General welding, fabrication and inspection table of contents page

Polaris 

Engineering 

Standard 

140.10 

Rev.: 0 

Page: 1 of 24 

Date: 07/06/09 

GENERAL WELDING, FABRICATION AND INSPECTION 

TABLE OF CONTENTS 

PAGE 

I. SCOPE 2 

II. REFERENCES 2 

III. WELDING PROCEDURES 3 

IV. WELDING PROCESSES (GENERAL) 4 

V. WELDING PROCESS LIMITATIONS 5 

VI. FILLER MATERIALS AND FLUXES 6 

VII. WELD JOINT PREPARATION AND WELDING FABRICATION 9 

VIII. PREHEAT AND INTERPASS TEMPERATURES 13 

IX. POSTWELD HEAT TREATMENT 14 

X. NON-DESTRUCTIVE EXAMINATION, TESTING AND INSPECTION 17 

XI. REPAIRS 20 

XII. SUMMARY OF WELDING VARIABLE LIMITATIONS, 21 

RESTRICTIONS AND OTHER REQUIREMENTS 

XIII. 

PROCEDURE FOR REVIEW AND ACCEPTANCE OF 

VENDOR WELDING PROCEDURES 22 

APPENDIX I - WELD MAP 24

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Engineering 


140.10 

Rev.: 5 


GENERAL WELDING, FABRICATION AND INSPECTION 

I. SCOPE 

A. This Standard covers the minimum welding requirements, for welding of shop 

and field fabrications and the weld inspection of the following: 

1. Pressure containing equipment and piping, whether code stamped or not, 

including but not limited to: rotating equipment, boilers, pressure vessels, 

heat exchangers, air coolers, shop and field fabricated piping, fired heater 

tubes, storage tanks, stacks and their attachments. 

2. Equipment or piping containing toxic or corrosive materials. 

3. Structural Steel 

4. Other fabrications where specified. 

B. This Standard modifies the requirements of applicable ASME, AWS, API and 

ANSI codes and standards in effect at the revision date. 

C. Conflicts between requirements of this Standard, related specifications, standards, 

codes, purchase orders or drawings shall be clarified with Client or Client's 

Engineer (designated Contractor) prior to proceeding with the fabrication of the 

affected parts. Regarding conflicts, the Client reserves the right of final decision. 

D. Where conflicts exist between this Engineering Standard and other POLARIS 

Engineering Standards and/or applicable codes or regulations, the more stringent 

requirement shall govern. All conflicts shall be brought to the Client’s attention 

for resolution. The Client shall be the sole arbiter of any conflicts. 

II. 

REFERENCES 

This POLARIS Standard is to be used in conjunction with the latest revision of the 

standards and codes listed below, unless specifically noted. The terminology "latest 

revision" shall be interpreted as the revision in effect at the time of contract award. This 

POLARIS Standard may reference specific sections of some of these codes and 

standards. The revision of the codes and standards being referenced is noted below in 

parenthesis. This information is provided to identify the subject matter being referenced. 

Changes or exceptions made to the referenced code or standard shall apply to later 

revisions as applicable. 

A. POLARIS Engineering Standards

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3. 840.1 General Requirements For Pipe Fabrication 

B. National Codes and Standards 

1. API American Petroleum Institute Standards 

2. AWS American Welding Society Standards 

3. ASME B16.5 Pipe Flanges and Fittings (1998) 

4. ASME B31.1 Power Piping (2001) 

5. ASME B31.3 Process Piping (2001) 

6. National Board Inspection Code (NBIC) 

7. ASME Boiler and Pressure Vessel Code (2001) 

III. 

WELDING PROCEDURES 

A. Welding procedure specifications (WPS) and procedure qualification test records 

(PQR) for Vendor welding covered by this Standard shall be submitted to the 

Client or the Client's Engineer for review and acceptance prior to the start of any 

welding. No welding shall commence until welding procedure specifications and 

qualification records have been accepted by Client or Client’s representative. 

B. Welding performed by Subvendors is also required to go through the same review 

and acceptance procedures described in III.A above. Vendors are required to 

provide copies of this and all other relevant standards to their Subvendors and to 

review their Subvendors welding procedures for conformance to this Standard 

prior to submitting to the Client or Client's Engineer for acceptance. 

C. The information contained in the welding procedure specifications and procedure 

qualification test records shall include, but not be limited to the information 

contained in ASME Code, Section IX and AWS D1.1. Welding procedure 

specifications shall conform to ASME Section IX, Form QW-482 or equivalent. 

Procedure qualification records shall conform to ASME Section IX, Form QW- 

483 or equivalent. Structural steel welding procedures may conform to AWS 

Prequalified or AWS Recommended Procedure formats.

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D. This Standard includes additional requirements and restrictions, which may not be 

listed in the Vendor's submitted welding procedures. They shall be listed, when 

required by this Standard, either in the welding procedure or on the weld map. 

The main additional requirements are summarized in Section XII below. 

E. Vendor shall prepare a “Weld Map Form" as illustrated in Appendix I of this 

Standard which must be completed and submitted at the same time as welding 

procedures for Client's acceptance. Vendor may submit this information in other 

formats provided all information required in Appendix I is included. 

F. All welders shall be qualified by means of welding performance testing. Welding 

performance qualification test records shall be made available for review by the 

Client or Client's Representative upon request. Welding performance tests shall 

be in accordance with ASME Section IX or AWS D1.1 as applicable, under 

conditions of restraint and accessibility as demanding as those to be experienced 

in production by the welder. Welding performance test records shall conform to 

ASME Section IX, Form QW-484 or equivalent. Welding performance testing 

records for structural steel shall conform to the recommended AWS format. 

G. Weld overlay or clad back-welding shall be qualified in accordance with ASME 

Section IX. 

H. Weld overlaying or clad restoring (back-cladding) shall be applied with a 

minimum of two passes and capable of controlling dilution as evidenced by a 

chemical analysis. Depth of chemical analysis shall be three-quarters of the 

required overlay thickness unless specified otherwise and approved by Client. 

I. When impact testing is required by the code or POLARIS Standards, impact test 

results for weld and heat affected zone shall be reported with the welding 

procedure qualifications. 

J. When maximum Brinell hardness is specified by code, POLARIS Engineering 

Standards, or Section X.D.8 of this Standard, they shall be reported with the 

welding procedure qualification record and they shall not exceed the maximum 

specified limits. 

IV. 

WELDING PROCESSES (GENERAL) 

A. The following welding processes are permitted, subject to the limitations set forth 

in Section V below, providing that satisfactory evidence is submitted showing that 

the procedures qualified are in accordance with applicable codes, standards, and 

this Standard. 

1. Manual shielded metal arc with covered electrode (SMAW) 

2. Gas tungsten arc: manual or automatic (GTAW)

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3. Automatic or machine submerged arc (SAW) 

4. Oxy – acetylene cutting (OFC-A) 

5. Gas metal arc (GMAW) 

6. Flux Core Arc Welding (FCAW) 

7. Plasma Arc Welding (PAW); manual, automatic or machine 

B. Welding processes other than those listed above require specific approval by the 

Client or Client's Engineer and shall not be assumed as acceptable by the Vendor 

during bid preparation. 

C. Fabricators and welders shall be capable of demonstrating satisfactory experience 

with the selected acceptable welding processes listed in this standard. First time 

use of a welding process requires specific written approval by Client prior to 

welding. 

D. Client and Client's Engineer reserve the right to disallow the use of any welding 

process or welder based on excessive rates of repair. 

V. WELDING PROCESS LIMITATIONS 

A. GMAW and FCAW processes shall have stated in the WPS, and on the required 

weld map (see Appendix I), whether the current is in the short circuiting arc or 

spray transfer range. The shop and the welding personnel shall have 

demonstrated production welding experience with each process to the satisfaction 

of the Client and Client's Engineer. 

B. GMAW is acceptable for root passes and completion of welds up to 3/8 inch 

deposited weld metal thickness for groove welds and 3/8” fillet weld size. When 

specific Client permission is obtained to exceed this maximum deposited 

thickness; all such welds shall be 100% ultrasonically shear-wave examined 

throughout their entire length. 

C. FCAW, in the short circuiting arc mode, is unacceptable. 

D. FCAW, spray transfer, without shielding gas, is acceptable with specific Client 

approval for structural steel welding fabrication only. 

E. FCAW, spray transfer, with shielding gas is acceptable for welding shop 

fabricated pipe and for welding pressure retaining parts of pressure vessels 

provided the following conditions are met: 

1. The procedure qualification record shall include results of micro hardness 

testing for both as-welded and stress relieved conditions as applicable for

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weld, heat affected zone, and base. 

2. Production NDE shall include 100% hardness testing on all FCAW 

weldments per Section X, Paragraph C. 

F. GMAW and FCAW for field fabrication must have the Client's specific approval. 

G. Automatic or machine type SAW is preferred. The SAW process shall have 

stated on the WPS that the procedure is automatic or machine type welding in 

order to be acceptable. Manual or semi-automatic SAW is prohibited. 

H. Automatic or machine type SAW of P-1 materials shall be limited to 1/2 inch 

maximum thickness per layer of deposit for material of 1-1/4 inch thickness or 

greater and 3/8 inch maximum thickness per layer of deposit for material less than 

1-1/4 inch thick. The maximum deposit for alloy and stainless steel shall be 

limited to 0.4 inches per pass. 

I. GTAW shall be utilized for pipe fabrication on first two layers for ferrous alloy, 

and non-ferrous alloys on single welded groove joints accessible for one side only 

and on other equipment as defined in the POLARIS Engineering Standards. 

GTAW shall be used on all piping buttwelds on P-1 materials 2” NPS and 

smaller. 

VI. 

FILLER MATERIALS AND FLUXES 

A. Filler materials and fluxes shall be as specified in ASME, Section II, Part C., 

Filler Materials and Fluxes, other than those specified in the above code and 

which meet other requirements of this Standard, shall not be assumed as 

acceptable by the Vendor during bid preparation. 

B. All welding shall employ a filler metal unless approved by the Client in writing. 

Welding employing no filler metal shall not be assumed as acceptable by the 

Vendor during bid preparation. Friction welding is prohibited. 

C. The specific AWS grade, ASME specifications, Manufacturer and trade name for 

filler metals and fluxes to be used on the project shall be indicated on the welding 

procedure specification and weld map (Appendix I). 

D. Use of filler metals and fluxes for other than the Manufacturer's primary 

recommended application is prohibited. For example: Filler wire intended for 

OFW shall not be used for GTAW. Filler wire intended for certain welding 

positions specified by the Manufacturer shall not be utilized in other welding 

positions. Fluxes recommended for single pass shall not be utilized on multi-pass 

welds. 

E. Automatic or machine submerged arc welding fluxes are subject to the following 

limitations:

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1. Fluxes used for welding carbon or low alloy steels shall not contribute 

alloying elements to the weld. 

2. The use of Lincoln 780 flux is prohibited. 

3. A separate welding procedure qualification shall be required for each 

brand and grade of flux and electrode combination. 

4. Welding procedures employing "active" fluxes for carbon steel shall 

demonstrate that hardness does not exceed 200 BHN. Hardness shall be 

reported with the procedure qualification record. 

5. Alloy steel shall be welded using an alloy wire and a "neutral" flux. Fluxes 

shall not contribute alloying elements to the weld deposit. 

F. Fluxes shall be reconditioned prior to re-use in accordance with Manufacturer's 

recommendations. The use of re-crushed slag is prohibited. 

G. Carbon steels of group P-1 shall be welded with A-1 analysis weld metal only. 

Use of other weld metal analysis numbers requires the Client's approval. 

H. For welding 70 KSI tensile strength P-1 material subject to a PWHT, filler metals 

containing 1/2% Mo are permitted in order to meet the minimum tensile strength 

requirement. 

I. Similar base materials shall be joined with a weld metal deposit that matches the 

base metal in both chemistry and mechanical properties. In cases where this 

cannot be accomplished, the Vendor shall propose a choice of filler together with 

the reasons for the choice for the Client's review and approval. 

J. Welds joining pressure containing parts of two different ferric steels shall have a 

weld metal deposit conforming to the nominal composition of the higher alloy 

base materials unless otherwise approved by the Client. 

K. Welds joining two different ferric steels, only one of which is a pressure retaining 

part, shall have a weld metal deposit conforming to the nominal composition of 

the pressure retaining part unless the engineering design specifies otherwise and 

written approval is given by the Client. 

L. When joining two different austenitic stainless steels, the (A-8) filler metal may 

match either and must result in a ferrite number range of 3-12. Delta ferrite shall 

be determined from the certified chemical analysis and the "WRC Delta Ferrite 

Diagram." 

M. Welds joining austenitic stainless steels to ferritic steels shall be made with filler 

metal as follows:

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1. Type 309 for design temperatures not exceeding 650 o F. 

2. Coated electrodes of SFA 5.11 AWS classes ENiCrFe-2 (comparable to 

Huntington Alloy's INCO A) and ENiCrFe-3 (comparable to Huntington 

Alloy's INCO 182) or bare electrodes of SFA 5.14 of AWS Classes 

ERNiCrFe-5 (comparable to Huntington Alloy's INCO 62) and ERNiCr-3 

(comparable to Huntington Alloy's INCO 82) except where process 

conditions do not permit. 

3. TP 310 fillers are acceptable only for welding of Type 310 base materials 

to themselves. 

N. For GMAW and GTAW welding of P-1 materials exceeding 65 KSI minimum 

tensile strength, only AWS classification ER70-S2 or ER70-S3, filler metals of 

SFA 5.18 shall be used. The use of ER70-SG & GS, ER-70C-G & GS of SFA 

5.18 is prohibited without prior submittal and approval of the filler metal material 

test reports (MTR’s) for each lot. Their utilization shall not be assumed as 

acceptable by the Vendor during bid preparation. When use of this material is 

approved by Client the material shall be marked and segregated for the job. 

O. For FCAW of carbon steels exceeding 65 KSI minimum tensile strength, only 

AWS Classification E7X-T1 or E7X-T5 filler metals of SFA 5.20 shall be used. 

P. Use of SMAW electrode groups F-1, F-2, and F-3 as specified in ASME Section 

IX, Table QW-432, are limited as follows: 

1. To fillet welds or butt welds on material not exceeding 65 KSI minimum 

tensile strength, in material thickness not exceeding 1/2 inch thickness. 

2. F-1, F-2, and F-3 electrodes are not permitted on materials requiring 

impact tests. 

3. F-1 or F-2 electrodes shall not be used for pressure retaining parts or nonpressure 

attachments to pressure retaining parts. 

4. F-3 electrodes may be used for root passes of butt welds regardless of base 

metal thickness. 

Q. The receipt, use, dispersal and retrieval of welding filler materials shall be 

maintained under strict control, with storage, baking and drying as recommended 

by the Manufacturer to assure that completed welds conform to the approved 

welding procedure specification requirements for welding materials.

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VII. 

WELD JOINT PREPARATION AND WELDING FABRICATION 

A. Joint designs shall be in accordance with applicable code or POLARIS 

Engineering Standard requirements. 

B. Weld joints shall be prepared by machining, grinding or thermal cutting. When 

thermal cutting is performed, the joint surfaces shall be ground to sound metal 

prior to welding. Materials shall be subjected to the same preheat requirements 

for thermal cutting as required by the applicable welding procedure. 

C. For austenitic material 2 inches and thicker, plate edges, including weld bevels 

shall be liquid penetrated tested. 

D. Welded butt joints shall meet the minimum requirements for penetration or fusion 

in accordance with the applicable code or POLARIS Engineering Standard 

requirements. 

E. The addition of permanent backing such as rings, bars, or strips are unacceptable 

and shall not be used without the Client's written approval. Their utilization shall 

not be assumed as acceptable by the Vendor during bid preparation. The 

additional backing referenced in this Standard is not defined by this Standard as 

the weld installed on the first side of a butt weld welded from both sides. 

F. Temporary (removable) backing rings, bars, or strips shall not be used without the 

Client's written approval. Their utilization shall not be assumed as acceptable by 

the Vendor during bid preparation. 

G. If approved by the Client, the weld area exposed when backing is removed shall 

be dressed and examined for cracks or defects by visual and liquid penetrated or 

magnetic particle examination methods, whichever is applicable. All backing 

material and unacceptable indications shall be removed completely and repaired 

utilizing a weld procedure which has been accepted by the Client. 

H. Materials of temporary backing rings, if approved by the Client, shall conform to 

the nominal chemistry of the weld filler metal as defined in Section VI of this 

Standard. 

I. When Client's approval is given for use of backing rings, the Vendor welding 

procedure and the weld map (Appendix I) submitted for review shall either 

indicate that welding was qualified with backing ring (state on PQR) or that 

backing ring will be added (stated on WPS and the weld map, Appendix I). 

J. Consumable inserts require written approval by the Client. Their utilization shall 

not be assumed as acceptable by the Vendor during bid preparation. If approved 

by Client, they shall in all cases conform to the nominal chemistry of the weld 

filler metal as defined in Section VI of this Standard. In all cases, they shall 

require root shielding with inert gas.

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K. The materials used for pipe purging dams and methods employed in their 

placement, use, and subsequent removal shall be as required to ensure that no 

damage results to the piping or related components. 

L. The method that is proposed by the Vendor to obtain and maintain adequate root 

shielding shall be included either as part of the submitted welding procedure or as 

a separate standard for review. The procedure for root shielding by inert gas shall 

contain the following: 

1. The composition and purity of shielding gas to be used. 

2. Flow rates and time required to obtain adequate purging. 

3. Pipe dam details materials to be used, type of construction, method of 

placement and removal. 

M. Unless otherwise specified, back-purging (root shielding), when required, shall be 

maintained until completion of 2 weld layers. 

N. Weld joint tolerances for root opening and alignment shall meet the requirements 

of applicable codes and POLARIS Engineering Standards, and also the weld joint 

sketches contained in the submitted welding procedures to ensure against lack of 

penetration and lack of fusion. 

O. For shop and field fabrication, when poorly fitted joints occur with excessive joint 

gap or excessive offset, the Vendor shall submit a separate weld repair procedure 

indicating with a sketch the method proposed to bring the joint back to original 

design requirements in conformance as close as possible to the original Client 

accepted welding procedure. The Vendor cannot assume that backing rings or 

strips, permanent or temporary, are acceptable without the Client's review. Any 

weld joints of this nature found to be slugged with supplementary filler metal are 

unacceptable. The weld build up of beveled ends to close excessive gap is 

unacceptable unless a Vendor welding procedure is submitted for doing so and is 

accepted by the Client. 

P. Grinding and cleaning of stainless steels and nonferrous material shall be done 

only with tools that will not leave detrimental deposits on the base metal; 

aluminum oxide or silicone carbide grinding wheels and austenitic stainless steel 

wire brushes shall be used. These tools shall not have been previously used on 

other than the material to be cleaned. 

Q. Surfaces to be welded shall be clean and free of paint, oil, dirt, scale and other 

foreign materials, which may contain lead, sulfur, and other low melting point 

elements detrimental to welding. Beveled edges are to be cleaned and coated with 

deoxaluminate paint prior to shipment. Preparation of the bevel just prior to 

welding shall be as specified on the applicable welding procedure specification.

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R. Penning of welds to enhance mechanical properties is prohibited. 

S. Tack welds which are to be incorporated into the final weld shall be subject to all 

the same requirements as the applicable welding procedure, including preheat, 

and are to be performed by welders qualified to perform the welding procedure 

accepted for that joint. If separate tackers are used other than the welder 

performing the joint weld, they shall be qualified for performance on all the same 

welding variables for the portion of the weld they perform as stated in the 

applicable accepted welding procedure or else the tack welds shall be completely 

removed. 

T. Tack welds shall be made with filler metal of the same composition as will be 

used for the first pass of the weld as stated in the applicable accepted welding 

procedure for the joint. 

U. All slag shall be thoroughly removed from tack welds and the leading and trailing 

edges shall be blend ground to a feather edge prior to welding the root pass or 

covering pass. 

V. Tack welds that violate any of the above requirements shall be completely 

removed. Completed welds having tack welds found to violate any of the above 

shall be subject to complete removal. 

W. Removable start-up and run-off tabs shall be used for longitudinal welds. 

Materials used for these tabs shall be of the same composition as the base weld. 

X. For alloy clad plate and material, the following limitations shall apply for 

preparation at the joint prior to back-cladding: 

1. Cladding shall be stripped back to a minimum of 1/4 inch from the edge of 

base material bevels by machining, grinding or arc gouging. 

2. Removal of the cladding shall not reduce the base material thickness 

below the design thickness. 

3. A minimum radius of 1/16 inches shall be used at the limit of cladding 

removal unless the clad material is beveled at least 30 o . 

4. Preparation of local repair cavities in overlay welds that penetrate into the 

base material more than 10% of its thickness, or 3/16 inch, whichever is 

less, shall have the base material rewelded with the appropriate Client 

accepted welding procedure consistent with the base material prior to 

completing the overlay repair. 

5. Copper sulfate test to ensure complete cladding removal.

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Y. Strip type lining shall be attached to the shell circumferentially and shall be 

designed so that the distance between attachment welds does not exceed that 

shown below. The weld between the strips shall be at least 1/4 inch and not more 

than 1/2 inch in width. Strip lining shall be a multi-pass fillet-butt weld of three 

(3) weld minimum design with 100% dye penetrant testing of final weld. See 

Figure A below. 

Figure A 

Strip Welding Linings 

Vessel Operating Temperature 

Distance Between Welds 

650 ºF and Under 4 inches 

Over 650 o F 

Not permitted (See VII.Z) 

Z. Vessels with integrally clad type linings shall be made of explosion bonded plate 

or plate clad with the required lining material in the steel mill in accordance with 

the mill’s standards. These standards are to be approved by Client. 

AA. 

BB. 

CC. 

Weld overlays shall consist of at least two layers so that the required depth of the 

top layer will have the alloy composition required for the service. The first layer 

may be made with electrodes of higher alloy content to compensate for dilution 

effects. The finished surface shall be 100% examined by the liquid penetrant 

method of examination. 

All stubs, rods, flux, slag or foreign material shall be removed from the equipment 

or piping after completion of welding and prior to postweld heat treatment or 

hydrostatic test. 

The use of temporary welded attachments shall be avoided where possible. All 

locations of removed temporary attachments shall be examined visually after 

removal of the attachment. 

1. Temporary attachments shall be removed by flame cutting, arc gouging or 

grinding. Hammering off is not permitted. (This paragraph does not 

apply to atmospheric storage tanks within the scope of Standard 1115.1 

and API 650.) 

2. Defects discovered in the base metal such as gouges, cracks or undercuts

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shall be removed and repaired and the area re-examined using the same 

method of NDT that revealed the original defect. 

DD. Vertical welding shall be performed vertical up. Downhill welding is not 

permitted except for the GMAW root pass only. 

EE. 

FF. 

For field erection of API storage tanks, the weld seams of sketch plates for tank 

bottoms and floating roofs shall contain a minimum of two weld passes. Single 

pass seams are not acceptable. 

Branch Connections 

1. Branch connections such as weldolets, threadolets, sockolets, and stub-ins 

shall be joined to the header by full penetration welds. Incomplete 

penetration as defined by Table 341.3.2, Note B of ASME B31.3, is not 

acceptable. 

2. Start and stop welds on root pass shall be feathered in. 

3. Branch connections shall be prepared in accordance with Figure 328.4.4 

(A), (B) or (C) of ASME B31.3. A minimum root gap of 1/16 inches shall 

be maintained during welding. The root gap shall be stated in the welding 

procedure specification. 

VIII. 

PREHEAT AND INTERPASS TEMPERATURES 

A. Preheat shall be at least sufficient to dry surfaces to be welded but not less than 

50 o F. Higher temperatures may be required for highly restrained joints such as 

closely spaced nozzles. Carbon steel plates 1.25 inch thick or more, shall be 

preheated to 200 o F minimum and ferritic alloy plates to 300 o F minimum prior to 

flame cutting and ground smooth prior to welding. All such prepared edges 

including holes cut for nozzles or manways, shall be liquid penetrant examined or 

magnetic particle inspected for cracks or laminations. 

B. Minimum preheat temperatures shall not be less than that stated in ASME, 

Section VIII, Division 1, Appendix R and Paragraph UCS 56; ASME B31.1, 

Paragraph 131; or ASME B31.3, Table 330.1.1, as applicable. Minimum preheat 

temperatures are required to be stated on the welding procedure specification. 

C. Preheat maintenance shall be applied when required by the Client for the 

conditions stated below. Preheat maintenance is the maintenance of the stated 

minimum preheat temperature, without interruption, from start to completion of 

welding. Vendor must either state on the WPS or weld map that preheat is to be 

maintained when so required by Section VIII of this Standard. Loss of preheat 

maintenance will require complete liquid penetrant or magnetic particle 

inspection of the uncompleted seam prior to any further welding. Any defects 

found must be reported to the Client's Inspector for his review.

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D. Preheat maintenance is required for the following: 

1. Equipment and piping, regardless of service or wall thickness, of the P-5B, 

C, and D material groups (where chrome content exceeds 4%) and of P-6 

and P-7 materials. 

2. Modifications to existing equipment and piping, regardless of material or 

wall thickness in hydrogen service. Hydrogen service is defined as: Any 

service in which the partial pressure of hydrogen in the fluid handled is 50 

psia or more. This work requires a hydrogen bake-out, pre-heat 

maintenance and PWHT. 

3. Pressure vessel and exchanger seams, nozzle and attachment welds of P-1, 

P-3, P-4 and P-5 group materials, regardless of service, if shell or head 

thickness is equal to or greater than 1-1/2 inch. 

4. Piping fabrication, regardless of material or service, if thickness is equal to 

or greater than 3/4 inch. 

E. The same preheat requirements shall be met as are required on the Client accepted 

welding procedures for thermal cutting, gouging, tack welding and welding 

repairs. 

F. The maximum preheat and interpass temperature for P-8 materials shall be 350 o F. 

The maximum preheat and interpass temperature shall be specified on the WPS 

for all materials of material group P-7 and higher. 

IX. 

POSTWELD HEAT TREATMENT 

A. Postweld heat treatment (PWHT) shall be performed in accordance with the 

ASME Code and/or POLARIS Engineering Standard 840.4, as applicable. The 

applicable code or Standard for PWHT shall be referenced on the weld map 

(Appendix I). The maximum and minimum holding temperature and holding time 

shall also be stated on the WPS. POLARIS requires a two (2) hour minimum 

holding time for all equipment and piping to be heat treated. 

1. For all equipment, except field fabricated tanks and piping, the post weld 

heat treatment procedure outlined in the ASME Code, Section VIII, 

Paragraphs UW-40, UW-49, and UCS-56, shall be followed. The 

exemptions provided for in the notes to Table UCS-56 are permitted with 

Client approval. 

2. Complete temperature cycle of heating, soaking and cooling shall be 

recorded on a chart and a copy of the continuously temperatures shall be 

provided to the Client for record. Cooling rate and heating rate shall be 

recorded on the WPS.

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3. Minimum and maximum PWHT temperatures and minimum holding time 

shall be as specified in the appropriate code and/or POLARIS Engineering 

Standard, except as specifically noted below: 

a. All carbon steel vessels, exchangers, and piping requiring PWHT 

are to be postweld heat treated at 1150 o F maximum (± 25 o F) for a 

minimum of two (2) hours. 

b. All 1-1/4% Cr - 1/2% Mo vessels, exchangers and piping are to be 

postweld heat treated at 1325 o F maximum (± 25 o F) for a 

minimum of two (2) hours. 

c. All 5% Cr - 1/2% Mo and 9% Cr – 1% Mo vessels, exchangers and 

piping are to be postweld heat treated at 1350 o F maximum (± 25 

o F) for a minimum of two (2) hours. 

d. All carbon steel and low chrome piping shall be postweld heat 

treated in accordance with POLARIS Engineering Standard 840.4. 

B. Postweld heat treatment may be required for carbon steel equipment and piping 

for certain service conditions even when not mandatory per the applicable code or 

standard. Postweld heat treatment for these services will be indicated by the 

POLARIS Engineering Standards. 

At a minimum the following items shall be post weld heat treated: 

1. Unless otherwise specified, welds in amine equipment and piping shall be 

postweld heat treated regardless of operating temperature or concentration. 

This also includes piping and equipment, which may be at risk of amine 

contamination as defined by the project P & ID's. 

2. Unless otherwise specified, welds in caustic equipment and piping shall be 

postweld heat treated regardless of the operating temperature or caustic 

concentration. This also includes piping and equipment, which may be at 

risk of caustic contamination as defined by the project P & ID's. 

3. Postweld heat treatment is required for equipment as well as shop and 

field fabricated piping of 1-1/4 Cr and higher ferritic steel weldments 

regardless of thickness. 

4. Postweld heat treatment is required for equipment as well as shop and 

field fabricated piping of carbon steel weldments regardless of thickness 

when design operating conditions are within 200 o F of the Nelson Curve 

for that material. 

5. All carbon steel equipment and piping in sour service with a fluid pressure

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of 65 psia or greater and containing hydrogen sulfide (H 2 S) at a partial 

pressure in excess of 0.05 psia (mol-fraction multiplied by total system 

pressure) with, or without, water present. 

6. All deaerators require post weld heat treatment. 

7. All equipment in these services above shall have welds ground, smooth, 

and wet fluorescent magnetic particle tested. 

C. Postweld heat treatment temperatures will be in accordance with ASME B31.3, 

Table 331.1.1 and POLARIS Engineering Standards 840.1 and 840.4. 

D. Acceptable methods for postweld heat treatment are: 

1. Furnace method 

2. Local resistance method 

3. Local induction method 

Other methods for postweld heat treatment require Client's written approval. 

E. For piping, postweld heat treatment performed by exothermic methods requires 

Client's written approval and shall not be assumed as acceptable by the Vendor 

during bid preparation. When approved by Client, welding procedures submitted 

for review using postweld heat treatment by exothermic methods shall be 

qualified as using the exothermic method proposed for heat treatment. All weld 

joints postweld heat treated by exothermic methods, when approved, require 

100% radiography. 

F. Postweld heat treatment for stainless steels of Material Group P-8, nonferrous 

materials or dissimilar materials requires approval by the Client. 

G. Direct impingement by torch or furnace burner is not acceptable. Threads and 

gasket surfaces shall be protected from excessive oxidation during heat treatment. 

H. Equipment and piping postweld heat treated for any reason, code or process, shall 

not be subjected to any further welding, hammering, pressing or forming after 

postweld heat treatment without Client approval. 

I. Postweld heat treatment procedures describing cleaning requirements, heating and 

cooling rates, thermocouple locations, type of heating, equipment, etc., shall be 

submitted to the Client for review and approval to proceed. 

J. For local postweld heat treatment of thicknesses greater than 2 inches, the Vendor 

shall verify that the minimum code required PWHT temperature is attained on the 

unheated side of the joint. Verification may be established either by the

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attachment of thermocouples or by the submittal of test data. 

K. PWHT is always required for all piping in which the wall thickness is 3/4” or 

greater. 

X. NON-DESTRUCTIVE EXAMINATION, TESTING AND INSPECTION 

A. Non-destructive examination (NDE) shall be performed and results evaluated in 

accordance with the requirements of the applicable ASME code, ANSI standard, 

or API standard. Any additional NDE required above and beyond the above 

mentioned codes and standards shall be as specified in this Standard and other 

POLARIS Engineering Standards. 

B. As a minimum, or when non-destructive examination is not specified, all welds 

shall be visually examined. 

C. Plate 2 inches and thicker and clad material shall be 100% ultrasonically tested at 

the mill with acceptance to SA-578, Level B. 

D. Brinell Hardness Tests 

1. Hardness tests shall be performed when PWHT is specified, and when 

required by codes, standards or POLARIS Engineering Standards. 

Hardness test results shall be given in equivalent Brinell values regardless 

of test method utilized. A test shall include one (1) examination in the 

weld and one (1) in each heat affected zone at the toe of the weld. 

2. Hardness tests on piping shall be taken as specified in POLARIS 

Engineering Standards 840.1 and 840.4. 

3. Hardness tests on pressure vessels, exchangers, and other equipment 

where required shall be taken as follows: 

a. One test for one longitudinal seam per course section, on the inside 

surface where practical. 

b. One test for each circumferential seam per 50 linear feet of weld, 

on the inside surface where practicable. 

c. One test for each major joint weld for box-type headers on air 

coolers. 

d. One test for each size nozzle 4 inches and over in size, if 

accessible.

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e. As a minimum, one test shall be taken for each welding process 

employed on pressure containing welds and also one test per 

welder or welding machine operator. 

f. As required in the applicable code or standard. 

4. When PWHT is required, hardness tests shall be performed after PWHT. 

5. Where NACE MR-0175 and/or RP-0472 are specified the hardness testing 

requirements of those standards shall apply where more stringent than this 

Standard. 

6. Results of hardness tests shall be documented by the Vendor for review by 

the Client's Inspector. The Client's Inspector shall be consulted on choice 

of location for tests. 

7. Hardness tests exceeding the maximum Brinell Hardness Number (BHN) 

allowed shall have two more tests taken near each failed location and both 

are required to be within the maximum acceptable hardness requirements. 

8. Hardness test results shall be reported with the procedure qualification 

record by the Vendor with submittal of welding procedure review by the 

Client for the following: 

a. Whenever hardness tests are required by codes or standards. 

b. Whenever equipment or piping is to be postweld heat treated. 

c. Whenever automatic or machine type welding processes are 

employed, or whenever FCAW is to be utilized. 

d. Hardness for carbon steel shall not exceed 200 BHN; hardness for 

low alloy shall be in accordance with applicable codes or 

standards. For other materials requiring hardness testing, 

acceptance values shall be as stated in the applicable codes and 

standards. 

E. Production test requirements on weld overlay and back-cladding on vessels and 

exchangers are as follows: 

1. One chemical analysis of overlay from each girth section and component 

(such as head, tubesheet, etc.) and from each back-cladded longitudinal 

and circumferential seam. Also, back-cladded manway attachment and a 

representative number of nozzles, at least one of each size. Production 

tests shall include a minimum of one test per welding process utilized and 

one test per welder or welding operator employed.

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2. For austenitic stainless steel, the overlay or back-clad for TP 347 stainless, 

when specified, shall have elements Cr, Ni, Mn, Si, C and Cb reported. 

3. For others, the overlay or back-clad shall meet the minimum requirements 

of the specified alloy. 

4. Ferrite content of austenitic stainless steel overlay and back-cladding shall 

be checked by using a magnetic gage or other method approved by the 

Client. Range of ferrite shall be 3-12 FN per magnetic meter. 

F. Weld overlays and back-cladding for vessels and towers shall be examined by a 

standard copper sulfate test prior to hydrostatic test and by liquid penetrant 

examination following hydrostatic test. Overlay clad tubesheets shall be liquid 

penetrant examined prior to hydro static test. 

G. The Client's Inspector shall be authorized to reject work or materials and require 

repair or corrections where the applicable specifications or acceptance levels have 

not been met. 

H. The Client's Inspector may require additional examination over and above the 

minimum specified. If the weld proves to be acceptable, the cost of examination 

shall be borne by the Client. If the weld proves to be unacceptable, the cost of the 

examination, and all required repairs and re-examination shall be borne by the 

Vendor. 

I. Root and final welds in vessels, air cooler box headers, exchangers and piping 

larger than 24 inches shall be magnetic particle examined when the material 

thickness is equal to or greater than the following: 

MATERIAL GROUP 

THICKNESS (INCH) 

P-1 1-1/4 

P-3 3/4 

P-4 5/8 

P-5 All 

P-6 All 

P-7 All 

J. Welds in all non-magnetic materials, either of solid alloy or alloy clad plate shall 

be examined by liquid penetrant methods. 

K. Where strength welds for tube to tubesheet joints are required, Vendor shall 

submit a cut-off sample before fabrication.

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L. Pressure retaining butt welds in shell or heads over 1.80 inches thick may be 

manual arc process welded and shall be radiographed 100%. 

M. Heads fabricated from more than one piece shall have welds radiographed 100% 

prior to forming. 

N. For equipment and piping requiring PWHT all required NDE of completed welds 

shall be performed after the postweld heat treatment. 

XI. 

REPAIRS 

A. Welding repairs shall be performed utilizing Client approved welding procedures 

under conditions and requirements as stringent as those imposed by the welding 

procedure originally accepted for the particular weld. 

B. The repair procedures, using welding, shall be submitted for review and shall 

include the following: 

1. The method of defining the type and the extent of the defect. 

2. Methods used for removing the defect, and testing conducted to ensure 

that the defect has been removed. 

3. Welding procedures employed for re-welding and NDE methods used to 

inspect weld repair area after completion of the welding. 

C. Unacceptable discontinuities shall be completely removed by chipping, gouging, 

grinding or other Client authorized methods (for the type of material being 

repaired) to clean to sound metal and the excavated area shall be examined by 

magnetic particle or liquid penetrant methods to assure complete removal of 

defects. 

D. Excavation for repairs by flame or arc gouging shall have the same preheat 

requirements imposed as the welding procedures used to perform the weld. 

E. Preheat to be used for repair welding (such as attachments, undercutting, and 

other defects which do not penetrate the full weld thickness) shall be the same as 

required for the original weld for the full base metal thickness. 

F. Undercutting shall be repaired by blend grinding provided the required base metal 

thickness by design is not reduced. Otherwise, weld metal buildup will be 

required. 

G. Defective work or materials that have been weld repaired shall, as a minimum, be 

re-examined by the same non-destructive test method by which the defect was 

originally located.

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H. Only two repair attempts shall be allowed on any one defective area. No further 

attempts to repair shall be carried out without authorization of the Client. 

XII. 

SUMMARY OF WELDING VARIABLE LIMITATIONS, RESTRICTIONS, 

AND OTHER REQUIREMENTS 

Limitations, restrictions and other requirements of this Standard, whether required by 

ASME Section IX or not, are required to be stated in the Vendor's WPS, PQR and weld 

map (Appendix I), on welding procedures submitted by the Vendor for review. The main 

requirements are summarized as follows: 

A. Impact test results on PQR. 

B. Brinell hardness test results on PQR. 

C. Mode of transfer for GMAW and FCAW to be stated on WPS and weld map of 

Appendix I. 

D. GMAW: Limitations and requirements. 

E. FCAW: Limitations and requirements. 

F. Automatic or machine type SAW to be specified in WPS. 

G. Filler metals and fluxes. To have stated in the WPS and/or weld map (Appendix 

I) the AWS grades ASME specifications, Manufacturers, and trade names of filler 

metals and fluxes. 

H. When backing is approved for use, it is required to be stated on PQR, WPS and 

weld map (Appendix I). 

I. Root shielding (back purge) method to be stated on WPS or separate procedure 

submitted. 

J. Minimum preheat temperature to be stated in WPS. 

K. Preheat maintenance when required to be stated in WPS. 

L. Maximum preheat and interpass temperature to be stated on WPS for P-7 group 

materials and higher. 

M. Postweld heat treatment holding temperature and holding time to be specified on 

weld map (Appendix I) and in WPS. 

N. Additional welding variables to be stated in the WPS whether essential or nonessential 

per ASME Section IX are:

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1. Electrical characteristics: current and voltage ranges, and polarity, for all 

welding processes. 

2. AWS specification for non-consumable electrode for GTAW. 

3. Travel speed and whether single or multiple arc for automatic processes of 

GTAW, GMAW, SAW, FCAW/CO2 and for overlay and back-clad 

welding. 

4. Amount of bead overlap, extent of oscillation and wire size for overlay 

and back-clad welding. 

O. Block welding is prohibited. However, The Temper Bead Welding Technique per 

NBIC is allowable with Client’s written approval. 

P. When welding titanium, each bead and adjacent base metal shall be cleaned to 

remove all surface discoloration prior to deposition of the next bead. The final 

weld surface may have intermittent, iridescent straw-colored oxides. 

Q. The root pass of butt welds in lube oil piping, accessible from one side only, shall 

be welded with the GTAW process. 

XIII. 

PROCEDURE FOR REVIEW AND ACCEPTANCE OF VENDOR WELDING 

PROCEDURES 

A. The Client requires Vendors and their Subvendors, if applicable, to submit a copy 

of each welding procedure appropriate for fabrication. A copy of the weld map 

(Appendix I) shall also be filled out and attached to the submittal. Procedures 

cannot be reviewed unless accompanied by the weld map. 

B. Submittals of welding procedures for review shall be directly to the Client and/or 

Client's Engineer. No portion of this Standard shall be waived without written 

approval. 

C. Vendors shall review the welding procedures of their own Subvendors for 

compliance to this Standard prior to submitting for review and acceptance. 

D. The Client and/or Client's Engineer will review the submitted welding procedures 

and weld map and make comments back to the Vendor in writing. Comments are 

either (1) Acceptable without comment, (2) Acceptable with comments, (3) 

Revise and resubmit per comments or (4) Unacceptable with comments. All 

comments, if possible, will make reference the paragraph number of this Standard 

with which the procedure must comply.

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E. Upon receiving the marked up welding procedure from the Client and/or Client's 

Engineer, the Vendor must comply with the comments. The Vendor shall submit 

corrected documents. The Surveillance Inspector assigned by the Client is to 

verify that welding will be performed to the accepted and corrected welding 

procedures, which incorporate the comments. Items in dispute shall be resolved 

prior to fabrication being stated on the affected parts.

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Supplier Name 

Supplier Shop Order # 

POLARIS PO # 

Item/Tag # 

APPENDIX I 

WELD MAP 

Pressure Vessel 

Heat Exchanger 

Storage Tank 

Design Temperature 

Fabricated Pipe Spools 

Design Pressure 

Other 

Min. Design Metal Temp. 

Postweld Heat Treatment Yes No Required by Code Service 

Time and Temperature 

Impact Testing Yes No Required by Code Service 

Temperature 

Applicable Code or Standard 

Draw a single-line sketch of the apparatus. For pipe spools, only show typical weld joints, i.e., butt, branch, and attachments, by 

P-No. 

Locate an example of all types of typical weld joints, dissimilar welds & attachments 

Identify each different welding procedure by separate letter or number. 

This form completed by 

This space for POLARIS Review Stamp 

Email Address 

Telephone 

Revision 

Date 

This space for POLARIS Identification

General welding, fabrication and inspection table of contents page

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