
18.11 Table 12 - Welding Qualification Tests 39
19.0 Post Weld Heat Treatment (PWHT) 40
19.1 General 40
19.2 Temperature Measurement 40
19.3 Temperatures and Heating/Cooling Rates 40
19.4 Reports and Records 41
20.0 Hydrostatic Testing 41
20.1 General 41
20.2 Test Preparation 41
20.3 Flushing 41
20.4 Conducting the Test 41
20.5 Inspection 42
21.0 Pneumatic Testing 42
21.1 General 42
21.2 Test Preparation 43
21.3 Conducting the Test 43
21.4 Inspection 43
22.0 Coatings for Structures and Piping 44
22.1 General 44
22.2 Surface Preparation 44
22.3 Coating Application 44
22.4 Inspection 45

22.5 Repair of Damaged Areas (touch-up) 45
23.0 Protection and Preservation 46
23.1 General 46
GENERAL.
Scope
This document defines the technical requirements for the welding and fabrication of both onshore
and offshore structures.
This specification outlines the minimum quality and technical standards for materials, fabrication
and welding, testing, inspection and all personnel involved in the fabrication of structures used for
both the offshore and onshore environments. This document covers the arc welding of fillet, butt
and socket welds in carbon steels, low alloy steels, Austenitic stainless steels, Austenitic-Ferritic
stainless steels and Aluminium.
All the requirements of this document shall be strictly adhered too; no deviation shall be permitted
without a written approval from the Company.

All fabrication and welding activities shall be carried out in a safe manner in accordance with the
applicable codes and standards, to comply with the local government regulations.
Reference Codes and Standards
The following list of codes and standards are to be used in conjunction with this document, if any
conflicts exist between this document and the codes and standards listed; the requirements of this
document shall apply. The latest revision of all applicable codes and standards shall be adopted.
• BS 499-1 Welding Terms - Glossary for welding, brazing and thermal
cutting
• BS ENISO 17637 Non-destructive examination of fusion welds–visual
examination
• BS EN ISO 6520-1 Classification of geometric imperfections in metallic materials–
fusion welding
• BS EN 10204 Metallic products - Types of inspection documents
• BS EN ISO 2553 Welded, brazed and soldered joints – Symbolic representation
on drawings
• BS EN ISO 4063 Welding and allied processes - Nomenclature of processes and
reference numbers
• BS EN ISO 2560 Welding consumables - covered electrodes for manual
metal arc welding of non-alloy and fine grain steels -
Classification
• AWS A5.1 Specification for carbon steel electrodes
• AWS A5.4 Specification for stainless steel electrodes for shielded
metal arc welding
• AWS A5.5 Specification for low-alloy steel electrodes for shielded
metal arc welding
• BS EN ISO 14341 Welding consumables - Wire electrodes and deposits
for gas shielded metal arc welding of non-alloy and fine grain
steels - Classification
• BS EN 1011 Welding - Recommendations for welding of metallic
materials

DEFINITION OF TERMS
General
For the purpose of this document the following definitions shall apply. The terms used in this
documentation are in accordance with BS 499-1 and BS EN ISO 6520-1, other terms may be
encountered from other codes and standards not listed. Where terms encountered in this
document that are not clearly defined, common sense shall prevail.
Definitions
Company: TWI Ltd
Contractor: An entity performing specific work under contract of the company
Defect: An imperfection of sufficient magnitude to warrant rejection
Imperfection: A discontinuity or irregularity
Indication: Evidence obtained by Non-destructive testing
Welding: An operation in which two or more parts are to be united, by means
of heat or pressure or both.
Weld: A union of pieces of metal made by welding
Welder: The operator who performs the welding
Shop weld: A weld made within the premises of the manufacturer of the welded
assembly
Site weld: A weld made at the location where the assembly is to be installed
Parent metal: Metal to be joined or surfaced during welding
Filler metal: Metal added during welding
Heat affected zone: The part of the parent metal that is metallurgically affected by the
heat of welding
Joint: A connection where the individual components, suitably prepared
and assembled, are joined by welding
Manual welding: Welding in which the operator controls the welding parameters and
the means of making the weld are controlled by hand
Continuous welding: A weld extending along the entire length of the joint
Intermittent welding: A series of welds of the same type and dimension at intervals along
the joint
Arc welding current: Current passing through the electrode.
Are voltage: Electrical potential between contact tip or electrode holder and
work piece
Interpass temperature: Temperature in a multi-run and adjacent parent metal immediately
prior to the application of the next run
Heat input: Energy introduced into the weld region during welding per unit run
Length
Preheat temperature: Temperature of the work piece immediately prior to any welding
operations.
Shall: Denotes a mandatory action.
Should: Denotes a strongly recommended action.

Table 1 - Abbreviations and Symbols
Abbreviations and
symbols
Term
I
V
W
k
Q
a
d
h
l
s
t
z
CE
MTC
<
>
≤
≥
≈
Arc welding current
Arc welding voltage
Welding speed
Thermal efficiency factor
Heat input
Nominal throat thickness of a fillet weld
Diameter of pore
Height or width of imperfection
Length of imperfection in longitudinal direction of the weld
Nominal butt weld thickness
Parent material thickness
Leg length of a fillet weld
Carbon Equivalent
Material Test Certificate
Less than
Greater than
Less than and equal to
Greater than and equal to
Approximately

QUALITY CONTROL
Contractor Requirements
All contracting parties involved with the fabrication and welding of structures in accordance with
this document shall have in place a quality management system and quality control manual. This
document shall cover all construction activities.
Fabrication Requirements
All fabrication and welding activities shall be conducted in accordance with detailed procedures for
the control of quality. The following procedures shall be available and approved prior to the
commencement of fabrication and welding works, all welding and fabrication works shall be 100%
visually inspected.
• Welding and repairs
• Storage, control, and identification of welding consumables
• Welder qualification records
• Inspection/NDT
• Post weld heat treatments (where applicable)
• Parameter checks, and progress of welding
• Material traceability
• NDT traceability
• Inspection test plans (ITP's)
JOINT PREPARATION DETAILS
Base Metal Preparation
All surfaces to be welded shall be visually examined and shall be cleaned to bright metal for a
distance of not less than 30 mm from the edge of the weld bevel. All surface contaminants
including paints, oils, grease, or other foreign substances shall be removed from the weld bevel.
Surface cleaning should be carried out using power cleaning tools, any cleaning on flame cut bevels
shall be carried out using a disc grinder to a smooth finish sufficiently as to remove the first 3 mm
from the flame cut edge. Surface rusting shall be removed with a rotary wire brush, where the
area shows visible pitting, grinding and ultrasonic thickness checking shall be carried out to ensure
reduction of wall thickness has not exceeded 2%
Note: for specific details on stainless, duplex, QT steels and aluminium, refer to the
relevant sections of this document
Bevels
The welded bevels shall be bevelled to the dimensions specified in the approved procedure. In the
case of manual welding in the PA, PB, PE, PF, PG, PH, PJ, H-LO 45, J-LO 45 positions, the bevel
angle should be 30° +5° , -0°. In the PC position the bottom bevel 15° +5° , -0°, top bevel 45°
+5° , -0°. For alternative welding processes such as automatic welding alternative bevel angles
may be considered providing they are in accordance with the approved procedures.
All welded bevels shall be carried out by machining or by machine thermal cutting, manually or
mechanically operated. Manual thermal cutting shall not be used. The only time that manual
thermal cutting shall be considered is the cutting of pipes/plates for attachment fittings, weldolets,
sweepolets, etc., where machining or machine thermal cutting is not practicable and only if the
company gives approval.

Prior to fit-up all bevels shall be subjected to visual and Magnetic Particle (in the case of ferritic
materials) or Penetrant (in the case of non-ferritic materials) inspection.
Any indications found on the bevel faces, score marks, surface breaking laminations, mechanical
damage, lapping or any other imperfection shall be removed by grinding.
This shall be acceptable providing the thickness/depth of the repair area doesn’t exceed 3% of the
material thickness. This shall be qualified by the use of UT or a suitable depth-measuringgauge.
Where pipes/plates are to be cut back for the purpose of attachment fittings, a zone extending 90
mm back from the proposed position shall be fully examined visually and by ultrasonic inspection
for material imperfections, laminations, laps, folds, segregations etc. Visual acceptance is given in
section 9 of this document.
Alignment
The alignment of abutting ends shall minimize the offset between surfaces, for pipe and plate
ends, linear misalignment is permissible if the maximum dimension does not exceed 1.5mm.
Where parent materials of different thicknesses exist, the thinner of the two materials shall be
taken as the material thickness, in the case of plate welds angular distortion shall not exceed
5mm.
In the case of longitudinal seamed pipes/vessels, the longitudinal seams shall be offset by 90°.
Mitres of welded pipe joints shall not be permitted. Angular misalignment at the weld toes of less
than 3° is not to be classed as a mitre, and is acceptable providing that the angular misalignment
is equally distributed on both sides of the joint to a maximum of 1.5° per side.
In the case of fillet welds, unless otherwise specified, the fusion faces to be joined by fillet welds
shall be in as close contact as possible, maximum gap permitted shall not exceed 3 mm.
A fillet weld as deposited shall not be of less than the specified dimension, see section 5 for more
details.
Assembly for Welding
Parts to be welded shall be assembled in such a way that adequate access is available to all
personnel involved with the welding, inspection and other related activities for producing the
welded joint. Jigs and fixtures may be used where applicable providing no undue stress is applied
to the joint during the welding operation. To minimize stress and distortion it may be necessary
to pre-set joints prior to welding and/or to specify the welding sequence to assist in the control of
stress and distortion, e.g. back step/back skip welding.
Temporary Attachments
The use of temporary attachments may be used for the purpose of assembly where the applicable
procedures require them. They shall be used in such a way that they can be easily removed without
any damage occurring to the structure, all materials used for the temporary attachments shall be
compatible with the parent material. All temporary attachments shall be carefully removed after
use, where removal is carried out by air-arc gouging, arc gouging or flame cutting; the cut shall
be made clear of any parent material such that 3.0 mm of the temporary attachment is left for
final removal by grinding smooth. After such an operation, 100% inspection on the affected area
of the parent material shall be carried out. If any imperfections are found e.g. undercut or under
flushing these areas shall be blended smooth, they shall be considered acceptable proving the
depth doesn’t exceed 2% of the parent materials thickness. This shall be verified by the used of
ultrasonic inspection or a suitable depth gauge.
Note: Removal of temporary attachments by hammering or bending is not permitted.

Weather Conditions
All areas of welding shall be adequately protected from wind, moisture, snow blizzards etc.
Maximum air velocity for welding processes shall be limited as follows:
• 111. 20 mph (32 km/hr)
• 136. 15 mph (24 Km/hr
• 141. 5.0 mph (8 km/hr)
Note: The engineer shall state whether welding shall not be carried out because
prevailing weather conditions could impair the quality of the completed weld.
WELDING DETAILS
General Requirements
Only qualified welders shall carry out the welding in accordance with the applicable qualified
welding procedures. The surface to be welded shall be free from any contaminants, grease, paints,
scale, rust and any other foreign materials that may adversely affect the quality of the welded
joint. The joint design, root gap, root face, bevel angles, alignments etc. shall be in accordance
with this document and the approved welding procedure specifications applicable.
Butt Welds
All butt welds shall be welded in such a way that the entire groove is completely filled (at no point
shall the weld face be lower than the parent material). The ends of the butt weld shall be welded
in such a way as to allow the full length and thickness of the groove to be filled; this may be
achieved by the use of run-off/run-on plates. If required a suitable backing material may be used
to support the root during welding, this material shall be metallurgically compatible with both the
filler and parent plate/pipe material. No permanent backing materials shall be used.
In all butt welds, no joints shall be completed with a single pass welding technique, i.e. a minimum
of two weld passes shall be applied. Excessive weaving techniques shall be avoided with a
maximum weave of 2 times that of the electrode diameter permitted.
In the case of full penetration butt welds, which are to be welded from both sides, the back of the
first run shall be cleaned out prior to the welding of the second side. This shall be achieved by a
suitable means to clean to sound metal, this shall be inspected before commencement of welding
on the second side by both visual and magnetic particle inspection, in the case of non-ferrous
materials both visual and dye penetrant inspection.
Fillet Welds
Welding shall not have start/stop near corners; the welding shall be continued around the corners.
All fillet welds shall be made with a minimum of two weld passes, in the case of a two weld pass
fillet weld, the second pass to be applied as close to the extremity of the first pass without
impinging onto the pipe. Slip on flanges ≤ 100 mm shall have one weld run deposited on the inside
providing any tack welds are positioned on the backside prior to welding.
The deposited fillet weld dimensions shall be as follows:
Leg Length Throat Thickness
• Minimum = t Minimum = t x 0.7
• Maximum = t + 3 mm Maximum = t + 0.5 mm
Note: In the case of different thicknesses, welding is to be based on the minimum t

Preheating
For the welding of ferritic steels, the area of the joint that is subjected to preheat shall extend
around the entire periphery of the pipe or the parts to be welded. In each case the area extending
not less than 100 mm on each side of the joint shall be maintained at the required temperature.
Where practicable, the temperature shall be measured on the face opposite to that on which the
heat is applied. If this is not practicable, the temperature shall be confirmed on the heated faces
at a time after the removal of the heat source, this shall be related to the parent material thickness,
this is to allow for temperature equalization. The time shall be 2 minutes for a thickness not greater
than 25 mm, with an additional 1 minute for each 12 mm above that thickness. Preheating shall
be applied by either gas or electrical means but under no circumstances shall preheating be carried
out using a gas flame cutter. Care should always be taken to avoid damage to the parent material
and any applicable coatings.
The Minimum shall be determined by temperature indicating crayons, the type which melt or by
suitably attached calibrated thermocouples or pyrometers.
Note: Crayons or paints, which indicate temperature by colour change, are not
permitted.
The above only refers to the welding of ferritic steels, when welding stainless steels
preheat should be avoided. See section 14 for specific details on the welding of
stainless steels
The pre-heats are based on weldability trials and the following factors:
• Heat Input: Volts x Amps x k
Travel Speed x 1000
• Hydrogen Scale: A, B, C, D, E
• Combined Material Thickness
• Carbon Equivalent CE% = C + MN + Cr+Mo+V Ni+Cu
6 5 15
NOTE:- Thermal efficiency values to be applied.
Table 2 – Preheat Values
Hydrogen Scale A & B,
Heat Input
Value kj/mm
Temperature °C Combined
Thickness
Carbon Equivalent
(CE)
< 0.5 175°C Any thickness < 0.45 %
≥ 0.5 < 2.0 150°C Any thickness < 0.45 %
≥ 2.0 < 4.0 100°C ≤ 80 mm < 0.45 %
≥ 4.0 < 5.0 125°C > 80 mm < 0.45 %
≥ 5.0 No Preheat required Any thickness < 0.45 %
Table 2a – Preheat Values
Hydrogen Scale C, D & D, E
Heat Input
Value kj/mm
Temperature °C Combined
Thickness
Carbon Equivalent
(CE)
< 0.5 150°C Any thickness < 0.45 %
≥ 0.5 ≤2.0 125°C Any thickness < 0.45 %

≥ 2.0 < 4.0 75°C ≤ 80 mm < 0.45 %
≥ 3.0 < 4.2 50°C > 80 mm < 0.45 %
≥ 5.0 No Preheat required Any thickness < 0.4 %
Note: For CE values of 0.45% and above an additional 50°
C preheat temperature is
required from the values shown in the above tables.
Interpass Temperature
The maximum interpass temperature or preheat temperature for ferritic steels shall not exceed
250°C. The minimum interpass temperature shall not drop below the minimum calculated preheat
temperature. Temperatures shall be monitored by the same as for preheat temperatures.
Note: The above only refers to the welding of ferritic steels, when welding stainless
steels. See section 14 for specific details on the welding of stainless steels.
Arc Strikes
Arc strikes outside the weld groove area shall be removed by grinding. All arc strikes outside the
groove area shall be subjected to magnetic particle inspection. (In the case of non-ferritic steels
Penetrant inspection shall be used). All indications of cracking shall be again subjected to grinding
and re-inspection to ensure complete removal.
Where arc strikes have been repaired by grinding confirmation that the thickness of the parent
material is within the permitted tolerances, this shall be a thickness reduction of no more than 2%
of the original material thickness, confirmation shall either be by ultrasonic inspection or a suitable
depth gauge.
Weld Identification
A weld number shall identify all welds; if the weld has been repaired the letter “R” indicating a
“repair weld” shall follow the weld number. If the weld has to be removed the letters “RW”,
indicating a re-weld, shall follow the weld number. If the re-weld has to be repaired, the letters
“RWR”, indicating re-weld repair, shall follow the weld number.
Note: Either a permanent paint stick marker or a low stress metal stamp shall only be
used for weld identifications.
Interruption of Welding
Whenever possible, welding of joints shall be completed in one continuous operation. Where
interruption is unavoidable the following shall apply:
• For material thicknesses ≤ 25 mm, a minimum of two weld passes shall be completed over
the full weld thickness and length (root and hot pass).
• For material thicknesses > 25 mm, a minimum of three weld passes shall be completed
over the full weld thickness and length.
In the case of all joints, when welding is interrupted the joint shall be protected from
contamination, moisture etc. and shall be cooled in a slow uniform manner.
Prior to the recommencement of welding, the joint shall be subjected to the same preheat
temperatures as specified.
Note: In all cases the company shall approve all interruption of welding.
Tack Welding
In all cases the use of clamps is preferred over tack welding. If tack welds are to be used, tack
welding shall only be carried out by qualified welders, these tack welds shall be subjected to the
same preheat and interpass temperatures as groove/fillet welding and the following shall apply:
• All tack welds performed to hold members in alignment which will not be incorporated into
the completed weld (bridge tacking) shall be removed by grinding prior to the welding
approaching the tack area.
• All tack welds that will be incorporated into the completed weld, prior to the continuation
of welding, the tack weld shall be ground to a feather edge to permit acceptable weld

metal tie-in. The tack weld shall have a minimum length of 45 mm or 20% of the total
weld length whichever is the less.
Inter-run Cleaning
Each weld pass shall be thoroughly cleaned before the commencement of the next weld pass. The
cleaning may be performed by hand or power tools. All scale and slag shall be removed. All
stop/starts shall be blended smooth.
WELDING ACCEPTANCE LEVELS
General
All welds shall be subjected to visual inspection. Inspection of welds during welding shall be carried
out on the root pass where practicable. All weld caps shall be examined, all inspected welds shall
comply with the acceptance levels in this document, any imperfection found which does not comply
to the acceptance levels of the document shall be cause for rejection.
Excess weld metal
Excess weld metal (reinforcement) shall be uniform and not greater than 2.0 mm in height. The
toes of the weld shall blend smoothly with the parent material with no sharp indications visible.
The weld toes shall not extend into the parent material by more than 2.5 mm on either side of the
weld. At no point shall the weld face be lower than the plate/pipe surface.
Note: Acceptance for fillet weld sizes shall comply with section 5 of this document.
Root Profile
The root pass shall blend smoothly with the parent material with no sharp indications visible. The
penetration bead shall not exceed 3 mm.
Cracks
Not permitted
If cracks are found in a weld the entire weld shall be cut out, under no circumstances shall welds
with positively identified cracks be repaired.
Note: With the approval of the company, crater cracks of no less than 5 mm maybe
repaired.
Porosity and Cavities
Maximum permitted individual pore dimension
• Butt Welds: 1.5mm max
• Fillet Welds: 1.5mm max
In the case of elongated cavities (wormholes), the maximum length permitted shall not exceed 15
mm in any continuous or intermittent length.
In the case of clustered porosity the area shall not exceed 50mm2
.

Table 3 - Acceptance Criteria for Welds
No Defect Type Acceptance Criteria
1 Slag/Silica inclusions The length of the slag/silica inclusion shall not exceed 50 mm
in any continuous or intermittent length. Accumulative total
length shall not exceed 50 mm.
2 Undercut No sharp undercut shall be permitted. The maximum length
shall not exceed 50mm in any continuous or intermittent
length. Accumulative total length shall not exceed 50 mm. The
depth shall not be greater than 1.0 mm. Root undercut not
permitted
3 Lack of fusion Surface breaking lack of sidewall fusion shall not exceed 15
mm in any continuous or intermittent length. Accumulative
total length shall not exceed 15 mm in any weld length
4 Lack of root penetration Not permitted
5 Lack of root fusion Accumulative 50 mm max, continuous or intermittent
6 Burn Through Not permitted
7 Root concavity 50mm maximum length. 3mm maximum depth
8 Cold Lap/Overlap Not Permitted.
9 Oxidized Root Not Permitted.
10 Mechanical damage No stray tack welds permitted. All grinding/chipping/hard
stamping/hammer marks shall be blended smoothly
WELDING EQUIPMENT
General
The contracting parties carrying out the fabrication works shall be responsible for ensuring that all
the equipment required is in a good safe working order.
Welding and Cutting Equipment
All welding plant and cutting equipment shall have the capacity necessary to produce a sound weld
in accordance with the relevant procedures being adopted. All welding plant and cutting equipment
shall be calibrated every 3 months with maintenance records available. Cabling must be sufficiently
insulated and of a sufficient cross section to carry the required value without overheating.
Equipment not meeting these requirements shall be replace
Note: All welding plant shall have an OCV not exceeding 90 volts.
Equipment for Measuring
All equipment required for measuring shall have a valid certificate of calibration, calibration shall
be carried out every 12 months, these dates shall be clearly visible either on the measuring device
itself or be available in the form of documentation, with a clear traceability to the measuring device
in question.
Adequate means of measuring welding parameters such as welding current, welding voltage and
travel speeds shall be available.

WELDING CONSUMABLES
General
Electrodes, filler wires, wire/flux combinations and flux types shall be such that they produce a
sound weld meeting the requirements of the applicable procedures being adopted. The completed
weld metal shall have a tensile strength value at least equal to the minimum specified for the
parent material. In the case of dissimilar joints, the weld metal shall have a tensile strength at
least equal to that of the higher strength material.
The chemical composition of the deposited weld metal shall be compatible to that of the parent
material. All welding consumable shall be free from damage, chips, contamination, and used within
the recommendations of the manufacturer.
Storage and Handling
All SAW fluxes shall be stored in accordance with the manufacturer’s recommendations. SAW flux
maybe recycled provided the reused flux is free from all contaminates, slag, mill scale and another
foreign matter. All recycled fluxes shall be mixed with an equal amount of new flux before being
used (50:50ratio)
All MMA welding consumable shall be treated in accordance with the manufacturer's detailed
recommendations. When it is necessary to dry and bake the consumable, the consumables shall
be removed from its original container prior to any applicable heat treatments, after the heat
treatment the consumables shall be stored in such a way as to keep them free from moisture
intake, i.e. drying ovens. In the case of consumables that have been vacuum packed, these shall
be used in accordance with the manufacturer’s recommendations. In the case of hydrogen
controlled consumables it is recommended that the welders be issued with electrodes in a heated
quiver.
Note: All drying and baking ovens for welding consumables shall be provided with the
means of measuring the oven temperatures.
Shielding gases shall be stored and kept in the original supplied containers and these shall be
stored in such a way as to avoid extreme temperatures. Gases shall only be used in the containers
supplied by the manufacturer with no mixing of gases to be conducted on site. All gas containers
shall be clearly marked without any signs of damage; containers, which don’t comply, shall not be
used.
MATERIALS
General
All materials to be used in fabrication shall be in a clean, corrosion free condition; no evidence of
surface pitting shall be visible. Materials with laminations shall not be used in any fabrication,
C-Mn steel >25mm thickness must have a lamination check and this must be referenced on the
mill certificate. Materials not having a valid mill certificate shall not be used under any
circumstances. Both contractor and client inspectors shall inspect all materials arriving on site;
materials not complying with the requirements shall be quarantined until the materials do comply
with the requirements of this document. All materials arriving on site shall only be purchased from
company approved manufacturers list.

Material Requirements
• All structural steel shall be new stock.
• Spiral welded pipe shall not be used.
• Electric-resistance welded (ERW) pipes shall not be used.
• No materials with a CE% above 0.48 shall be used for fabrication purposes.
• Contractor shall maintain all material traceability, showing the material heat numbers
of all major load bearing structural members.
• Contractor shall mark each mill certificate with the contractor’s job number, item
number to be used, quantity to be used, e.g. number of meters and the area of structure
for the material.
Contractor shall maintain traceability maps showing the material heat numbers of all major load-
bearing structural members.
Note: for specific details on stainless, duplex, QT steels and aluminium, refer to the
relevant sections of this document
Material Marking
All steels shall be suitably marked upon delivery to the contractor’s fabrication yard. The steel
shall be marked in such a way that the type of steel, heat number and any applicable special tests
can be easily recognized.
All heat numbers or other identification markings shall be transferred from piece to piece prior to
cutting, cut pieces shall be remarked in the same way as the original markings.
All markings shall be stencilled with a suitable marker or a low stress concentration die on both
ends of each item.
Material Storage and Handling
All structural materials shall be stored above ground on flat surfaces or platform type skids.
Materials shall be stored in such a way that they are kept free from dirt, grease, paint spray or
any other foreign matter and kept free from corrosion. In the case of stainless steel grades these
shall be stored in a separate area from ferritic steels, covered over at all times, and no contact to
be made with ferritic materials at any time, e.g. fork lift trucks shall be suitably protected against
steel to steel contact, all lifting equipment shall be used in such a way as to avoid ferritic contact
with the stainless materials.
DEFECT REPAIR AND CUT-OUTS
General
All weld repairs shall be conducted in accordance with the weld repair procedures and only
conducted by qualified welders. No weld repair or cut-out shall be conducted without the
authorization of the company. All repairs shall be witnesses 100% by a qualified welding Inspector.
A weld may only be repaired once, if the weld still contains unacceptable defects in accordance
with this document the entire weld shall be removed. Cracks, see general acceptance levels section
6.
Removal of Defects
All welds that fail to comply with the requirements of this document shall either be repaired or the
entire weld removed. Repairs shall not be carried out until full inspection has been conducted.
Defects shall be removed by grinding or air-arc gouging. When arc-air gouging is employed, the
resultant removal cavity shall be ground to clean base metal before any welding can commence.
Entire weld removal may be carried out by thermal cutting.

When thermal gouging or thermal cutting is being used, the last 10% through the root of the weld
shall be removed by mechanical grinding.
Preparation for Re-Welding
In the case of a partial weld removal, the cut out portion shall be sufficiently deep and long enough
to remove the entire defect. At the ends and sides of the excavation area there shall be a gradual
taper from the base of the cut to the surface of the weld metal. The width and profile of the
excavation shall give adequate access for re-welding. The repair groove shall be inspected by dye
penetrant or magnetic particle inspection to ensure that the defect has been entirely removed.
In the case of a cut-out, involving the entire defective weld to be removed, the weld preparation
shall be re-made in accordance with the requirements of this document.
Re-Welding
A repair weld shall be subjected to the same testing and inspection as the original weld, with a
pre-heat temperature 75o
C above that of the original weld preheat temperature. Repair welds shall
be limited to 25% of the original weld length, defects that exceed this value require the entire
weld to be removed. All re-welding shall only be carried out under full supervision from a qualified
welding inspector; no vertical down welding is permitted for weld repairs. Full records and reports
of all repairs shall be maintained.
NON-DESTRUCTIVE TESTING
General
Contractor shall propose specific procedures for all NDT methods to be used e.g. MPI, DPI, UT and
RT. Contractor shall only use NDT personnel qualified to EN ISO 9712 level II as a minimum in the
applicable discipline, this also includes any third party inspection services. All third party inspection
service companies can only be used with approval from the company.
Whenever radiography is employed as the main NDT method, a percentage of welds shall be
inspected by ultrasonic testing. As a minimum 100% of the first 10 welds, after which 100% of
one weld after every 25 welds completed.
Note: 100% of the weld shall be tested by the inspection method being used.
Equipment
All contracting and third parties conducting NDT shall provide a full list of all inspection equipment
to be used including all relevant calibration certificates; this shall also include a comprehensive
spare parts list.
Health and Safety Requirements
Contractor shall be solely responsible for all safety concerns associated with the NDT methods
being employed. When using radioactive materials these shall comply with the government
regulations and possess a permit from the relevant national atomic energy agency.
Documentation and Records
All completed NDT reports shall be submitted to the company for approval and signature. The NDT
technician performing the inspection shall sign all reports.
All NDT reports shall have an original copy issued to the company and a soft and hard copy retained
in the job file.
All discontinuities detected shall have both the length and position from datum reported. UT
reports shall also include the discontinuities depth.

Magnetic Particle Inspection Details
General
MPI is for the purpose of detecting surface discontinuities in ferrous butt welds, fillet welds and
ferromagnetic components. Wet method MPI shall be used in all cases except for the inspection of
hot materials and components (>60°C).
Equipment and Consumables
Magnetization shall only be carried out using an AC Yoke (DC Yokes shall not be used). Pole
spacing’s shall be a minimum of 150mm and a maximum of 300mm. AC yolk lift test with a weight
of 4.5kg, Permanent magnets lift test with a weight of 18kg
Magnetizing method to be used shall show three indications on a Castrol Burma Strip (Brass type).
If this cannot be achieved then the magnetizing method must be changed or adjusted.
Indicating medium shall be a water or solvent suspension of black ferromagnetic particles. Only
company-approved trade names may be used. Indicating medium shall be periodically agitated to
assure correct concentration of particles, only aerosol magnetic inks supplied by the manufacturer
shall be used. Where black ink particles are being used a white contrast paint shall be applied prior
to inspection, this shall be supplied by the same manufacturer as the black ink particles i.e. no
mixing of manufacturers shall be permitted.
Note: The use of permanent magnets shall only be used on live plant as a safety
precaution and then only by prior Company approval.
Fluorescent methods shall not be considered.
Material Preparation
All surfaces at least 30 mm either side of the area to be tested shall be free from welding slag,
scale, grease, oil, excessive weld spatter and any other foreign material which may interfere with
inspection.
Techniques
• Apply white contrast paint where black particles are to be used.
• Magnetize the weld area or area to be inspected. Large weld areas may require multiple
inspections to cover the entire surface or test area to be inspected.
• While the component is magnetized, apply ink and inspect for indications. Black particle
inks shall be inspected in a well-lit area of no less than 500 Lux.
Evaluation of imperfections shall be assessed in accordance with section 6 of this document.
Dye Penetrant Inspection Details
General
DPI shall only be used for the detection of surface breaking defects on non-ferrous materials e.g.
austenitic grade stainless steels, Duplex grade stainless steels and copper, Aluminium based

materials. Colour contrast solvent based penetrants shall be used at all times, the use of any other
penetrant method e.g. water based or fluorescent may only be used with company approval. DPI
shall only be used at a temperature between 10°C and 50°C
For colour contrast inspections the test area shall be illuminated by daylight or artificial light not
less than 500 Lux.
When company permits fluorescent inspections the UV-A irradiance at the surface under inspection
shall not be less than 10 W/m2
(1000 m W/cm2
) with a maximum background light of 20 Lux.
Only company approved trade names shall be used, all consumables used shall be from the same
manufacturer i.e. no mixing of manufacturers shall be permitted.
All surfaces at least 30 mm either side of the area to be tested shall be free from welding slag,
scale, grease, oil, excessive weld spatter and any other foreign material which may interfere with
inspection. All surfaces to be inspected by DPI shall be cleaned thoroughly using a solvent based
cleaner.
Techniques
• Cleaning, all cleaning shall be carried out as above
• Application, the entire area to be tested shall have a uniform coating of penetrant applied
by spraying or brushing. Penetrant shall be left in contact with the component under test
for a minimum of 5 minutes and a maximum of 15 minutes; at no time shall the penetrant
be allowed to dry. If this does occur the penetrant process must be started again.
• Penetrant removal, all excess penetrant shall be removed initially by wiping with a lint free
cloth. If further traces of penetrant are still present, this may be removed by a solvent
dampened cloth; under no circumstances shall solvent remover be applied directly to the
component. Before the application of the developer it is essential that all surfaces are
completely dry.
• Application of Developer, a non-aqueous developer shall be applied uniformly in a thin
layer across the entire test surface
• Inspection, inspection of the test surface shall start immediately the developer is applied,
any signs of penetrant bleed-out may indicate the presence of discontinuities.
Evaluation of imperfections shall be assessed in accordance with section 6 of this document.
Ultrasonic Inspection Details
General
UT shall be used for the detection of sub-surface discontinuities; UT shall not be carried out on
any Austenitic grade stainless steels. Duplex stainless steels and Aluminium may be considered
providing sufficient attenuation checks have been conducted and then only by company approval.
All UT technicians supplied by either contractor or third party NDT companies shall be subjected
to company UT cross checking. UT shall only be considered as a primary NDT method for the
following:
• Material thicknesses > 80 mm
• Tee butt welds
• Cruciform Butt welds

• Set-through Butt welds (including nozzles)
• Set-on Butt welds (including nozzles)
Couplant used shall be a gel or grease (water based couplants shall not be considered) suitable
for transmission of sound waves into the material under test. Couplant used for calibration shall
be identical to that used for testing.
Reference blocks shall be V1 (A2) and or V2 (A4), IOW Black (used for beam profiles) and RC
Block (used for resolution checks).
Probes to be used for weld body scanning (cap as welded) are 45°, 60° and 70°
refraction angles,
4MHz to 5Mhz frequency with a single crystal area approximately 80 mm2
. Parent material
scanning and weld cap dressed flush, 0° 4MHz to 5MHz with a twin crystal area approximately 80
mm2
.
The detection unit used shall be calibrated and shall be capable of operating with a frequency
range of 1.5 MHz to 6 MHz.
Note: For materials < 15mm, the omission of a 450
probe shall apply
Before ultrasonic inspection is carried out a zone of sufficient size (no less than 90 mm) shall be
thoroughly cleaned with all spatter, scale, slag removed, either side of the weld. Any paint or other
surface coatings, which interfere with the weld scanning, shall be removed. The surface profile
shall be sufficiently regular as to permit a uniform contact between probe and parent material
throughout the test. When echoes from the reinforcement are likely to interfere with the test, the
reinforcement shall be dressed to a smooth profile. Prior to inspection the area adjacent to the
weld is to be inspected by a 0o
compression probe to confirm the material thickness under test
and to detect the presence of any laminations, which may interfere with the ultrasonic inspection.
Scanning
Test sensitivity for angle probes shall be set so that the echo from a 1.5 mm side drilled hole
(V1(A2) or V2(A4) block) is 80% full screen height. Test sensitivity for compression probes shall
be set so the 2nd
back wall echo from test depth is 80% full screen height. In both cases, when
scanning an addition 6 dB shall be added. The weld shall be scanned in a zig zag manner, the
probe being moved between the weld reinforcement and skip distance/full skip distance. The beam
shall be directed at the weld length normally. The weld shall be scanned from both sides.
Evaluation of imperfections shall be conducted in accordance with section 6 of this document.
The methods which shall be used for the sizing of any imperfection found.
• 20 dB drop method: for imperfections with dimensions smaller than the
probe beam spread at the discontinuity beam path.
• 6 dB drop method: for imperfection with dimensions larger than the
probe beam spread at the discontinuity beam path.
Note: Automatic Ultrasonic Inspection may be considered but only with the approval
of the company.

Radiographic Inspection
General
RT shall be used for the detection of sub-surface discontinuities (surface discontinuities may also
be detected with RT which may have been missed by a surface detection NDT method) RT shall
be considered as the primary NDT method unless the conditions of 11.7.1 exist. RT (X and/or
Gamma) shall be conducted on Butt Welded Joints (including the HAZ area) for pipes, plate,
vessels and structures of both ferrous and non-ferrous materials. Radiography shall only be
conducted by personnel holding a current national radiation safety certificate.
Radiation sources Ir 192 shall have a maximum source dimension of 2 x 2 mm; no sources shall
be used for the purpose of weld inspection that have an intensity less than 444 GBq. For the
purposes of safety a maximum of 60 Ci isotopes are permitted for use on site. The use of Se 75
is preferable for the inspection of welds with a penetrated thickness up to 40 mm.
X- Ray units shall be capable of an output not less than 250 KV, with a focal spot size no greater
than 4 x 2 mm; this shall be checked every six months.
Radiographic film shall be of the fine grain type, high contrast direct type and for all gamma
radiography and X radiography above 120 KV's, lead screens shall be used. All unexposed film
shall be stored in a clean dry area where surrounding conditions will not deteriorate the condition
of the film
All chemicals used for the processing of films shall be in accordance with the manufacturer’s
recommendations.
The following equipment shall be available in the viewing area:
• Densitometer with a certified density strip
• Film viewer capable of viewing films of exposed densities over 3.5 H&D
• Magnifying glass (10x magnification)
• All applicable codes and standards
Film Identification, films shall be identified as to the company requirements with 6 mm lead letters.
A number belt with numbers at 1 cm intervals shall be used to ensure complete coverage. The
minimum identification to be provided on the radiograph shall be:
• Date
• Job Number and Weld Identification number
• Datum point
• Penetrometer (IQI)
Radiographic Sensitivity
Exposed radiographs shall have an average H&D density at the sound weld metal image of a
minimum of 2.0 and a maximum of 3.5, the density shall be assessed by a calibrated densitometer.
ISO EN wire type penetrometers shall be used with a minimum sensitivity calculation of 2% in the
weld image area.
Maximum Ug levels shall not exceed 0.25 mm unless approved by Company; this shall only be
considered when it is proven that the radiographic technique being used can’t achieve this value.

Techniques
The following radiographic techniques (where possible and practicable) shall be used as required
to ensure full radiographic coverage.
• Double wall Double Image (DWDI) for pipe diameter up to 100 mm, minimum of three
exposures
• Double Wall Single Image (DWSI) for pipe diameters above 100 mm. Pipe diameters up
to 660 mm, a minimum of four exposures are required. Pipe diameters above 660 mm to
1100 mm, a minimum of 5 exposures are required. Pipe diameters above 1100 mm require
a minimum of 6 exposures; more may be required as to the Company requirements.
• Single Wall Single Image (SWSI) minimum 150 mm SFD
• Single Wall Single Image (Panoramic) source inside, film outside, this technique is
preferable for all pipe diameters > 300 mm
Note: Minimum SFD/FFD shall be calculated using the material thickness and the
maximum Ug value (0.25 mm) permitted.
Note: Only an BS EN ISO 9712 Radiographic level II qualified person shall be permitted
to sign off viewed radiographs.
INSPECTION PERSONNEL
General
All personnel involved with the inspection of welds and related activities shall be qualified to a
minimum of level II and certified by an approved certification body, which meet the current
requirements of BS EN ISO 9712
Vision Requirements
All inspection personnel shall have satisfactory vision as determined by an oculist, optometrist or
medically recognized person in accordance with the following requirements
1. Near vision acuity shall permit reading a minimum of Jaeger number 1 or Times Roman N
4 at not less than 30 cm with one or both eye, either corrected or uncorrected.
2. Colour vision shall be sufficient that they can distinguish and differentiate contrast between
colours used in the NDT method concerned as specified by the company.
Note: A documented vision test shall be carried out at least once a year.
RECORDS AND REPORTS
General
Contractor shall provide Company's welding inspector with a daily report of all welding and related
activities. The report shall show as a minimum, weld number, radiograph number (if applicable),
All UT, MPI, DPI report numbers (If applicable), status of each welded joint (accepted, repaired
and accepted, rejected or cut-out), welder(s) ID numbers, heat treatment reports and any other
applicable details. The reports shall be presented on a format approved by the Company; no other
report formats shall be permitted.
Frequency of Reports
The time between inspection date and report shall not exceed 48 hours for all inspection methods.

SPECIFIC DETAILS FOR WELDING STAINLESS AND DUPLEX STAINLESS STEELS
General
All fabrication of stainless steel and duplex grades shall be segregated from all other works and
kept free from any possible contaminating materials such as copper, carbon steels, zinc etc.
All tools used in the fabrication of stainless steels shall be kept separate from other tools and
clearly marked with a colour code. This includes grinding wheels; wire brushes (stainless wire
only) etc. and should be kept in thoroughly cleaned condition. All workbenches shall be either
stainless steel or suitably covered with a covering material of sufficient thickness as to avoid
carbon to stainless contact.
All stainless steels shall be stored under cover and on wooded blocks of sufficient thickness for the
material to be stored a minimum of 320 mm off the ground.
Material Details
All Austenitic Stainless steels for fabrication welding shall be of the grade 316L, with a maximum
carbon content of 0.03%. All Austenitic Stainless Steels shall be supplied in a solution-annealed
condition, de-scaled, pickled and passivated. Any cold working should be carried out before final
heat treatment. All Austenitic Stainless Steels shall be subjected to positive material identification
(PMI) before being issued for site use for alloy content verification.
All Duplex Stainless Steels for fabrication and welding shall have a Nitrogen content not lessthan
0.14% and a ferrite content between 40% and 60% for the base material and 30% to 55% for
the weld metal. All Duplex Stainless Steels shall be supplied in a solution-annealed condition, de-
scaled, pickled and passivated, after welding the weld shall undergo the same treatment. Any cold
working should be carried out before final heat treatment. All Duplex Stainless Steels shall be
subjected to a ferrite check after welding and positive material identification (PMI) before being
issued for site use for alloy content verification.
Joint Preparation Details
Generally no special joint preparations are required for the welding of Austenitic Stainless steels
and Duplex stainless steels. Any thermally cut bevels for welding shall be mechanically ground or
machined back from the cut edge by at least 5 mm to eliminate any contamination from the
thermal cutting process. Hard stamping should be avoided; when this is unavoidable the hard
stampings shall be of the rounded type and not applied in any high stress concentration areas.
Welding Details
The use of preheat should be avoided and may only be considered when approved by the
Company. All welding of stainless steels and duplex grades shall be monitored 100% by an
approved welding inspector with amps, volts, travel speed and heat input being recorded at all
times, these records shall be made available to the company upon request. Only welding process
141 shall be used for the root pass and second pass on all Austenitic and Duplex stainless steels,
other welding processes may be considered for the filler and capping passes with Company
approval. In all cases stringer beads only shall be applied. Shielding gasses for both Austenitic and
Duplex stainless steels shall be of a purity of 99.99% Ar with oxygen content for backing gasses
prior to welding 500ppm maximum.
The following variables shall be strictly adhered to at all times:
• Heat Input: 18 to 22Cr 0.5 to 1.75 KJ/mm
• Heat Input: 23 to 25Cr 0.5 to 1.50 KJ/mm
• Interpass Temperature: 18 to 22Cr 175o
C Maximum

• Interpass Temperature: 23 to 25Cr 150o
C Maximum
After welding it is essential that all surface slag, scale and any other contaminations are removed
this may be conducted by mechanical means or by wire brushing (stainless steel only).
Post weld heat treatments are generally not necessary for both Austenitic and Duplex stainless
steels. Heat treatments however may be required for the purpose of stress reliving after extensive
cold working, cold deformation etc. These heat treatments may only be carried out if approved by
Company at a maximum temperature of 450°
C
Non Destructive Testing Requirements
For both Austenitic and Duplex stainless steels the following shall be applied
• 100% Visual Inspection on all welds
• 100% Dye Penetrant on all welds
• 100% Radiography on all butt welds
Note: Ultrasonic Inspection may be considered as a back-up only on Duplex stainless
steel and only with prior Company approval.
SPECIFIC WELDING DETAILS FOR ALUMINIUM AND ALUMINUM ALLOYS
General
All fabrication of Aluminium and Aluminium alloys shall be segregated from all other works and
kept free from any possible contaminating materials such as copper, carbon steels, zinc etc.
All tools used in the fabrication of Aluminium and Aluminium alloys shall be kept separate from
other tools and clearly marked with a colour code. This includes grinding wheels; wire brushes
(stainless wire only) etc. and should be kept in thoroughly cleaned condition. All workbenches
shall be free from any ferritic base material or suitably covered with a covering material of
sufficient thickness as to avoid ferrite to aluminium contact.
All aluminium and aluminium alloys shall be stored under cover, Plates are to be stored in the
vertical position as to minimize moisture condensation and long term moisture collection between
layers. All aluminium and aluminium shall be stored on wooded blocks of sufficient thickness for
the material to be stored a minimum of 320 mm off the ground.
Note: All filler materials and base materials shall be brought into the welding area no
less than 24 hours before the commencement of all welding operations, to ensure they
are at room temperature.
Material Details
Series 1XXX, 3XXX and 7XXX aluminium and aluminium alloys shall not be used for the purpose
of fabrication and welding. All aluminium and aluminium alloys shall be free from all cutting oils
and other contaminations.
Joint Preparation Details
All cutting of Aluminium and aluminium alloys shall be conducted using either; plasma arc, laser
or by suitable mechanical means (the use of cutting lubricants shall be avoided). The use of oxy-
fuel gas cutting, carbon arc cutting or gouging shall not be used. When plasma and laser cutting
is used on series 2XXX and 6XXX, a minimum of 3 mm shall be removed by mechanical means
from the cut edge, after removal the cut edge shall be inspected by DPI to ensure no cracking is
present on the cut edge.

Note: when cutting Aluminium by thermal methods on series 2XXX and 6XXX the cut
edge my contain solidification cracking and detrimental parent material conditions.
Before the commencement of welding all fusion faces shall be cleaned and degreased by solvents
and the oxide layer removed by mechanical means. The period between cleaning and welding shall
not exceed 30 minutes to avoid recontamination.
Note: Degreasing by chemical etching will remove the surface oxide; this method can
be considered but only by Company approval. If chemical etching is to be used, stainless
steel wire brushing shall be carried out on all etched surfaces to remove the by-product
residuals which may have a detrimental effect on the weld quality.
In all cases after cleaning the fusion faces shall be free from moisture, compressed air
blowing should be avoided as compressed air my contain moisture and oil contaminates.
Table 4 – Joint details for Aluminium Butt Welds
Welding
Position
Material Thick Root Gap Root Face Included Bevel
Angle
PA
< 12.5 mm 0 to 0.5 mm 0 to 0.5 mm 0°
to 70°
12.5 to 25 mm 0.5 to 1.25 mm 1.6 to 3.2 mm 70°
> 25 mm 0.5 to 1.5 mm 2.0 to 4.5 mm 70°
PC, PE
< 12.5 mm 0.5 to 1.25 mm 0 to 1.6 mm 0°
to 70°
≥ 12.5 mm 1.0 to 1.5 mm 1.6 to 3.2 mm 70°
PF, PH,
H-LO45
< 12.5 mm 0 to 1.0 mm 0 to 1.6 mm 0°
to 70°
≥ 12.5 mm 1.0 to 1.5 mm 1.6 to 3.2 mm 70°
Fillet weld dimensions shall be in accordance with section 5.3 of this document.
Note: PG, PJ and J-LO45 welding positions shall not be considered for the welding of
Aluminium and aluminium alloys.
Welding Details
Only welding processes 141 and 131 shall be considered for the welding of aluminium and
aluminium alloys. In both argon (99.997% pure) shall be used as a shielding gas. All pipe butt
joints to be welded using process 141
Note: argon/helium mixes may be considered but only by Company approval and only
by using fully approved WPS’s
During the welding duration for both 131 and 141 welding processes, interpass temperatures shall
not exceed 110°
C; series 6XXX aluminium shall not exceed 90°
C.
Pre-heating shall not be applied to heat treatable base materials and series 5XXX base materials
containing Mg contents above 3%. All other base materials shall be subjected to a pre-heat
temperature as to the approved WPS, but no greater than 120°
C.
15.6 Process 131
• Leading arc (push) technique to be used for increased cleaning action.
• Spray transfer mode (pulse transfer mode may be considered for positional welding and
on thinner materials < 3.5 mm)
• Filler wire to match the melting point as close as possible to the base materials melting
point.
• Constant voltage characteristic welding plant.
• Travel speeds shall not be less than 6.5 mm/s
• Welding current DC EP
• Heat Inputs

Table 5– Process 131 Heat Input Values
Material Thickness Minimum Heat Input
(KJ/mm)
Maximum Heat Input
(KJ/mm)
< 3.5 mm 0.24 0.32
≥ 3.5 mm < 6.5 mm 0.35 0.41
≥ 6.5 mm 0.57 0.85
15.7 Process 141
• Filler wire to match the melting point as close as possible to the base materials melting
point.
• Constant current characteristic welding plant.
• Zirconiated or Lanthanated tungsten electrode (smooth hemisphere electrode tip)
• Electrode diameter as to the approved WPS, min diameter 1.6mm, max diameter 4.5mm
• Welding current AC
• Heat Inputs
Table 5a – Process 141 Heat Input Values
Material Thickness Minimum Heat Input
(KJ/mm)
Maximum Heat Input
(KJ/mm)
< 3.5 mm 0.42 0.57
≥ 3.5 mm < 6.5 mm 0.89 1.2
≥ 6.5 mm 1.98 3.2
15.7 Non Destructive Testing Requirements
For aluminium and aluminium alloys, the following shall be applied
• 100% Visual Inspection on all welds
• 100% Dye Penetrant on all welds
• 100% Radiography on all butt welds
Note: Ultrasonic Inspection may be considered as a back-up only on Duplex stainless
steel and only with prior Company approval.
SPECIFIC WELDING DETAILS FOR QUENCHED AND TEMPERED STEELS (QT Steels)
General
No special joint requirements are required for QT steels, material preparations, joint
configurations, bevel angles etc. shall be carried out in accordance with section 4 of this document.
Only Grade A514/QT-100 steels shall be considered, specified minimum yield 100,000 psi (689
N/mm2), maximum 110,000 psi (758 N/mm2
) UTS, for thicknesses up to 63 mm. QT steel Plate
thicknesses > 63 mm shall not be considered for fabrication and welding unless specifically
approved by Company
Welding Details
All welding operations shall be conducted using a welding process/welding consumable capable of
depositing hydrogen levels < 10 ml of hydrogen per 100 g of weld metal deposited (scale B). If
the MMA welding process is being used for the welding operations the use of a basic (Low
hydrogen) electrode only may be considered. The electrode shall be baked/dried in accordance
with the manufacturers recommendations and the approved consumable procedure (refer to
section 8 of this document)
Note: All basic electrodes shall be issued in quivers (hot boxes) at a temperature
between 70°
C to 90°
C; all returned electrodes shall not be re-baked.
If the SAW welding process is being used only agglomerated-high basic fluxes shall be considered.

All flux treatments shall be carried out in accordance with the manufacturers recommendations
and the approved consumable control procedure (refer to section 8 of this document)
Note: When using SAW on QT steels the flux recycling shall only be permitted to a ratio
of 50% new to 50% old.
When welding QT steels with the MMA welding process the electrode must match the materials
UTS value as close as possible, only electrodes depositing between 110,000 psi UTS (AWS A5.5
E110 1 8 M) to 120,000 psi UTS (AWS A5.5 E120 1 8 M) values shall be considered.
Note: Welding processes 131, 135 and 136 shall not be considered for the welding of QT
steels.
Minimum preheat values and interpass temperatures shall be as follows:
Table 6 – Minimum Preheat and Interpass Temperatures for QT Steels
Note: Preheat temperature shall not exceed 110o
C
Table 6a – Minimumm Heat Input Values for QT Steels
Preheat
Temperature
Plate Thickness
< 12.5 mm ≥ 12.5 to
25mm
≥ 25 to
≤50mm
>50 mm
25°
C 0.9 KJ/mm 2.24 KJ/mm 4.7 KJ/mm 6.06 KJ/mm
75°
100°
150o
Non Destructive Testing Requirements
No special inspection requirements are required for QT steels. All NDT requirements shall comply
with section 11 of this document. Evaluation of imperfections shall be conducted in accordance
with section 6 of this document.
QUALIFICATION OF WELDING PROCEDURES
General
For all new welding procedure qualification tests, contractor shall submit to Company a Preliminary
Welding Procedure Specification (pWPS) for approval before the commencement of the
qualification test. Contractor shall also submit to Company a repair pWPS for all main welding
procedures. In the case of Stainless steels and Duplex stainless steels pre-qualified WPS's shall
under no circumstances be used. In the case of carbon steels generally, unless approved by
Company pre-qualified WPS, shall not be permitted for use. WPS's previously used by a Contractor
and meeting all the requirements of this document may be submitted to Company for approval.
Only WPS's approved by Company shall be used.
Approval and testing of welding procedure specifications shall consist of the following stages
I. The Contractor shall submit to the Company a detailed pWPS for all welding and repair
welding procedure specifications
II. The Company shall provide approval before any testing can commence
Plate Thickness Minimum Preheat Temperature Minimum Interpass Temperature
< 12.5 mm 25°
C 20°C
≥ 12.5 to 25 mm 50°
C 50°
C
≥ 25 to ≤ 50 mm 75°
C 80°
C
> 50 mm 100°
C 100°
C

III. Before any production welding can commence, test welds shall be made using these
procedures under simulated site conditions.
IV. The quality of the test welds shall be determined by non-destructive and destructive
testing after the specimens have been allowed to cool to ambient temperature for no less
than 48 hours.
V. For the WPS's to be approved for use in production the test results shall meet the
requirements of this document.
Note: If the test piece fails to comply with the requirements of this document, one
further test piece may be welded and subjected to the same test conditions. If the
second test piece fails the pWPS it is to be considered as rejected and a new pWPS shall
be submitted to Company for approval.
All welding procedures shall be submitted and approved by Company prior to their use. This shall
include a Welding Procedure Specification (WPS), Welding Procedure Approval Record (WPAR),
with all supporting documents for materials, NDT and destructive testing. All Company approved
WPS's used for production welding shall be clearly displayed at all work locations.
Essential Variables
When any of the changes given in table 7 are made to the WPS, the WPS shall be re-qualified and
fully approved under the same conditions as the original.
Table 7 - Changes Affecting Approval - Essential Variables
Welding process 1. From one process to another.
2. From manual to semi-automatic or mechanized welding
process or vice-versa
Material specification Any significant change in grade and condition
Material thickness Any change in thickness of ± 20% of the minimum t
Joint configuration Any change in joint configuration outside the tolerances of this
document.
Filler metal type Any change from trade name and classification type
Filler metal diameter Any change in diameter used for the root pass and second
pass. Any changes for the other runs to a larger diameter.
Shielding gas and flow rate Any change
Shielding flux Any change in flux type and trade name
Electrical characteristics Any change in current type or polarity
Welding Position See 17.9
Direction of welding Any change in direction
Time lapse between Any increase in time between completion of weld pass and
commencement of next pass
Partially completed joint Any changes from the requirements of this document
Preheating Any changes from the requirements of this document
Interpass temperature Any changes in temperature
Post weld heat treatment Any changes form the approved procedure
Welding parameter Any changes by 15% in the specified values of current,
voltage, wire feed speed, run out length or travel speed.
Welding of Test Joint
Preparation and welding shall be carried out in accordance with the pWPS, and under the simulated
production conditions. If tack welds are to be fused in to the final joint they shall be included in
the test piece. All weld passes shall be cleaned until free from slag and visible defects prior to the
deposition of the next run. All welding shall be inspected/monitored 100% throughout the test
piece welding by both Contractor and Company inspectors

Note: All completed procedure welds shall be left in the as welded condition; surface
dressing on the cap may be permitted but only after visual inspection has been carried
out by Company inspector.
Extent of Testing
The testing to be carried out on the test pieces are both non-destructive and destructive test
methods. The tests required shall be in accordance with Table 8 and Table 8a.
Table 8 - Examination and Testing of Test Pieces Non-Destructive Requirements
Test Piece Type of Test Extent of
Test
Note
Butt Welds Visual
Radiographic or Ultrasonic
Magnetic Particle or Dye Penetrant
100 %
100 %
100 %
Please refer to
Figures 4 for
joint
configurations
for UT
T-Butt Joints Visual
Ultrasonic
100 %
100 %
100 %
Please refer to
Figures 4 for
joint
configurations
for UT
Fillet Welds Visual
100 %
100 %
Other Welds Visual
Radiographic or Ultrasonic
100 %
100 %
100 %
Please refer to
Figures 4 for
joint
configurations
for UT
Table 8a - Examination and Testing of Test Pieces Destructive Test Requirements
Butt Welds Transverse Tensile Test
Transverse Bend Test
Impact Test (Charpy)
Hardness Test (Vickers)
Macro-examination
2 specimens
1 Root and 1 Face
specimens
1 Set of 3
1 specimen
1 specimen
Impact tests are only
required in the root
area for all material
thicknesses more than
12 mm and side bends
to be performed
T-Butt Joints Hardness Test (Vickers)
Macro-examination
1 specimen
1 specimen
Fillet Welds Hardness Test (Vickers)
Macro-examination
Fracture Fillet Test
1 specimen
2 specimen
1 specimen
Other Welds Hardness Test (Vickers)
Macro-examination
1 specimen
1 specimen
Other tests may be
required by Company,
Note: All destructive testing shall only be carried out in a Company approved testing
laboratory. A Company representative shall witness all destructive testing at all times.
Both plate and pipe require separate weld qualifications, except for plate to pipe fillet
welds which are covered by a fillet weld qualification as per Table 10.

Welding Positions
In all cases when impact tests are not required the position of the test weld qualifies for all welding
positions (both pipe and plate). When impact tests are required; a test piece carried out in the
vertical up position will only be qualified for vertical up welding. All other positions can be qualified
in one welding position (both pipe and plate).
Joint Configuration
For test pieces welded from one side only, this also qualifies joints to be welded from both sides.
Test pieces welded from both sides does not qualify joints to be welded from one side only. (both
plate and pipe).
For test pieces welded without backing, this also qualifies joints to be welded with backing. Test
pieces welded with backing does not qualify joints to be made without backing.
Butt, T-Butt, fillet and any other joint configurations require separate qualifications.
T Butts also qualify fillet welds within the range.
Location and Cutting of Test Specimens
All test specimens shall be either thermally or mechanically cut; if thermal cutting is to be used at
least 3 mm from the cut edge must be removed by mechanical means. The location of test
specimens shall be in accordance with the company requirements. The dimensions of the test
specimens shall be in accordance with this document.
Test specimens shall only be taken after NDT has been conducted and accepted, it is permitted to
take a test specimen in an area free from any known acceptable imperfections detected by NDT,
but these areas must be kept as close as possible to the Company requirements.
Impact Testing (Charpy V-notch)
When impact tests are required, the minimum average value of impact energy and minimum
individual values of impact energy for each group of three impact tests shall not be less than the
values given in table 9; this is applicable for both welding procedure and repair welding procedure
approval. The test temperature shall be the minimum design temperature. This is normally 0°
C for
any structure to be installed underground, and -10°
C for all structures operating in an outdoor
environment. High strength materials and materials with a greater thickness than 50 mm may
require lower temperatures, if required these temperatures will be specified by Company. The
number of sets of impact tests shall be in accordance with table 4 as of this document, the impact
specimens shall be machined transverse to the weld and positioned within 2 mm of the root and
2 mm of the cap surface with the notch located in the vertical centre of the weld.
The dimensions of the test specimens shall be as in accordance with table.
Note: V-notch 2 mm in depth, notch radius 0.25 mm, 45° included angle.
Table 9 - Impact Energy Values
Material
Thickness mm
Charpy V-Notch
specimen size mm
Charpy energy (Joules)
Min. average
value
Min. individual value
> 6.5 to < 10 10 x 5 29 17
> 10 to < 12.5 10 x 8 33 20
> 12.5 10 x 10 40 30
Tensile Testing
When tensile testing is required, the tensile strength of the weld zone of each specimen shall be
equal to or not greater than 20% of that specified for the minimum tensile strength of the parent
material. If the specimen breaks in the weld metal it shall be considered acceptable providing it
meets the requirements as stated above.

3 mm
3 mm
3 mm
3 mm
If the specimen breaks in the parent material (outside the weld zone) it shall be considered
acceptable providing the tensile strength is not less than 90% of the specified tensile strength of
the parent material. If none of the above can be achieved the specimen shall be considered a
failure.
• For parent material thicknesses < 12 mm the tensile test specimen shall be ground smooth
(excess weld metal removed).
• For material thicknesses ≥ 25 mm, excess weld metal may be left undressed.
• Test specimen dimensions: length 240 mm, width 25 mm, full material thickness.
Macro-Examination
When required, macro specimens shall be cut transvers to the weld and shall be free from cracks
and lack of fusion; all other defects shall be in accordance with section 6 of this document. Macro
specimens shall be full thickness and cut in such a way as to include weld metal, HAZ and shall
include unaffected parent material. The macro specimen shall be cut, polished to P 400 grit paper,
etched and viewed under x5 magnification.
Note: Mirco specimens shall be required on certain Aluminium grades
Hardness Testing
Marco specimens shall be used for the hardness testing, the hardness specimens shall be tested
under a 10 Kg load, unless a load less is required for test welds with a narrow HAZ, a change in
load will require company approval. The hardness impressions in the hardness test specimen shall
be made in accordance with figure 1. The hardness test shall be acceptable providing it meets
the requirements of table 6.
Figure 1 - Locations for Hardness Testing

Fillet Fracture Test
When required fillet weld fracture tests shall be made with a minimum fillet weld size to be used
in construction (minimum of two passes), fillet weld sizes to be in accordance with this document
see section 5 for more details. Acceptance of the fracture fillet test shall be in accordance with
section 6 of this document.
Test specimen dimensions: Two plates in a Tee configuration 150 mm x 70 mm.
Bend Test
When required a face bend and root bend shall be carried out, for materials over 10 mm thickness,
a side bend test shall be carried out. Both the cap and root pass shall be as welded. Any
indication/rupture on the surface under tension exceeding 2 mm shall be considered unacceptable.
Test specimens shall be a minimum of 300 mm in length, 25 mm width.
Note: The bending machine former diameter shall be 4 x material thickness.
Qualification of Welders
General
All welders shall be qualified by conducting a Company approved welder qualification test.
Welder qualification tests shall be conducted in accordance with the applicable approved WPS and
witnessed by Company inspector, Contractors inspector and third party inspector is applicable.
The welder qualification test shall meet the requirements of this document.
Contractor may submit evidence of a welder’s previous qualification for Company approval; no
previously qualified welders are permitted to conduct any production welding without Company
approval.
Contractor shall have qualification certificates for each qualified welder on file available for
Company review. An up to date register shall be maintained of all qualified piping and structural
welders.
The register shall include the following:
• Welders name and identifying number
• Welding process and position for which each welder is qualified
• Date of qualification (Test date)
• WPS for which each welder is qualified.
Examination and Testing
Each test piece shall be marked with a permanent marker (paint stick), the welder’s identification
number and test date; if the testing is to be done independently the examination body shall be
included.
All qualification tests shall undergo visual and none destructive testing in accordance with this
document. Destructive tests shall only be carried out on fillet welds in accordance with this
document.
Note: A welder who conducted the WPQR shall automatically qualify in the process,
position and material qualified in the WPQR( assuming all the requirements are met)
Essential Variables and Range of Approval.
The qualification range of approval for each welder shall be in accordance with this document, and
any changes in the WPS, which is considered harder to weld than the welder is qualified for,shall

undergo a new qualification test, the welder shall only be qualified on the product type of the test
piece (plate or pipe).
The qualification range of each welder shall be as follows:
Table 10 – Essential Variables
Variables-Essential Changes affecting approval
Welding process 1. Welder is qualified only in the process, which was used in the
qualification tests. However 136 qualifies 135 also within the
same range of approval
2. Separate qualifications in various processes, qualifies for their
combinations also.
Material specification 1. Any change in material group except that
a. Qualification in group 3 qualifies group 1
b. Qualification in group 5 (Q&T steel) qualifies group 1
Material thickness 1. T≤5mm qualifies T to 2T in mm
2. T>5mm but ≤15mm qualifies 5mm to 2T in mm
3. T>15mm qualifies all thicknesses
Plate-Pipe-others 1. Plate qualifies only plate
2. Pipe qualifies plate, pipe and also plate to pipe joints
3. For all other components, joints separate qualification is
necessary
Joint configuration 1. Change from fillet to butt
2. Deletion of a backing strip
Filler metal type 1. Change from rutile to LH type electrode
2. Change from cellulosic to other types or vice versa
3. Change from fused flux to agglomerated flux or vice versa
4. Cellulosic electrode qualifies only that type
5. Low hydrogen electrode qualifies rutile electrodes also
6. Solid wire qualifies metal cored but not flux cored
7. Flux cored qualifies only flux cored
Filler metal diameter 1. Any change in diameter of the electrode, filler wire by more
than 50% for the root run
Shielding gas and
flow rate
1. Change from active gas to inert gas or vice versa
2. Any increase or decrease in gas flow rate by more than 50%
Shielding flux 1. Change from fused flux to agglomerated flux or vice versa
Electrical
characteristics
1. Any change in type of current or polarity
Welding position 1. Any change in position beyond that permitted by Table 11
Direction of welding 1. Change from PF to PG
2. Change from HLO45 to JLO45
3. Qualification in PF,PG, HL045, JL045 qualifies to that position
only
Time lapse between 1. Beyond that is permitted by the WPS

Preheating 1. Changes beyond that is permitted by WPS
2. Change in the method of preheating
Interpass
temperature
1. Any change beyond that is permitted by the WPS
Post Weld heat
treatment
1. Any change beyond that is permitted by WPS
Welding parameters 1. Any change beyond that is permitted by the WPS
Pipe diameter 1. Test pipe diameter (d) less than 10 mm qualifies only (d)
2. Test pipe diameter (d) more than 10mm but less than 75 mm
qualifies from (d) to (2d)
3. Test pipe diameter (d) more than 75 mm qualifies all pipe
diameters above 75 mm.
Techniques 1. Change from one of the following modes to another
a. Manual
b. Semi-automatic
c. Automatic
d. Mechanized
e. Robotic
Each mode qualifies to that mode only.
2. Addition or deletion of any sequencing techniques like back-
step, skip etc.
3. Change in the metal transfer mode in MIG/MAG process
4. Single wire to multi wire and vice versa in SAW process
5. Change to autogenous welding or vice versa in TIG
6. Change to pulsing and vice versa in MIG/MAG/FCAW/TIG
process
7. Change from single layer to multi-layer welding; Multi-layer
qualifies single layer but not vice versa.
Re Tests
If the qualification test piece fails in accordance with the requirements of this document, the welder
shall conduct a new test piece, if the welder fails a second time the welder shall be regarded as
incapable of welding in accordance with the approved WPS. In both cases if the failure is due to
faulty welding equipment or any other reason other than welder skill a retest shall be permitted.
Period of Validity
A qualified welder shall remain qualified within the range of approval for the duration of the
project/contract providing, the welder has been working in accordance with the qualification WPS
for within every six months.
If the welder hasn’t been working in accordance with the qualification WPS for over six months,
the welder is required to conduct a new qualification test weld.
Welding Position Qualification Range.
All welding qualification ranges shall be in accordance with Table 11 of this document. All fillet
welds require a separate qualification test.

Table 11 - Welding Position Qualification Range
Welding position of
test piece
Positions qualified for butt welds
only
Positions qualified for
fillet welds only
PA PA only PA only
PB N/A PA, PB
PC PA, PB, PC PA, PB, PC
PD N/A PA, PB, PC, PD
PE PA, PC, PE N/A
PF PA, PC, PE, PF PA, PB, PC, PD, PF
PG PG only PG only
H-LO45 (pipe only) PA, PC, PE, PF, H-LO45 N/A
J-LO45 (pipe only) PG, J-LO45 N/A
Tests to be Conducted
The following tests shall be conducted for welder qualification
Table 12 - Welding Qualification Tests
Type of test Butt welds Pipe and Plate Fillet welds Other welds
Bend test- BS EN
ISO 5173
2 side bends for T>12mm
1 Face and 1 Root for
T,12mm
Not required As per requirement
Radiography- BS
EN ISO 17636-1
Yes. But not required if
bend tests are done
Not required --do--

Macro
examination
under 10X-
Not required except in
case of welds made with
combination of processes
One sample to be
taken from start
stop position and
examined
--do--
Fillet fracture
test- BS EN ISO
9017
Not applicable One sample to be
taken from start
stop position
--do--
Post Weld Heat Treatment (PWHT)
General
PWHT shall be carried out for the purpose of stress relieving and hydrogen release. PWHT shall
only be carried in accordance with the approved procedures and only when approved by the
Company. All PWHT treatments shall be carried out in a controlled manner either by the use of a
furnace or as an alternative by the use of heating blankets. When PWHT is to be carried out by
the use of a furnace, the component shall be placed centrally in the furnace as to ensure a uniform
heating throughout the components thickness (at the time the component is placed into the
furnace, the furnace temperature shall be no less than 50°
C and no greater than 280°
C).
When heating blankets are to be used, the heating blankets shall be placed in such a way as to
ensure a uniform heating of the component and the temperature variation throughout the
component is no greater than 75°
C.
Note: Localised PWHT shall not be carried out under any circumstances. In all cases the
PWHT temperature shall be maintained throughout the components thickness.
Temperature Measurement
All temperature measurements shall be monitored by the use of thermocouples and multipoint
temperature recorder’s. A minimum of three thermocouples shall be used and placed in such a
way as to ensure uniform heating throughout the component, no thermocouple reading shall be
more than 30o
C apart throughout the PWHT heating cycle. All measuring devices being used shall
have a valid certificate of calibration (all calibration certificates shall be checked by the Company
Inspector before the PWHT process is carried out). All temperature recorders shall be checked by
the Company’s inspector to ensure the speed of the chart being used matches that of the
temperature recorder.
Note: The method of thermocouple attachment shall be approved by the Company prior
to the commencement of PWHT.
Temperatures and Heating/Cooling Rates
Where dissimilar thicknesses exist, the thicker member shall be taken as the material thickness).
C/Mn steels
• Maximum PWHT temperature 650o
C, minimum PWHT temperature 580°
C
• Material thicknesses > 25 mm, soaking time 1 hour per 25 mm of material thickness.
≤ 25 mm, soaking time 45 minutes per 25 mm material thickness.
• Heating rates; above 320°
C (controlled heating) the heating rate shall be 5000°
C divided
by the maximum material thickness, but no greater than 220°
C per hour.
• Cooling rates shall be the same as the heating rates to a temperature of 320°
C (controlled
cooling rate).
Quenched and Tempered Steels
• When required the PWHT temperatures shall be the same as for C/Mn steels except the
maximum PWHT temperature shall not exceed 600°
C, heating rates shall be controlled
from 300°
C, cooling rates shall be controlled to 300°
C
• Insulation and thermocouples shall not be removed until the component’s temperature
has dropped to below 110°
C

Austenitic and Duplex Stainless Steels
• When require the PWHT shall be the same as for QT Steels except the maximum PWHT
temperature shall not exceed 450o
C.
Note: In all cases thermocouples and insulation shall not be removed until the
component’s temperature has dropped below 110o
C
Reports and Records
All PWHT charts shall be reviewed by all parties, Company, Contractor and where applicable third
party QC. The PWHT charts shall be filed in the Contractors QA/QC department and shall be made
available for review at any time if required.
Note: No stress reliving shall be carried out until all welding has been completed
(including any repairs).
Note: Full Inspection to be carried out after all PWHT has been conducted in accordance
with the initial inspection requirements of this document.
Hydrostatic Testing
General
All process piping shall be subjected to a hydrostatic testing in accordance with the approved
procedure. Test pressure shall be in accordance with the approved procedure and Company
requirement’s, the test pressures shall be based on operating pressure, material type and service
conditions of the pipe to be tested, the test pressures shall not be less than 1.5 times that of the
systems operating pressure (design pressure). The Contractor shall be responsible for all safety
and environmental requirements. All temperature and pressure measuring devices shall have a
current/valid certificate of calibration, all pressure and temperatures shall be plotted on a
temperature/pressure chart.
Note: All hydrostatic testing operations shall be witnessed by Company Inspectors.
Test Preparation
All water used for hydro testing shall be clean, non-corrosive and free from dissolved solids, water
temperature shall be no less than 10o
C. The Contractor shall add a non-hazardous, non-corrosive
corrosion inhibitor to the water to be used for hydro testing. In the case of Austenitic and Duplex
stainless steels, the water used shall not have chloride contents greater than 45 PPM. Hydrostatic
testing shall be carried out with installed valves in the half open position, under no circumstances
shall hydrostatic testing be carried out with valves in the fully closed position in the isolation
system.
Flushing
All piping to be hydrostatic tested shall be thoroughly cleaned by water flushing, the piping shall
be flushed from the high point to the low point where applicable. Where multiple high point exist
multiple flushing points shall be used, the flushing pressure shall be sufficient as to remove all
sediments and debris. All instruments (not required for the hydrostatic testing) shall be removed
before the commencement of testing as to avoid damage to the instruments. All valves during the
flushing operation shall be in the fully open position and flushing shall continue until clean flushing
medium appears at all discharge points.
Note: The Contractor shall be responsible for the disposal of all flushing media in
accordance with the local environmental regulations.
Conducting the Test
• Examine all connections in the system prior to the test as to ensure correct tightness.

• Isolate any equipment that may be damaged by the test, these isolation points shall be
recorded on the test report.
• All valves shall be in the half open position and against flanged or plugged connections.
• The piping shall be slowly filled with water until all air is excluded. Once all air is excluded
the hydrostatic vents shall be closed.
• The piping shall be slowly pressurized until 50% of the test pressure is reached; once
this pressure is reached the pressure shall be held at this point for no less than 15
minutes. During this hold time the pipe system shall be checked for any leaks, if leaks
are detected the pressure shall be dropped to half this pressure before any leaks can be
rectified.
• After the hold time at 50% of the test pressure has elapsed the pressure shall then be
raised to the test pressure in increments until the test pressure is reached (the number
of increments and the test pressure increases to be approved by Company. If any leaks
are detected, the pressure shall be dropped to a pressure no greater than the pressure
at the last increment before any leaks are rectified.
• Once the test pressure has been reached the test shall not start until temperatures have
equalized through the piping system under test and transit strains have dissipated. A
test start time shall be approved by Company Inspector and recorded
• The test duration shall be no less than 2 hours (greater test durations may be required
as to Company requirements).
Note: No testing shall be conducted during periods of rain, unless the entire piping
system is protected from the weather. No testing shall be carried out at temperatures
below 10o
C
Note: Disposal of all hydrostatic testing medium shall be the responsibility of the
contractor and shall be in accordance with local environmental regulations.
Inspection
The piping system under test shall be inspected for any leaks and other problems during and at
the end of the test duration. For the test to be considered acceptable, no leaks shall be detected.
Reports and Records
The piping pressurization steps, test temperature at the start time, hold periods and finish time
shall be recorded on a chart recorder. All test reports shall be submitted to the Company for
approval.
Each pressure test shall be given a unique test number; the number shall be referenced on the
front sheet of the pressure test pack. A pressure test pack shall be produced for each pressure
test. If the hydrostatic test fails then no test chart shall be signed off. The Contractor shall be
responsible for all remedial work, repairs and retesting. No piping shall be accepted unless covered
by a fully signed off hydrostatic test chart.
Pneumatic Testing
General
Only low pressure piping systems shall be considered for pneumatic testing and each test shall
only be carried out with written approval from the Company and in accordance with the approved
procedure. Test pressure shall be in accordance with the approved procedure and Company
requirement’s, the test pressures shall be based on operating pressure, material type and service
conditions of the pipe to be tested. The Contractor shall be responsible for all safety requirements.
An area of at least 4 meters away from the test area shall enclosed as to prevent any unauthorized
personnel from entering the test area, this shall be done as to Company requirements. All
temperature and pressure measuring devices shall have a current/valid certificate of calibration,
all pressure and temperatures shall be plotted on a temperature/pressure chart.

Note: All safety precautions shall be approved by the Company’s safety representative
before any pneumatic testing is carried out.
Test Preparation
All instruments, equipment shall be prepared the same as for hydrostatic testing. The exception
to this is that all flanges, plugged ends shall be wrapped in duck-tape, with a hole punched in the
top of either the flange or plugged end. The piping shall be pressurized to a pressure of 25 psi
with clean dry air, any gross leaks shall be rectified.
Conducting the Test
• The piping shall be slowly pressurized to 50% of the test pressure and held for a minimum
of 20 minutes at this pressure, a check shall be made for any leaks using a soap solution
swabbed on all joints, connections and welds. Any leaks detected shall be rectified at a
pressure less than 10% of the test pressure.
• After any possible leaks have been rectified the pressure shall then be increased in
increments of 10% until the test pressure is reached. When leaks are found during this
period, the pressure shall be reduced to below 50% of the test pressure before and
rectification of the leaks can be conducted. Where the leaks cannot be rectified, this may
require the piping system to be depressurized and stripped down.
• Once the test pressure has been reached the test shall not start until temperatures have
equalized through the piping system under test and transit strains have dissipated. A test
start time shall be approved by Company Inspector and recorded
• The piping system under test shall be carefully inspected for any leaks and/or other
problems at the end of the test period and at the test pressure. All joints, connections and
welds shall be swabbed with a soup solution. Test duration at the test pressure shall be a
minimum period of two hours.
Note: No testing shall be conducted during periods of rain, unless the entire piping
system is protected from the weather. No testing shall be carried out at temperatures
below 30o
C
Inspection
The piping system under test shall be carefully inspected for any leaks and/or other problems at
the end of the test period and at the test pressure. All joints, connections and welds shall be
swabbed with a soap solution. Test duration at the test pressure shall be a minimum period of two
hours. The test shall be considered acceptable if no leaks are detected.
Reports and Records
The piping pressurization steps, test temperature at the start time, hold periods and finish time
shall be recorded on a chart recorder. All test reports shall be submitted to the Company for
approval.
Each pressure test shall be given a unique test number; the number shall be referenced on the
front sheet of the pressure test pack. A pressure test pack shall be produced for each pressure
test. If the pneumatic test fails then no test chart shall be signed off. The Contractor shall be
responsible for all remedial work, repairs and retesting. No piping shall be accepted unless covered
by a fully signed off hydrostatic test chart.

Coatings for Structures and Piping
General
Contractor shall be responsible for the correct storage of all materials required for surface
preparation and coating materials, all storage of coating materials shall be in accordance with the
manufactures and Company requirements. The Contractor shall be responsible for the disposal of
all waste materials; the disposal shall be conducted in accordance with local environmental
regulations. Surface preparation and the application of all coatings shall be conducted in adequate
ventilation areas, if this can’t be achieved then all personnel conducting these operations shall be
issued with suitable PPE as to comply with local safety regulations. All coatings and surface
abrasives shall be free from lead, chromate and crystal silica. In addition all coating materials shall
comply with the latest guidelines with respect to VOC’s. All surface preparation, mixing, application
and curing of the coating system shall comply with the requirements of the manufacturer’s data
sheets and the requirements of this document.
Surface Preparation
Unless otherwise approved by the Company, all stages of fabrication and welding, any applicable
PWHT and inspection (including NDT) shall be completed before surface preparation begins.
All gaskets, flanges, valves, nameplates, instrumentation, gauges, electrical components etc. shall
be suitably protected; Company shall approve all protection. All sharp edges, surface pitting,
surface imperfections etc. shall be ground smooth in accordance with the Company requirements.
All oil and grease contaminations shall be removed by solvent cleaning prior to abrasive blasting.
All blasting shall be performed using a dry blasting technique. The blasting material shall be either
garnet or copper slag; no recycling of copper slag shall be permitted. The recycling of garnet may
be permitted up to a maximum of two times, but only by written approval of the Company.
The surface preparation shall be blasted to Sa 2 ½ unless otherwise specified by the coatings
manufacturer or approved by the Company. All surface profiles shall be in accordance with the
manufacturers date sheets and shall be measured by the use of a dial micrometre type gauges
with the testex tape attached to the final paint report, the final anchor pattern shall be typically
1.5 to 2.0 mils peak to peak.
No blasting operations shall be conducted if any of the conditions below exist.
• 90% RH value
• When the steel temperature is less than 3ºC above the dew point (dew points shall be
measured by the use of a whirling psychrometer)
• During night time hours, dusk to dawn. If blasting is allowed by Company approval during
night-time hours, the surface shall be swept clean the next morning to provide a near
white blast surface.
After blasting all abrasives, dust etc. shall be removed from all surfaces to be coated.
Note: No acid washes or other cleaning solutions or solvents shall be carried out after
blasting has been carried out
Note: No silica (sand) based materials or materials containing impurities shall be used
for blasting.
Coating Application
All coatings application shall be conducted in accordance with this document and the coating
manufacturer’s recommendation. No coatings application is to be conducted until Company
representative has approved the surface preparation.
All coating materials shall not exceed the manufacturer’s pot life and only sufficient volumes for
the appropriate pot life of the application mixed at one time. All mixing of the paint shall be
conducted in accordance with the coatings recommendations, mixing shall be conducted in clean

containers free from grease other paints and any other contaminations, all containers shall be
covered to prevent contamination from dust, dirt and rain. When zinc-coating systems are to be
applied, the zinc coating shall be continually agitated during application.
No coatings application shall be conducted if the following exist.
• In fog or rain or when the steel substrate is damp or wet.
• When the steel surface temperature is less than 3o
C above the dew point temperature as
measured by a sling psychrometer.
• RH% > 90%.
• The temperature is < 10o
C and greater than 45o
C.
• At night time hours (24 hour coatings application is permitted providing it is conductedin
doors and with written Company approval).
• In direct wind speeds > 15 miles per hour (unless written approved by Company
representative).
• Inorganic zinc coatings require a minimum RH value of 50%.
All blasted cleaned surfaces shall be coated with a primer during the same day as the blasting
occurs or before any visible signs of rusting occurs. Material surfaces shall be clean, dry and free
from dust before any coating application can be conducted. All coatings applications shall be
applied by spray methods and in accordance with the manufactures recommendations and by
company approval, all atomizing air and paint pot pressures shall be in accordance with the
manufacturers recommendations and by company approval. An adequate moisture trap shall be
placed between the air supply and the pressure feed gun. Separate regulators shall be used to
adjust the paint pressure and atomization pressure; all regulators shall be calibrated and shall be
fully functional at all times. WFT, DFT, curing times shall be in accordance with the manufactures
data sheets, no application of the next coat shall be applied until the correct WFT, DFT and curing
times have been established. A brushed stipe coat shall be applied to all welds prior to the
application of each coat of the paint system.
Note: Coatings may be applied by brush application in areas which can’t be properly
spray coated (shadow areas)
Note: Inorganic zinc coatings shall not be applied by brush in any circumstances.
Note: All coats applied of the coating system shall be from the same manufacturer.
Inspection
Company inspector shall inspect all coatings. All coated surfaces shall be free from pinholes,
sagging (excessive coating build-up), wrinkling, blistering, bittiness (dust or dirt inclusions),
inadequate coating thicknesses, insufficient curing times and any other coating defect which is
considered detrimental to the coating systems effectiveness. All rejected work shall be fully
removed by blasting and reapplied. All repaired areas shall be feather edged up to the adjacent
edges of the original coating system and repaired in accordance with the requirements of this
document and in accordance with the manufactures recommendation. All accepted work must be
free from abrasions and uniform in colour and appearance. Both the Company and manufacturers’
representatives can only make final acceptance of the coating system.
Repair of Damaged Areas (touch-up)
All external surfaces where coating is damaged during fabrication, erection or transportation shall
be repaired. Care shall be taken to avoid damaging the coating of the surrounding areas of the
repaired and to ensure complete tie-in of the repaired coating with the coating of the surrounding
area.
Top coat damage, base coat undamaged:
Damaged coating to be removed by sand paper or other alternative means (wire brushing shall
not be used), at least 50 mm from the edge and chamfered back on to the top coats adjacent

surfaces (feather edge). Apply by spray method the layer of finish coat (top coat) to obtain the
required coating thickness.
Coating damage to base metal
Repair the area by blasting, Sa 2 ½ near white metal over a distance of no less than 100 mm from
the damaged area, feather edge all adjoining paint surfaces with sand paper to provide a smooth
surface transition and apply the same coating system in accordance with this document until the
required coating thickness is obtained.
Reports and Records
A report shall be produced by the Contractor and submitted to the Company for all coating systems
applied. The coating report shall include as a minimum the following:
• Paint system number
• Items coated
• All environmental conditions: Steel temperature, RH%, Dew point temperatures, prior to
blasting
• Surface preparation: blasting grade, surface profile (measured by profile dial micrometre,
textest tape allied to the report for permanent record), abrasive used (any applicable re-
cycling)
• Painting application: WFT, DFT, method of application.
• Visual inspection: any coating defects
• If applicable repairs
Protection and Preservation
General
Protection on site of all materials, equipment, structures and piping shall be the responsibility of
the Contractor
Either end caps, or redundant valves shall blank off all open-ended spool pieces. Any open-ended
threaded connections shall be plugged or capped after coating with a grease base rust preventive.
All process piping and vessels shall be preserved internally by purging with Nitrogen, after purging
the piping or vessels shall be left pressurized with Nitrogen at 5 to 10 psi, the pressure shall be
monitored and topped up with Nitrogen if required. All other uncoated structural materials shall
be protected against corrosion by fogging (light spray coating of grease based rust inhibitor. All
piping, equipment and other structures shall only be stored off the ground on a suitable material,
eg wooded blocks of a suitable thickness

FIGURE 2 - Detail for Weld Preparation
Root Gap and Root Faces May Vary Depending on Welding Process,
Material Type and Thickness, refer to the WPS for further details.
30o
+5o
-0o
Weld Preparation for Joints in the Flat (PA), Vertical (PF/PG) and
Overhead (PD/H-LO 45) Welding Positions for both single and double
sided bevels. Other joint preparations may be considered for
mechanized welding processes.
+5o
30o
-0o

FIGURE 3 - Detail for Weld Preparation
Weld Preparation for Joints in the Horizontal/Vertical (PC) Welding Position for
both single and double sided bevels. Other joint preparations may be considered
for mechanized welding processes
15o
+5o
-0o
Root Gap and Root Faces May Vary Depending on Welding Process, Material
Type and Thickness, refer to the WPS for further details.
+5o
45o
-0o

FIGURE 4 – Ultrasonic Joint Configuration
T Butt Weld - Full Penetration T Butt Weld - Partial Penetration
Cruciform Butt Weld - Full Penetration Cruciform Butt Weld - Partial Penetration
Butt Weld - Set-Through (Including
Nozzles)
Butt Weld - Set-On (Including Nozzles)

Copyright
TWI UK Ltd holds and reserves the rights for all copying of this document. No unauthorized copying
of this document in any form or by any means – electronic, photocopying, and recording or by any
other processes without prior documented permission from TWI UK Ltd or any TWI subsidiary
Companies.
This document is intended to be used in conjunction with the CSWIP examinations, under no
circumstances shall this document be used for any other purpose other than examinations.
TWI Training & Examination Services
TWI Ltd, Granta Park
Great Abington, Cambridge
CB21 6AL
United Kingdom
Copyright: ©2014 TWI Ltd. All rights reserved

Cswip 3.2 spec converted

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