General Requirements for Welding of Piping

Welding of piping General requirements

LINDE STANDARD

LS 145-10 Part 01

Page 1 of 7

Remarks on the current issue:

Revision: general revision Previous issues: 08.95, 08.98, 10.00, 05.01, 11.04, 05.07, 07.10 Responsible department(s) for the technical content: GCQ Confidentiality class 2 in accordance with LS 104-03: For project specific use only

X 07 08.2012 GCQ / Henn GCQ / Helmreich LEHQ-ENM1S / Alekseev X 06 07.2010 GC-QM / Henn GC-QM / Helmreich TAW-N / Alekseeva X 05 05.2007 TM-Q / Henn TM / Walser TAW-N / Schmitt

Status Issue Date Prepared Checked Approved Refer to protection notice ISO 16016. File name: LS 145-10.T01 (EN)

Contents

1 Scope ................................................................ 22 References ........................................................ 22.1 Normative references ........................................ 22.2 Informative references ...................................... 23 Abbreviations and definitions ............................ 24 Requirements for the CONTRACTOR .............. 34.1 Health and safety .............................................. 34.2 Quality management system ............................. 34.3 Subcontracting of work ...................................... 34.4 Welding specifications ....................................... 34.5 Welding qualifications ....................................... 34.6 Welding consumables ....................................... 55 Performance of work ......................................... 55.1 General requirements ....................................... 55.2 Welding supervision .......................................... 65.3 Weld marking .................................................... 65.4 Postweld heat treatment ................................... 66 Testing / examination ........................................ 67 Documentation .................................................. 6Annex A (normative) Forms .................................. 7Annex B (normative) Normative documents for

application in the People's Republic of China ....................................................... 7

Linde AG, Engineering Division Issue 07/08.2012 LS 145-10 Part 01 Page 2 of 7

Refer to protection notice ISO 16016. File name: LS 145-10.T01 (EN)

1 Scope This Linde Standard (LS) contains general minimum requirements for the welding of piping made of metallic materials for fabrication in workshops and on site including prefabrication. It shall apply to fabrication of new as well as to repair and modification of existing pipe systems and piping. These minimum requirements do neither release the CONTRACTOR from the adherence to the general acknowledged rules of technology nor from the observance of over ranking standards and codes requirements.

Project-specific requirements have priority over this LS. Deviation from this LS shall be approved by COMPANY in writing in advance.

2 References 2.1 Normative references This LS contains provisions which, through dated or undated references in this text, constitute provisions of other publications. The normative references are cited at the respective place in the text and the publications are listed below. For dated references, subsequent amendments to, or revisions of, any of these publications do not apply. For undated references, the issues valid at the effective date of contract shall apply. ISO 3834-2 Quality requirements for fusion welding of metallic materials - Part 2: Comprehensive quality requirements ISO 9001 Quality management systems - Requirements ISO 9606-2 Qualification test of welders - Fusion welding - Part 2: Aluminium and aluminium alloys ISO 9606-4 Approval testing of welders - Fusion welding - Part 4: Nickel and nickel alloys EN 287-1 Qualification test of welders - Fusion welding - Part 1: Steels ASME IX ASME Boiler & Pressure Vessel Code - Section IX: Welding and brazing qualifications GB/T 12467.2-2009 Quality requirements for fusion welding of metallic materials - Part 2: Comprehensive quality requirements LS 145-10 Part 02 Welding of piping Welding consumables

2.2 Informative references ISO 4063 Welding and allied processes - Nomenclature of processes and reference numbers EN 10204 Metallic products - Types of inspection documents

3 Abbreviations and definitions COMPANY LINDE AG, Engineering Division CONTRACTOR The party which is awarded a contract from COMPANY SUB-CONTRACTOR The party which is awarded a contract from CONTRACTOR SMAW Manual metal arc welding (metal arc welding with covered electrode);

shielded metal arc welding. Reference number 111 according to

ISO 4063 GTAW Gas Tungsten Arc Welding using inert gas and solid filler material

(wire/rod). Reference number 141 FCAW Gas Metal Arc welding using active gas and flux cored electrode.

Reference number 138 DN Designation followed by a dimensionless number for the nominal diameter acc. to DIN/EN NDE Non Destructive Examination NPS Designation followed by a dimensionless number for the nominal diameter acc. to ASME PQR Procedure Qualification Record PTFE Polytetrafluorethylene WPS Welding Procedure Specification



4 Requirements for the CONTRACTOR 4.1 Health and safety National health and safety regulations / standards with regard to welding shall be observed.

4.2 Quality management system The CONTRACTOR shall dispose of an adequate quality management system, e.g. according to - ISO 9001 or - shall fulfill the requirements of ISO 3834-21 as a minimum.

COMPANY reserves the right to review the implementation of the quality management requirements.

4.3 Subcontracting of work Subcontracting of welding work, heat treatment and examination of welds by the CONTRACTOR needs the approval in writing by COMPANY. The adherence to all requirements stipulated by contract including the observance of this LS remains the responsibility of the CONTRACTOR. COMPANY reserves the right to audit SUB-CONTRACTORs.

4.4 Welding specifications For welds on pressure bearing piping, incl. repair welding and tack welding, qualified welding processes acc. to the specified code with relevant WPS shall be used. These documents prepared by the CONTRACTOR incl. a summary list (WPS-List) shall be submitted to COMPANY for review prior to start of fabrication. WPS documents and the WPS-List shall contain an allocation of applicable pipe classes to the WPS.

4.5 Welding qualifications Applicable regulations and standards for qualification of welding processes, welding supervisors and welding personnel / operators shall be taken from the project specifications.

Prior to start welding on sites or on prefabrication places each welder shall pass a welder performance test for the materials to be welded and for the welding processes to be used. The CONTRACTOR bears the costs. The test shall take place in presence of COMPANY; the CONTRACTOR is responsible for provision of test pieces and welding consumables as well as for testing and evaluation of the test pieces (test piece dimensions and welding positions see Figure 1 and 2).

As a part of the welder site approval, the first 3 pipe welds of each welder shall be radiographed resp. ultrasonic tested in addition to the specified scope of non-destructive testing. The CONTRACTOR bears the costs.

The conditions for welder performance test specified in Table 1 shall apply to welders who have already been qualified for welding according to project related code requirements. The test pieces shall be welded according to valid WPS.

The record 'Welder performance test' according to LS 145-10 Part 01, Form 01 shall be used for the documentation of the welder performance test.

1 For application in the People's Republic of China see Annex B



90

a) Pipe axis horizontal b) Pipe axis vertical a) Pipe axis horizontal b) Pipe axis vertical

Figure 1: Test piece DN 150 / NPS 6

Figure 2: Test piece < DN 150 / NPS 6

Table 1: Welder performance test Materials to be welded

Conditions and tests

Unalloyed and low-alloy steel

( 2,5% Cr, 1%Mo) Ni-steel

(3,5% bis 9% Ni) CrNi-steel

(austenitic and duplex)

Cr-steel (> 2,5% Cr)

Aluminum

Welding process 1), 6)

SMAW, GTAW,

GTAW/SMAW, FCAW

SMAW GTAW

GTAW/SMAW

SMAW GTAW

GTAW/SMAW

GTAW GTAW/SMAW

GTAW 2)

Material of test piece Carbon steel 3)

Test piece dimensions

SMAW, GTAW/SMAW and FCAW: DN 150 / NPS 6 (1 test piece acc. Fig. 1), length 350mm

4)

GTAW: < DN 150 / NPS 6 (2 test pieces acc. Fig. 2), length 350mm

Welding positions

SMAW, GTAW/SMAW and FCAW:

- Pipe axis horizontal, welding positions: flat, vertical-up, overhead acc. to Figure 1a.

- Pipe axis vertical, welding pos. horizontal acc. to Figure 1b. GTAW: - Test piece 1: pipe axis horizontal, welding positions: flat, vertical-up,

overhead acc. to Figure 2a. - Test piece 2: pipe axis vertical, welding pos.: horizontal acc. to Figure 2b.

Distance of the test piece to the floor max. 600 mm

Evaluation 5) - Visual: excessive root and cap penetration < 2mm, no negative root, single undercuts < 0.5mm - Radiography: acc. to applicable Code Report LS 145-10 Part 01, Form 01 shall be used and filed by CONTRACTOR. 1) At acceptance of the combined process GTAW/SMAW a separate GTAW-testing is not required. 2) - GTAW with CrNi/Al-backing ring or

- GTAW both-sides simultaneously welding or - GTAW one-side welding

Tests shall be performed for welding processes concerned. 3) The most critical material of each group shall be used. 4) GTAW with backing ring: DN 150 / NPS 6 (1 test piece):

- Pipe axis horizontal, welding positions: flat, vertical-up, overhead acc. to Figure 1a. - Pipe axis vertical, welding position horizontal acc. to Figure 1b.

GTAW both-sides simultaneously: DN 300 / NPS 12 (1 test piece) acc. to Figure 1a: - Pipe axis horizontal, pipe rotating, welding position vertical-up.

GTAW one-side welding: < DN 150 / NPS 6 (1 test piece) acc. to Figure 2a: - Pipe axis horizontal, pipe rotating, welding position flat.

5) No grinding of root or top layer accepted after completion of weld. 6) The use of other welding processes requires approval by COMPANY.



4.6 Welding consumables The welding consumables shall be suitable for the welding processes and the materials to be joined. CONTRACTOR shall provide an inspection document, e.g. 'Test report 2.2' according to EN 10204. The mechanical properties and the resistance against corrosion of the weld deposit shall meet the requirements of the base metal. The temperature limits of the welding consumables shall correspond with the design temperatures of the piping. Manufacturer's recommendations shall be observed as far as storage and handling of the welding consumables are concerned.

For welding consumables recommended by COMPANY see LS 145-10 Part 02.

5 Performance of work 5.1 General requirements a) Prior to start of welding work the CONTRACTOR shall take care for appropriate protection against

atmospheric influences. b) During welding of the root and 2nd layer the pipe ends shall be closed. c) Pressure bearing butt welds and socket welds shall be min. 2-layer welds with weld-stops and-starts

staggered. Butt welds shall be performed as full penetration welds. d) For metal temperatures < 5 C or at danger of condensate formation the weld zone shall be preheated to

at least 80 C. e) During welding the earthing shall be fixed on the welded part besides the weld. f) The alignment of piping or flange connections by means of welding or other heat input shall be defined in

a written procedure which requires prior COMPANY approval. g) The inner diameters of circumferential welds shall be aligned by mechanical work, if required. A slope of

min. 1:3 shall be kept. h) A non-slagging welding process shall be used for the root pass on single sided welds of process lines. For

field assembly welds only the GTAW process will be accepted for root welding. i) Semiautomatic and automatic welding processes shall not be used for site welding. For pre-fabrication

workshops these processes may be accepted under the provision, that skill and experience can be proven and US-testing shall be performed in addition to radiography in the specified extent.

j) The welds on orifice flanges shall be ground flush on the inside. This shall be documented by CONTRACTOR on the isometric drawings and verified by COMPANY.

k) Temporary or permanent attachment welds on pressure retaining piping parts are subject to the same requirements as for piping welds. The length of such welds shall be min. 20 mm.

l) The material of welded attachments to piping parts shall be identifiable. m) In order to minimize the distortion of flange sealing surfaces, flanges DN 700 / NPS 28 should be

counter-flanged during welding. n) Seal welding of threaded joints shall be carried out in such a way, that sealing agents (PTFE, sealing

paste etc.) are completely removed prior to welding. Threads shall be covered by the weld seam. o) Interpass temperature for austenitic materials shall be 170C. p) Austenitic pipes shall be purged with purging gas during the entire welding process. In case the specified

annealing colour (straw yellow) at the top layer or root zone can not be obtained, the CONTRACTOR shall pickle relevant welds and heat affected zones at his own expense. Pickling agents containing chloride shall not be used.

q) For the use of purging paper a written approval by COMPANY is required. r) Valves shall be welded in the open position only. s) After pressure testing welding work is not admissible on pressure-retaining parts of the piping system. t) Longitudinal and circumferential welds which will be covered by welded attachments shall be subject to

radiographic or ultrasonic testing across the covered area prior to welding the attachment. u) Crossing welds shall be avoided. If they can not be avoided, they shall be subject to radiographic or

ultrasonic testing. v) Distance of butt welds: 6 x pipe wall thickness, however minimum 50 mm. w) Prior to assembly, the inside of the piping shall be thoroughly cleaned. x) Welding on piping exposed to external forces is not permitted. y) Welding machines, heat treatment devices and electrode furnaces shall be checked regularly by experts

on their adjustment range. The devices shall be marked by a label with the due date of the next examination.



5.2 Welding supervision The CONTRACTOR is responsible for welding supervision performed by qualified personnel. An actual welders list incl. welder start and stop dates with welder's qualification records shall be handed to COMPANY. The welding repair rate per welder (number of welds volumetrically examined to welds repaired) shall be determined and documented continuously by the CONTRACTOR. The applicable repair rates per material group shall be reported to COMPANY on a weekly basis each for the reporting period and in total.

5.3 Weld marking Each weld shall be marked with the welder mark and weld number directly beside the weld. For steel piping ( 5 mm wall thickness) the marking shall be hard-stamped using low stress stamps. Welds with wall thicknesses < 5 mm as well as all non-ferrite materials (e.g. austenitic CrNi-steel, aluminium, CuNi-materials) shall be marked by engraving. The weld marking shall be transferred to the welding documentation (see Para. 7) and shall be maintained on the component until mechanical completion of the plant.

5.4 Postweld heat treatment Postweld heat treatment such as stress-relieving shall be performed if required by Code or if required in addition to Code, e.g. for fluid-specific requirements. The heat treatment parameters such as annealing temperature, holding time, heating and cooling rates shall be taken from codes and/or material standards and shall be qualified by welding procedure qualifications (PQRs).

The total annealing time (e.g. if further heat treatment cycle required after weld repair) shall be qualified by the welding procedure qualifications (PQRs)

Unless specified otherwise, for unalloyed and low-alloy steels the hardness of the weld deposit and heat affected zone shall not exceed the hardness of the base material +100.

For stress relieving of annealed base materials the temperature shall be minimum 30C below the annealing temperature of the base material.

6 Testing / examination Testing of welds shall be performed acc. project specifications by qualified personnel. The extent of the NDE as well as test pressure shall be taken from the piping lists and/or piping documents. Pressure test medium shall be agreed with COMPANY.

NDE shall always be performed in the course of fabrication covering all welders involved and proportionally pre- and field-fabrication welds.

At detection of a defect the requirements of applicable code shall apply. If the code does not stipulate requirements, the following shall apply:

- DN 300 / NPS 12: Two further welds (tracer welds) welded by the same welder and welding process, shall be examined for each weld to be repaired. If a defect is found again, two further welds per unacceptable tracer weld shall be examined.

- > DN 300 / NPS 12: Two further welds (tracer welds) welded by the same welder and welding process, shall be examined per defect found, in a critical area of min. 20% of the weld length. If a defect is found again, two further welds per defect found shall be examined in a critical area of min. 20% of the weld length.

- If a defect is found in the 2nd tracer weld selection, all welds of the welder and welding process involved shall be examined.

Unacceptable welders shall be stopped immediately. COMPANY shall be informed in writing. Additionally examined welds due to weld repairs shall be excluded from the specified testing scope and to the CONTRACTORs account.

7 Documentation Directly after completion, the welds, the performed heat treatments and NDE shall be documented with a clear correlation to each other. Extent and setup of the documentation to be supplied to COMPANY shall be taken from the project specifications.



Annex A (normative)

Forms

Forms Title Issue

Form 01 Welding of piping Welder performance test Record 02 / 08.2012

For editing the Form click on the title.

Annex B (normative)

Normative documents for application in the

People's Republic of China

Code / Standard referenced in the LS Code / Standard may be applied in the People's Republic of China ISO 3834-2 Quality requirements for fusion welding

of metallic materials - Part 2: Comprehensive quality requirements

GB/T 12467.2*) Quality requirements for fusion welding of metallic materials - Part 2: Comprehensive quality requirements

*) GB/T 12467.2-2009 are identical with ISO 3834-2:2005

Welding of piping

Welder performance test Record

LINDE STANDARD

LS 145-10 Part 01 Form 01

Issue 02 / 08.2012 Page 1 of 1

Linde AG File name: LS 145-10.T01-F01 (EN)

Project No: Project Code: Record-No:

CONTRACTOR: This Welder Performance Test shall prove the capability of the welder to perform acceptable weld seams under typical welding conditions at construction/pre-fabrication site. The test shall be performed acc. to approved WPS prior to start of production welding. This test shall not replace the welder qualification according to applicable Construction Code.

Welder: Name, Surname:

Stamp No.:

Qualified acc. to EN 287-1 ISO 9606-2 ISO 9606-4 ASME IX

Performance test piece:

Welding process

WPS Nr.

Base metal Dimensions

Welding position Preheating temp. C

Welding consumable: Standard designation

Trade name

Manufacturer

Shielding gas Backing gas

Other details CrNi backing ring CrNi+Al backing ring

Evaluation: Joint preparation: Joint geometry, edge misalignment, gap, root face passed

failed

Visual: Excessive root and cap penetration < 2 mm, no negative root, single undercuts < 0.5 mm

passed

failed

Radiographic test: X-Ray Gamma Ray

passed

failed

Result:

Requirements met failed Welders test certificates acc. Code have been verified

CONTRACTOR

COMPANY Signature / Date Signature / Date

Remarks:

General Requirements for Welding of Piping

Documents

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