UNI-EN 12732 (2005)

Trasporto e distribuzione di gas NORMA EUROPEA

Saldatura delle tubazioni di acciaio Requisiti funzionali

UNI EN 12732

FEBBRAIO 2005 Gas supply systems

Welding steel pipework Functional requirements La norma contiene i requisiti per la produzione e il controllo di giunti saldati per l’installazione e la modifica di tubazioni e canalizzazioni d’acciaio terrestri utilizzate nei sistemi per il trasporto e la distribuzione di gas, ivi comprese le tubazioni in servizio per tutte le gamme di pressione per il trasporto di gas naturale trattato, non tossico e non corrosivo in conformità alla ISO 13686 quando: - gli elementi delle tubazioni sono realizzati in acciaio al carbonio non legato o leggermente legato; - la tubazione non è situata in aree commerciali o industriali industri ali come parte integrante del processo industriale su tali aree, ad eccezione delle tubazioni e canalizzazioni utilizzate per il rifornimento di queste ultime; - la tubazione non è ubicata in impianti per uso domestico secondo la UNI EN 1775; - la temperatura di progetto del sistema è compresa tra -40 °C e 120 °C.

TESTO INGLESE

La presente norma è la versione ufficiale in lingua inglese della norma europea EN 12732 (edizione aprile 2000).

ICS UNI Ente Nazionale Italiano di Unificazione

Via Battistotti Sassi, 11B 20133 Milano, Italia

25.160.40

 © UNI Riproduzione vietata. Tutti Tutti i diritti sono riservati. Nessuna parte del presente documento può essere riprodotta o diffusa con un mezzo qualsiasi, fotocopie, microfilm o altro, senza il consenso scritto dell’UNI. www.uni.com UNI EN 12732:2005

Pagina I

PREMESSA NAZIONALE La presente norma costituisce il recepimento, in lingua inglese, della norma europea EN 12732 (edizione aprile apr ile 2000), che assume così lo status di norma nazionale italiana.

La presente norma è stata elaborata sotto la competenza dell’ente federato all’UNI CIG - Comitato Italiano Gas

La presente norma è stata ratificata dal Presidente dell’UNI, con delibera del 18 gennaio 2005.

Le norme UNI sono elaborate cercando di tenere conto dei punti di vista di tutte le parti interessate e di conciliare ogni aspetto conflittuale, per rappresentare il reale stato dell’arte della materia ed il necessario grado di consenso. Chiunque ritenesse, a seguito dell’applicazione di questa norma, di poter fornire suggerimenti per un suo miglioramento o per un suo adeguamento ad uno stato dell’arte in evoluzione è pregato di inviare i propri contributi all’UNI, Ente Nazionale Italiano di Unificazione, che li terrà in considerazione per l’eventuale revisione della norma stessa. Le norme UNI sono revisionate, quando necessario, con la pubblicazione di nuove edizioni o di aggiornamenti. È importante pertanto che gli utilizzatori delle stesse si accertino di essere in possesso dell’ultima edizione e degli eventuali aggiornamenti. Si invitano inoltre gli utilizzatori a verificare l’esistenza di norme UNI corrispondenti alle norme EN o ISO ove citate nei riferimenti normativi. UNI EN 12732:2005

 © UNI

Pagina II

EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM

EN 12732 April 2000

ICS 25.160.40

English version

Gas supply systems - Welding steel pipework - Functional requirements Systèmes d'alimentation en gaz - Soudage des tuyauteries en acier - Prescriptions fonctionnelles

Gasversorgungssysteme - Schweißen von Rohrleitungen aus Stahl - Funktionale Anforderungen

This European Standard was approved by CEN on 16 August 1999. CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the Central Secretariat or to any CEN member. This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom.

EUROPEAN COMMITTEE FOR STANDARDIZATION COMITÉ EUROPÉEN DE NORMALISATION EUROPÄISCHES KOMITEE FÜR NORMUNG

Central Secretariat: rue de Stassart, 36

 © 2000 CEN

All rights of exploitation in any form and by any means reserved worldwide for CEN national Members.

B-1050 Brussels

Ref. No. EN 12732:2000 E

Page 2 EN 12732:2000 Contents

Page

Foreword . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 1

Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

2

Normative references . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

3

Definitions an and a ab bbreviations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

4

Quality system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

4.1 4.2 4.3 4.4

Welding contractors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Welders . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Welding supervisory/co-ordination personnel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Testing personnel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5

Welding co consumables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

6

Production welding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

6.1 6.2 6.3 6.4 6.5 6.6 6.7

General requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Joint preparation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Preheating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Tacking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Welding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Actions af after we w elding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Repair of weld defects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

7

Special pr p rocedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

7.1 7.2 7.3

Attachment of structural parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 Attachment of cathodic protection connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 Hot tapping and other welding work on pressurized pipelines and systems . . . . . . . . . . . . . . 14

8

Inspection of the weld joint . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

8.1 8.2 8.3 8.4 8.5 8.6

General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Scope of inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Non-destructive ex examination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Time of inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Acceptance criteria . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Recording of test results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

9

Documentation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

9.1 9.2

General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 Archiving requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

10

Spec Specif ific ic requ requir irem emen ents ts for for gas gas supp supply ly sy syst stem ems s up to and and incl includ udin ing g 16 bar MOP (distribution) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

10.1 10.2 10.3 10.4 10.5 10.6

General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Welders . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Welding supervisory personnel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Production welding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Acceptance re r equirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Requirements for records and documentation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

10 10 10 10

11 12 13 13 13 13 13

15 15 16 18 18 18

18 19 19 19 20 20

Page 3 EN 12732:2000 11

Specific requirements for gas supply systems greater than 16 16 ba bar MO MOP (t (transmission) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

11.1 11.2 11.3 11.4

General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Welders . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Welding supervisory personnel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Qualification of of we welding pr procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

20 20 20 20

11.5 11.6 11.7 11.8

Production welding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Destructive testing of production welds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Acceptance re r equirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Requirements for records and documentation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

22 23 23 24

12

Specific re requirements fo for me metering, re regulating an and co compressor st stations . . . . . . . . . . . . 25

12.1 12.2

General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 Specific requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

Annex A (informative) Qualification for pipeline welders . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 Annex B (informative) Te T esting of the base material . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 Annex C (informative) Wall tth hickness co compensation/Design ex examples . . . . . . . . . . . . . . . . . . . . . . 30 Annex D (informative) Critical aspects for hot-tap welding or welding welding on gas-pressurized pipelines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 Annex E (informative) Vi Visual iin nspection of of jo joints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 Annex F (informative) Manual ultrasonic testing of weld joints for wall thicknesses between approximately 6 mm and 10 mm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 Annex Annex G (infor (informat mative ive)) Accept Acceptanc ance e criteri criteria a recomme recommenda ndatio tions ns for on-s on-site ite produ producti ction on welds welds . . . . . . 38 Annex H (informative) Recommendations for brazing brazing and aluminothermic welding of anodic bonding leads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47 Annex I (informative) Bibliography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

Page 4 EN 12732:2000 Foreword

This European Standard has been prepared by Technical Committee CEN/TC 234 "Gas supply", the secretariat of which is held by DIN. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by October 2000, and conflicting national standards shall be withdrawn at the latest by October 2000. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and t he United Kingdom. There is a complete suite of functional standards prepared by CEN/TC 234 „Gas supply“ to cover all parts of the gas supply system from the input of gas to the transmission system up to the inlet connection of the gas appliances, whether for domestic, commercial or industrial purposes. In preparing this standard a basic understanding of gas supply by the user has been assumed. Gas supply systems are complex and the importance on safety of their construction and use has led to the development of very detailed codes of practice and operating manuals in the member countries. These detailed statements embrace recognised standards of gas engineering and the specific requirements imposed by the legal structures of the member countries. CEN/TC 234 will continue its work updating this Standard to the latest developments at regular intervals. This European Standard has been prepared under mandate M/017 given to CEN by the Commission of the European Communities and the European Free Trade Association. 1

Scope

This European Standard contains requirements for the production and testing of weld joints for the installation and modification of onshore steel pipelines and pipework used in gas supply systems, including in-service pipelines, for all pressure ranges for the carriage of processed, non-toxic and non-corrosive natural gas according to ISO 13686, where -

the pipe pipeline line element elementss are made made of unall unalloye oyedd or low-a low-alloy lloyed ed carbo carbonn steel; steel;

-

the pipeline pipeline is is not locat located ed within within comm commerci ercial al or indus industria triall premise premisess as integr integral al part part of the industrial process on those premises except for any pipelines and facilities supplying such premises;

-

the pipew pipework ork is not not located located withi withinn househo household ld instal installati lations ons accor accordin dingg to EN 1775:1 1775:1998 998;;

-

the desig designn temper temperatu ature re of the syst system em is betw between een -40 -40 °C and 120 120 °C inclusi inclusive. ve.

With respect to production and testing of welds, this European Standard refers to basic standards drafted by CEN/TC 121 and CEN/TC 138 as they exist up to the date of issue of this standard. This standard is not applicable to welds produced prior to the publication of this European standard. Clauses 4 to 9 describe general requirements which relate to all areas of application mentioned. The following clauses contain specific requirements: Clause 10: Supply systems for a maximum operating operating pressure up to and including including 16 bar (distribution) Clause 11: 11: Supply systems systems for a maximum maximum operating operating pressure pressure greater greater than 16 bar (transmissi (transmission) on)

Page 5 EN 12732:2000 Clause 12: Metering, Metering, regulatin regulatingg and compres compressor sor stations stations Table 1 assigns the application areas to quality requirement categories as a function of the working pressure and pipe materials used. Table 1: Allocation to quality quality requirement categories Quality requirement category

A

Area of activity applies to

Pressure range and base material

Examples of use

 100 mbar Group 1 according to EN 2883:1992 R t 0,5   360 N/mm2



Mains and service pipes in gas distribution systems B

Pressure range and base material

Examples of use

> 100 mbar  5 bar Group 1 according to EN 2883:1992 R t 0,5   360 N/mm2 Mains and service pipes in gas distribution systems, pipework in stations

C

Pressure range and base material

Examples of use

> 5 bar  16 bar Group 1 according to EN 2883:1992 R t 0,5   360 N/mm2 Pipelines including pipework in stations and gas distribution systems

D

Pressure range or base material

> 16 bar* Group 1 to 3 according to EN 2883:1992

Examples of use Pipelines including pipework in stations and gas transmission systems Note: R t 0,5

specified minimum yield strength according to EN 10208-2:1996.

*

Pipelines having hoop stresses at design pressure up to 30 % of specified minimum yield strength and operated at a pressure up to 24 bar can be allocated to quality requirement category C by the pipeline operator.

Additional requirements may be specified when, for example -

the st strain on on pi pipeline ines and and syste stems;

-

the materials;

-

the line routing;

-

the design ign or the weldi lding techniqu ique

are considered critical. This European Standard specifies common basic principles for gas supply systems. Users of this European Standard should be aware that there can exist more detailed national standards and/or

Page 6 EN 12732:2000 codes of practice in the CEN member countries. This European Standard is intended to be applied in association with these national standards and/or codes of practice setting out the above-mentioned basic principles. In the event of conflicts in terms of more restrictive requirements in national legislation/regulation with the requirements of this standard, the national legislation/regulation shall take precedence. 2

Normative references

This European Standard incorporates by dated or undated reference, provisions from other publications. These normative references are cited at the appropriate places in the text and the publications are listed hereafter. For dated references, subsequent amendments to or revisions of any of these publications apply to this European Standard only when incorporated in it by amendment or revision. For undated references the latest edition of the publication referred to applies. EN 287287-1:1 1:1997 997

Approva Approvall testi testing ng of welder welderss - Fusio Fusionn weldin weldingg - Part Part 1: S Stee teels ls

EN 288-2 288-2:19 :1992 92

Specif Specificat ication ion and and approval approval of of welding welding proced procedure uress for metal metallic lic mater materials ials Part 2: Welding procedure specification for arc welding

EN 288-3 288-3:19 :1992 92

Specif Specificat ication ion and and approval approval of of welding welding proced procedure uress for metal metallic lic mater materials ials Part 3: Welding procedure tests for the arc welding of steels

EN 288-5 288-5:19 :1994 94

Specif Specificat ication ion and and approval approval of of welding welding proced procedure uress for metal metallic lic mater materials ials Part 5: Approval by using approved welding consumables for arc welding

EN 288-6 288-6:19 :1994 94

Specif Specificat ication ion and and approval approval of of welding welding proced procedure uress for metal metallic lic mater materials ials Part 6: Approval related to previous experience

EN 288-7 288-7:19 :1995 95

Specif Specificat ication ion and and approval approval of of welding welding proced procedure uress for metal metallic lic mater materials ials Part 7: Approval by a standard welding procedure for arc welding

EN 288-8 288-8:19 :1995 95

Specif Specificat ication ion and and approval approval of of welding welding proced procedure uress for metal metallic lic mater materials ials Part 8: Approval by a pre-production welding test

prEN prEN 288288-99

Spec Specififica icatition on and appr approv oval al of weld welding ing proc proced edur ures es for for met metall allic ic mater material ialss Part 9: Welding procedure test for on land and offshore site butt welding of transmission pipelines

EN 439:1 439:199 9944

Weld Weldin ingg cons consum umab ables les - Shie Shieldi lding ng gase gasess for for arc arc weld welding ing and and cutt cuttin ingg

EN 440: 440:19 1994 94

Weld Weldin ingg consu consuma mable bless - Wire Wire elect electro rode dess and dep depos osits its for for gas-s gas-shi hield elded ed meta metall arc welding of non-alloy and fine-grain steels - Classification

EN 473 473:19 :1993 93

Qual Qualififica icatition on and and cert certififica icatition on of of NDT NDT pers person onne nel.l. Gene Genera rall prin princip ciple less

EN 499:199 499:19944

Welding Welding consum consumable abless - Covere Coveredd elec electro trodes des for manual manual metal metal arc weldin weldingg of of nonnonalloy and fine-grain steels - Classification

EN 571-1 571-1:19 :1997 97

Non-de Non-destr struct uctive ive testi testing ng - Penetr Penetrant ant testi testing ng - Part Part 1: Genera Generall principl principles es

EN 583583-11

NonNon-de dest stru ruct ctiv ivee tes testiting ng - Ult Ultra raso soni nicc exa exami mina natition on - Par Partt 1: 1: Gen Gener eral al prin princi cipl ples es

EN 719 719:1 :199 9944

Weld Weldin ingg coor coordi dina natition on - Tas Tasks ks and and res respo pons nsib ibililititie iess

EN 729-1 729-1:19 :1994 94

Quality Quality requ require iremen ments ts for weldin weldingg - Fusion Fusion weldin weldingg of metall metallic ic mater materials ials Part 1: Guidelines for selection und use

EN 729-2 729-2:19 :1994 94

Quality Quality requ require iremen ments ts for weldin weldingg - Fusion Fusion weldin weldingg of metall metallic ic mater materials ials Part 2: Comprehensive quality requirements

EN 729-3 729-3:19 :1994 94

Quality Quality requ require iremen ments ts for weldin weldingg - Fusion Fusion weldin weldingg of metall metallic ic mater materials ials -

Page 7 EN 12732:2000 Part 3: Standard quality requirements EN 729-4 729-4:19 :1994 94

Quality Quality requ require iremen ments ts for weld welding ing - Fusio Fusionn welding welding of metal metallic lic mater material ialss Part 4: Elementary quality requirements

EN 756 756:19 :1995 95

Weld Welding ing cons consum umabl ables es - Wir Wiree elec electr trod odes es and and wire wire-f -flux lux comb combina inatition onss for for submerged arc welding of non-alloy and fine grain steels - Classification

EN 757:199 757:19977

Welding Welding consuma consumable bless - Covere Coveredd elec electro trodes des for manual manual metal metal arc-we arc-weldin ldingg of of high high strength steels - Classification

EN 758 758:19 :1997 97

Weld Welding ing con consu suma mable bless - Tubu Tubula larr core coredd elect electro rode dess for for meta metall arc arc weld welding ing wit withh or without a gas shield of non-alloy and fine grain steels - Classification

EN 760: 760:19 1996 96

Weldi Welding ng cons consum umab able less - Fluxe Fluxess for sub subme merg rged ed arc arc wel weldin dingg - Clas Classi sific ficat ation ion

EN 970:1 970:199 9977

NonNon-de destr struc uctitive ve exa exami mina natio tionn of fusio fusionn weld weldss - Vis Visual ual exam examina inatition on

EN 1290: 1290:199 19988

Non-de Non-destr structi uctive ve exami examinat nation ion of of welds welds - Magn Magnetic etic particl particlee examina examinatio tionn of weld weldss

EN 1418 1418:199 :19977

Welding Welding person personnel nel - Approv Approval al testin testingg of weld welding ing oper operato ators rs for for fusion fusion weldi welding ng and resistance weld setters for fully mechanized and automatic welding of metallic materials

EN 1435: 1435:199 19977

Non-de Non-destr structi uctive ve exam examinat ination ion of weld weldss - Radi Radiogr ograph aphic ic exami examinati nation on of of welde weldedd  joints

EN 1668: 1668:199 19977

Weldin Weldingg consuma consumable bless - Rods, Rods, wires wires and depo deposits sits for tung tungsten sten inert inert gas gas welding welding of non alloy and fine grain steels - Classification

prEN prEN 170 17088-11

Weld Welding ing - Basic Basic weld weld join jointt deta details ils in ste steel el - Par Partt 1: Pre Press ssur urize izedd comp compon onent entss

EN 1714: 1714:199 19977

Non-de Non-destr structi uctive ve exam examinat ination ion of weld weldss - Ultr Ultraso asonic nic exam examinat ination ion of weld welded ed  joints

EN 1775:19 1775:1998 98

Gas supply supply - Gas Gas pipew pipework ork for buildin buildings gs - Maximum Maximum operat operating ing pressu pressure re  5 bar Functional recommendations

EN 10002-1:1990 10002-1:1990 Metallic Metallic materials materials - Tensile testing testing - Part 1: Method Method of test EN 10204:1 10204:1995 995

Metalli Metallicc produc products ts - Types Types of inspecti inspection on docum document entss

EN 10208-1:1997 10208-1:1997 Steel pipes pipes for pipelines pipelines for combustible combustible fluids fluids - Technical delivery delivery conditions - Part 1: Pipes of requirement class A EN 10208-2:1996 10208-2:1996 Steel pipes pipes for pipelines pipelines for combustible combustible fluids fluids - Technical delivery delivery conditions - Part 2: Pipes of requirement class B EN 24063:1992 24063:1992

Welding, Welding, brazing brazing,, soldering soldering and braze-weldin braze-weldingg of metals - Nomencla Nomenclature ture of processes and reference numbers for symbolic representation on drawings (ISO 4063:1990)

EN 25817: 25817:199 19922

Arc-we Arc-welde ldedd joints joints in steel steel - Guidance Guidance on on quality quality level levelss for imperf imperfect ections ions (ISO 5817:1992)

EN 26520: 26520:199 19911

Classif Classificat ication ion of imperfe imperfecti ctions ons in metall metallic ic fusion fusion welds welds with explan explanati ations ons (ISO 6520:1982)

EN 27963: 27963:199 19922

Welds Welds in steel steel - Calibr Calibratio ationn block block No. 2 for ultr ultraso asonic nic examin examinati ation on of welds welds (ISO 7963:1985)

EN 29692:1994 29692:1994

Metal-arc Metal-arc welding welding with with covered covered electrode, electrode, gas-shielded gas-shielded metal-arc metal-arc welding welding and and gas welding - Joint preparations for steel (ISO 9692:1992)

EN 45001 45001:19 :1989 89

General General crit criteri eriaa for the the opera operatio tionn of testin testingg labora laborator tories ies

Page 8 EN 12732:2000 ISO 13686 3

Natural gas - Quality designation

Definitions an and a ab bbreviations

For the purposes of this standard, the following definitions apply. Symbols used in formulae are defined where they occur. 3.1 design temperature (DT): The temperature on which the design calculations are based. 3.2 gas: The gaseous fuel which is in a gaseous state at a temperature of 15 °C under atmospheric

pressure (1,013 25 bar absolute). 3.3 gas distribution system: The pipeline system including piping above and below ground and all

other equipment necessary to supply the gas to the consumer. 3.4 gas distributor: The private or public organization authorized to distribute gas to

consumers through a gas distribution system. 3.5 gas transmission: The activity intended to convey gas from one place to another through

pipelines in order to supply gas to distribution systems or to industrial consumers. 3.6 installation: Equipment and facilities for the extraction, production, chemical treatment,

measurement, control, storage or offtake of the transported gas. 3.7 maximum operating pressure (MOP): The maximum pressure at which a system can be operated

continuously under normal conditions. Note: normal conditions are: no fault in any device or stream. 3.8 national requirements: Requirements following from national legislation or more detailed

or stringent national standards 3.9 onshore pipeline: A buried and/or above ground pipeline including those sections laid in or

across inland lakes or water courses. 3.10 pipeline: A system of pipework with all associated equipment and stations up to the point of

delivery. This pipework is mainly below ground but also includes above ground parts. 3.11 pipeline components: The elements from which a pipeline is constructed. The following are

distinct pipeline elements:

 

-

pipe pipe incl includ udin ingg col coldd-fo form rmed ed bend bends; s;

-

fittings

EXAMPLE 1: reducers, tees, factory-made elbows and bends, flanges, caps, welding stubs, mechanical joints. -

fabr fabrica icatition ons, s, man manuf ufact actur ured ed from from elem elemen ents ts ref refer erre redd above above;;

EXAMPLE 2: manifolds, slug catchers, pig launching/receiving stations, metering and control runs. -

equipment;

EXAMPLE 3: valves, expansion joints, insulating joints, pressure regulators, pumps, compressors. -

pressure vessels.

3.12 pipeline operator: The private or public organization authorized to design, construct,

and/or operate and maintain the gas supply system. 3.13 pipework: An assembly of pipes and fittings.

Page 9 EN 12732:2000 3.14 pressure: The gauge pressure of the fluid inside the system, measured in static

conditions. 3.15 station: A plant or facility for the operation and/or processing of gas supply systems. 3.16 test pressure (TP): The pressure to which the gas supply system is subjected, to ensure that it can operate safely. 4

Quality system

If required by the pipeline operator, a quality system shall be applied to pipeline welding. A set of recommended quality requirements according to EN 729 is provided in Table 2, which specifies the requirements of EN 729 for the different categories as defined in Table 1. Table 2: Recommended quality quality requirements requirements Quality requirement category in accordance with Table 1

Requirement relating to:

A

B

C

D

+ +

+ +

* *

* *

*

*

-

-

+

+

+

*

welding technician

+

+

*

-

welding specialist1)

+

*

*

-

*

*

-

-

*

*

*

*

*

*

*

*

EN 288-3:1992 (welding procedure test)

+

+

*

*

EN 288-5:1994 (using approved welding consumables)

*

*

-

-

EN 288-6:1994 (previous experience)

*

-

-

-

+

+

*

*

EN 288-8:1995 (pre-production welding test)

+

*

*

*

prEN 288-9 (welding procedure test for site welding)

+

+

+

*

Quality system according to: EN 729-1:1994 and EN 729-2:1994(complete) EN 729-1:1994 and EN 729-3:1994 (standard) EN 729-1:1994 and EN 729-4:1994 (elementary) Welding coordination personnel: according to EN 719:1994: 

welding engineer 1)



Foreman welder with several years technical experience

Testing personnel according to EN 473:1993 Welding procedure specification (WPS): according to EN 288-2:1992 (except gas welding, procedure no. 311) Approval of welding procedures according to one of the following standards:

EN 288-7:1995 (standard welding procedures)

1)

1) This may be applicable applicable in category category D for small small projects projects or for materials materials with R t 0,5  360 N/mm². Explanation:

* + -

recommended optional not recommended

Page 10 EN 12732:2000 4.1

Welding contractors

If required by the pipeline operator, contractors shall demonstrate their ability to perform the work. Reference can be made to EN 729. 4.2

Welders

All welders shall be qualified for the work they are required to undertake. The qualification should be carried out in accordance with an appropriate specification (see clauses 10, 11 and 12). The pipeline operator may accept welders provided it can be demonstrated that they have produced welds of the required quality within the essential variables of the welding procedure. 4.3

Wel eldi din ng supe superrvi viso sorry/ y/co co--ordi ordina nattion ion per personn sonnel el

Welding tasks and responsibilities for welding shall be assigned to personnel with the appropriate experience and technical knowledge. Where a quality system is required, these personnel should be qualified to EN 719:1994. 4.4

Testing personnel

Destructive testing and non-destructive examination personnel shall be employed either by the pipeline contractor or by the pipeline operator or by an independent testing company. All companies providing such personnel should be certified. All non-destructive examination personnel shall be qualified for the duties they are to perform in accordance with EN 473:1993 or skill recognition by the pipeline operator. 5

Welding consumables

Welding consumables shall be in accordance with: Shielded metal arc welding Gas metal arc welding Flux-cored arc welding Shielding gases Submerged arc welding Fluxes for submerged arc welding

(prodedure no. 111) (procedures nos. 135, 141) (procedures nos. 114, 136) (prodedure no. 12) (prodedure no. 12)

: EN 499:1994 and EN 757:1997 : EN 440:1994 and EN 1668:1997 : EN 758:1997 : EN 439:1994 : EN 756:1995 : EN 760:1996

The numbering of the procedures given in brackets is in accordance with EN 24063:1992. All filler materials shall be certified as conforming to the relevant European Standard. Batch testing of the filler materials can be required by the pipeline operator. The certificates shall be in accordance with EN 10204:1995, type 3.1.B. The chemical composition of the deposited weld metal metal shall be compatib compatible le1) with the parent parent metal. metal. Unless Unless otherwise otherwise agreed, matching matching1) weld metal for girth girth welds shall be required. required. For the selection of consumables, the use of Table 3 is recommended. After filler material has been removed from its original package, it shall be protected or stored in accordance with the manufacturer's requirements, so that its characteristics or welding properties are not affected.

1)

 taking into account any specific property requirements

Page 11 EN 12732:2000 Table 3: Matching filler material requirements requirements Steel specification to EN 10208-1:1997 and EN 10208-2:1996** Rt 0,5

Filler material requirements to EN 440:1994/EN 499:1994/EN 757:1997 Rm

Designatio n

Designatio n

Rt 0,5 or R p 0,2 

Rm

KV

N/mm2

N/mm2

J

N/mm2

N/mm2

L 210

210

335 - 475

E35

355

440 - 570

L 245

245 - 440

415

E35

355

440 - 570

L 290

290 - 440

415

E35

355

440 - 570

L 360

360 - 510

460

E42

420

500 - 640

L 415 *

415 - 565

520

E46

460

530 - 680

L 450 *

450 - 570

535

E46

460

530 - 680

L 485 *

485 - 605

570

E50

500

560 - 720

L 555 *

555 - 675

625

E55 E62

550 620

610 - 780 690 - 890

47/32

NOTES: *

For For wal walll thi thick ckne ness sses es > 8 mm a low lower er stre streng ngth th cons consum umab able le can can be be use usedd for for the the roo roott and and hot pass.

**

Fitt Fittin ingg mat mater eria ials ls are are to to be be spec specififie iedd in in acc accor orda dance nce with with the appr approp opri riat atee EN EN stan standar dard. d.

R t 0,5

Specified Specified minimum yield strength strength measured measured in N/mm2 .

R m

Tensile strength according to EN 10208-2:1996 measured in N/mm2 .

R p 0,2

0,2 % proof strength according to EN 10002-1:1991 measured in N/mm2 .

KV 

Impact test value (Charpy-V method) obtained for full size specimen (average/individual) measured in Joule.

6

Production welding

6.1

General requirements

All welding shall comply with the approved welding procedure specification. 6.1.1

Working area

The working space shall enable adequate access to the work area in order to provide a safe environment and to allow satisfactory production and testing of a weld joint. 6.1.2

Layout of weld joints

Weld joints, in particular tie-ins, shall be arranged and designed in a way suited to the planned welding and testing technique. The placement of tie-in welds is particularly important. 6.1.3

Types of of we weld jjo oints

Unless otherwise agreed, pipes and pipeline fittings shall be connected using butt-welded  joints.

 

Page 12 EN 12732:2000 6.1.4

Joint e ed dge pr preparation

Joint edge preparations shall comply with the appropriate EN standards and the approved welding procedure. Appropriate EN standards include prEN 1708-1 and EN 29692:1994. The choice of joint configuration shall take into account the welding technique, the welding position and the accessibility of the joint. 6.1.5

Weld s sp pacing

Weld spacing shall be sufficient to ensure the integrity of the joint. 6.1 .1.6 .6

Dif Differ ferent ent wa wall thic thickn knes esse ses s

When pipes of different wall thicknesses have to be joined together, special precautions shall be taken to avoid stress concentration and weld defects. When butt welding pipework of different wall thicknesses has to be performed, 6.2.2 below and/or prEN 1708-1 shall apply. Annex C of this Standard should also be observed. 6.1 .1.7 .7

Pipe ipe branc ranch hes and and nozz ozzle les s

Forged fittings are preferred. Weld-on branches and nozzles are allowed. 6.1.8

Laminations

Additional precautions can be required where welding is performed in the area of laminations. A recommended procedure for checking for laminations is given in Annex B. 6.1.9

Butt we welded cr cross jo joints

Unless otherwise agreed, butt welded cross joints shall be avoided. 6.2

Joint preparation

6.2.1

Pipe end preparation

To ensure that the required weld quality is achieved, all necessary details concerning the joint preparation have to be laid down in the welding procedure specification. 6.2.2

Alignment of of th the jo joints

Alignment clamps shall be used where possible; the details and how they are to be used shall be included in the welding procedure specification. Root misalignment is acceptable as far as it is not affecting the integrity of the joint. For recommendations see Annex G. Misalignment of pipes and pipelines made of steel grades with a minimum specified yield strength R t 0,5 less than or equal to 360 N/mm2 which is outside the tolerance range of the tables given in Annex G may be compensated for by deformation, if agreed by the pipeline operator, by the use of special equipment or by transition pieces. The heat-treatment condition of the material shall be taken into account. NOTE: The strength of thermomechanically treated as well as quenched and termpered steels is, in some cases, permanently reduced by heating to temperatures above 580 C.

Page 13 EN 12732:2000 Root misalignment of pipes and pipelines of different wall thicknesses and made of steel grades with a specified minimum yield strength R t 0,5 greater than than 360 N/mm2 which is outside outside the tolerance range of the tables given in Annex G shall be compensated for by using transition pieces. During correction of excessive root misalignment, measures shall be taken to avoid defects. Examples of permissible weld configurations are given in Annex C. 6.3

Preheating

Preheating shall be applied in accordance with the welding procedure specification. 6.4

Tacking

Whenever tack welds are used, they shall be made using the welding procedure designed for the root pass. They shall be distributed equally around the circumference. The tacks shall be free from cracks. Cracked tacks shall not be welded over, and shall be ground out and rewelded. 6.5

Welding

Precautions shall be taken to:

6.6

-

minimiz minimizee hydrog hydrogen en pickpick-up up in in the work, work, in particu particular lar for steels steels which which are sensiti sensitive ve to cold cracking;

-

avoid condensation;

-

avoi avoidd air air move moveme ment ntss in the the pipe pipe;;

-

avoi avoidd unc uncon ontr trol olle ledd ele elect ctri rica call cur curre rent nt;;

-

minimi imize ma magnetic effect ects;

-

avoid cold cracking;

-

avoid arc strikes. Actions after welding

After the weld is completed, weld spatter shall be removed. The weld surface shall be cleaned of slag. The cooling process shall not be accelerated beyond the rate specified in the welding procedure specification. Where air temperatures are below 5 C and/or poor climatic conditions like wind or rain prevail, or if the pipeline operator requires it, the weld joint shall be protected against excessively rapid cooling. Stress-relief heat treatment may be necessary. 6.7

Repair of weld defects

Weld joints which do not meet the specified requirements shall be repaired or cut out. On each weld joint which requires repair, the faulty area shall be clearly marked. marked. The marking shall not be removed until the defect has been repaired and the repair work has been inspected. If more than 20 % of the total weld exhibits defects requiring repair, or if several defective weld sections amount to this length overall, the weld joint in question shall be cut out and rewelded unless otherwise agreed by the pipeline operator.

Page 14 EN 12732:2000 Weld joints with cracks shall be completely cut out. However, in special cases, and where approved by the pipeline operator, cracks may be repaired provided the cause of the crack has been established beyond doubt and provided it is confirmed that the fault has been correctly identified. Repairs shall be retested non-destructively using suitable techniques. If non destructive testing of a repair reveals that the area still has unacceptable indications, the weld shall be cut out and rewelded unless otherwise agreed by the pipeline operator. 7

Special procedures

Before special procedures as given below are carried out, the type and scope of testing of the weld joint shall be specified. The scope of the testing shall be in accordance with 8.2. The testing technique used will depend on the type and dimension of the weld pieces. 7.1

Attachment of of s sttructural p pa arts

Structural parts shall be attached using a continuous weld. Intermittent welds shall not be used. When welding structural parts onto components made of steel grades with specified minimum yield strength greater than 360 N/mm2 , special measures shall be employed which take account of the material characteristics. EXAMPLE: buttering with low-yield/low-hydrogen electrodes. These precautions shall be specified in the welding procedure specification. 7. 7.2 2

Atta Attach chme ment nt of ca cath thod odic ic prot protec ecti tion on conn connec ecti tion ons s

Electrical bonds to the pipe surface must be made with a welding or brazing method which does not alter the integrity of the metal. It shall be demonstrated by a performance test that the metallurgical structure is not adversely affected. To qualify for making cathodic protection connections, the operator's skill shall be tested under site conditions before work begins. When cable connections are made to the pipeline, the adhesion of the weld shall be verified. Recommendations for brazing and aluminothermic welding of anodic bonding leads are given in Annex H. 7. 7.3 3

Hot Hot tapp tappin ing g and and othe otherr wel weldi ding ng work work on pres pressu suri rize zed d pipe pipeli line nes s and and sys syste tems ms

All hot-tap welding procedures shall include the following additional requirements: Hot-tap welding shall only be carried out after sufficient research and development to ensure the safety of the operation and the correct mechanical properties of the weld. Prior to the execution of welding work on pressurized pipelines and systems, the pipeline operator shall establish whether the design, the material and the construction condition of the pipeline allows welding under operating pressure. Critical aspects for hot-tap welding shall be included in the welding procedure specification and shall be subject to approval by the pipeline operator. A list of critical aspects is given in Annex D for information. Welding sleeves and split-tees greater than DN 50 nominal size for use on pipelines made of steel grades with specified minimum yield strength greater than 360 N/mm2 shall be of the split fullencirclement type or shall incorporate additional local reinforcement.

Page 15 EN 12732:2000 The longitudinal seam weld of a split attachment shall not be allowed to impinge on the pipe wall of the pressurized pipe. Where the attachments are of steel grades with specified minimum yield strength greater than 360 N/mm2 or are designed so that longitudinal contraction stresses can cause deformation, the first circumferential fillet weld shall be completed before the second is started. The cooling rate shall not be increased. Where tacks for installation purposes are necessary in the area of the second circumferential weld these shall be ground out completely. 8

Inspection of the weld joint

8.1

General

Weld quality shall be ensured by inspection of the welds using destructive tests and/or nondestructive examination. The results of these tests shall be documented. Non-destructive examination shall be carried out in accordance with approved procedures and destructive testing shall be as for the original welding procedure, i.e. EN 288-3:1992 or prEN 288-9. 8.2

Scope of inspection

The inspection shall comprise inspection during welding, final visual inspection, nondestructive examination and destructive testing. The minimum extent of non-destructive examination in respect of the quality requirement category and the type/position of the weld joint is given in Table 4. The pipeline operator shall select which welds are to be tested. Where less than 100 % non-destructive examination is performed and the quality of the weld joint does not meet the requirements, further welds shall be examined to determine the extent of the problem. The cause of the fault shall be eliminated. Except when otherwise agreed, two further welds shall be inspected for each rejected weld. Table 4: Minimum extent of non-destructive non-destructive examination examination Quality requirement category in accordance with Table 1

A

B

C

Type/position of the weld joint

Circumferential welds, branches, nozzles and fillet welds; longitudinal seams Unconcealed pipe spans; pipelines on bridges, pipeline sections crossing railways, navigable waterways or landing strips/runways Circumferential welds Branches, nozzles and fillet welds Longitudinal seams Unconcealed pipe spans; pipelines on bridges, pipeline sections crossing railways, major roads and motorways, navigable waterways or landing strips/runways Circumferential welds Branches, nozzles, fillet welds Longitudinal seams Weld joints not included in the pressure test Unconcealed pipe spans; pipelines on bridges, pipeline sections crossing railways, major roads and motorways, navigable waterways or landing strips/runways

Visual examination by welding supervisor

Radiography or ultrasonic examination (see note 1)

See note 2

See note 2 See note 3

100 %

See note 4

See note 2 See note 2

See note 2

100 % 100 %

10 % See note 4

20 % 10 0 % 100 % 100 %

10 % 100 % 100 %

100 %

100 %

Surface crack   test

See note 2

10 %

continued

Page 16 EN 12732:2000

Table 4: Minimum extent of non-destructive non-destructive examination examination (continued) Quality requirement category in accordance with Table 1

D

Type/position of the weld joint

Circumferential welds Branches, nozzles, fillet welds

Longitudinal seams Sweepolets Weld joints not included in the pressure test If pipelines/units are laid or installed in built-up areas Unconcealed pipe spans; pipelines on bridges, pipeline sections crossing railways, major roads and motorways, navigable waterways or landing strips/runways Note 1: The proportion of both techniques shall be agreed.

Visual examination by welding supervisor

Radiography or ultrasonic examination (see note 1)

100 % 100 %

20 % (See note 7)

100 % 100 %

Surface crack   test

20 % (see note 5)

100 %

100 %

100 % (see note 6) 100 %

100 %

100 %

Note 2: Representative random sample on the basis of the total number of weld joints made by a welder during the course of one year. Note 3: One destructive test of field weld per year by means of tensile and/or bending test for welders qualified only for gas welding (procedure no. 311) or only for fillet welds. Note 4: The pipeline operator shall specify the extent of non-destructive examination taking into account the design conditions, for example: - externa externall loads in additi addition on to interna internall pressure pressure;; - supports; - expansi expansion on due to temper temperatu ature. re. Note 5: Where welds with incomplete penetration are used, the pipeline operator can require 100 %. Note 6: Seams shall be tested 100 % by two different inspection techniques. Note 7: For branches and nozzles, consideration should be given by the pipeline operator to these methods. Concluded 8. 8.3 3

Nonon-dest destru ruct ctiv ive e ex exam amin inat atio ion n

The method or combination of methods for visual and non-destructive examination of the welds shall be specified by the pipeline operator. Prior to commencement of welding, the nondestructive examination procedures shall be submitted to the pipeline operator for approval. In special cases, one inspection test method may be replaced by another. Other forms of non-destructive examination can be required, depending on the material used, the design and/or the welding technique. Visual examination of welds should be carried out in accordance with EN 970:1997. Supplementary recommendations are given in Annex E.

Page 17 EN 12732:2000 Radiographic examination shall be carried out in accordance with EN 1435:1997. If not otherwise agreed by the pipeline operator, the image quality class shall be class A for categories A through C and class B for category D. The test laboratory contracted for radiographic work should be accredited to EN 45001:1989. Ultrasonic examination shall be carried out in accordance with EN 583-1 and EN 1714:1997. Supplementary recommendations are given in Annex F. In procedures nos. 114, 135 and 136 in accordance with EN 24063:1992, the following additional requirements shall be applicable. In special cases supplementary ultrasonic examination can be required. EXAMPLE: When short-circuit welding and/or where large thicknesses are involved. In the first instance, the extent of this supplementary ultrasonic examination shall be 25 %. Depending on the results of this examination, the pipeline operator can either: -

requ requir iree supp supple leme ment ntar aryy exam examin inat atio ionn or

-

redu reduce ce the the ext exten entt of of this this exam examin inat atio ion. n.

Dye-penetrant examination shall be carried out in accordance with EN 571-1:1997. Magnetic-particle examination shall be carried out in accordance with EN 1290:1998. The flow chart in Figure 1 identifies where the criteria for execution, extent and acceptance for various non-destructive examination methods can be found in this and other documents.

Non-destructive examination procedures according to 8.3

Application Supply systems MOP < 16 bar Quality requirement cat. A, B, C

Supply systems MOP > 16 bar Quality requirement cat. D

Stations Quality requirement cat. A, B, C, D

Visual examination

Magnetic particle examination

Dye penetrant examination

Radiographic examination

Ultrasonic examination

Procedure: EN 970:1997 Annex E

Procedure: EN 1290:1998

Procedure: EN 571-1:1997

Procedure: EN 444:1994 EN 1435:1997

Procedure: prEN 583-1 EN 1714:1997 Annex F

Criteria: Annex E Annex G

Criteria: Annex G

Criteria: Annex G

Criteria: Annex G

Criteria: Annex G Table G.3

Figure 1: Non-destructive examination examination procedures and acceptance criteria

Page 18 EN 12732:2000 8.4

Time of inspection

All non-destructive examination shall be carried out before pressure testing, with the exception of final tie-in welds which are not subjected to the pressure test (”golden welds”). 8.5

Acceptance criteria

The pipeline operator shall specify the acceptance criteria. The acceptance criteria given in Table G.1 for radiographic findings and in Table G.3 for ultrasonic findings are based on workmanship criteria. The pipeline operator can use EPRG guidelines (see Annex G.2) or alternative acceptance criteria based on fracture mechanics analysis and fitness-for-purpose criteria, provided they are fully documented and based on a proven safe approach. The results of the radiographic examination shall meet the acceptance requirements which are given in clauses 10 and 11. Weld defects detected by means of ultrasonic examination shall be evaluated in accordance with the requirements of Table G.3. The acceptance requirements for alternative examination methods shall be determined from case to case. 8. 8.6 6

Rec eco ordi rding of tes test resu result lts s

A clear relationship shall exist between the examination report, the radiographs and the weld under examination, and shall be indicated in a sketch or pipe logbook. 9

Documentation

9.1

General

The documentation is intended to prove that the welding requirements and test provisions according to this standard are fulfilled. This documentation shall be compiled in such a way that traceability is ensured. 9. 9.2 2

Archiv chivin ing g req requir uiremen ementts

Documentation shall be archived in accordance with the pipeline operator's policy. 10

Specif Specific ic rrequ equire iremen ments ts for for gas gas supp supply ly s syst ystems ems up to to and and inclu includin ding g 16 bar MOP MOP (distribution)

10.1

General

This clause contains specific requirements for the welding and inspection of gas supply systems up to and including 16 bar MOP (distribution). Table 1 defines the quality requirement categories.

Page 19 EN 12732:2000 10. 2

Welders

Welders shall be qualified in accordance with EN 287-1:1997, taking into account the essential variables as laid down in clause 6. For acceptance criteria in accordance with EN 287-1:1997 reference can be made to Annex G.1. For gas welding (procedure no. 311) of pipes of category A, welders' qualification requirements are to be defined by the pipeline operator. Welders employed in the installation of buried pipelines shall have passed their welding examination under site conditions. This requirement is deemed to have been fulfilled if the examination is conducted in an area which simulates a pipe trench of the following dimensions: -

maximum length:

1,5 m

-

maximum spacing between pipe wall and trench bottom:

0, 4 m

-

maximum spacing between pipe wall and trench wall:

0,5 m

Welders certificate shall clearly indicate, by reference to this standard, that the welders qualification test has been performed under the conditions mentioned above. 10 10.3 .3

Weld We ldin ing g supe superv rvis isor ory y pers person onne nell

Welding specialists qualified to EN 719:1994 are qualified to act as welding supervisors monitoring welding work on site. For welding work in quality requirement categories A and B, the welding supervisor can be a foreman welder with several years specialized technical experience. 10.4 10.4

Prod Produc ucti tion on weld weldin ing g

If feasible, working pits or bell holes should be constructed in the pipe trench. They should have a minimum free length of 1,5 m at the weld area. The distance from pipe to bell hole bottom should be not less than 0,4 m and from pipe to trench wall not less than 0,6 m. Bell holes shall be kept free of water during welding work. Segmental cuts up to 7,5 (tangents up to 15) are permitted for pipelines and systems for quality requirement categories A and B. Segmental cuts up to 2,5 (tangents up to 5) are permitted for pipelines and systems in quality requirement category C. In areas subject to ground movements and at unconcealed pipe spans and at pipelines on bridges, changes of direction using segmental cuts shall not be permitted. 10.4 10.4.1 .1

Join Jointt prep prepar arat atio ion n

Socket joints according to prEN 1708-1 are allowed for all diameters in quality requirement categories A and B, if approved by the pipeline operator. Bell and spigot, socket or sleeve welds shall be set up so that the root gap of the fillet weld is the minimum possible. No tools with sharp edges shall be used during this process. Where the end of the socket shall be forged, it shall be heated to a forging temperature suitable for the material quality. The welding of alignment aids and similar temporary attachments onto pipelines should be avoided. If necessary, alignment aids and similar temporary attachments can be used with the approval of the pipeline operator. 10.4.2

Welding

All welding, including repairs and welding of patches for repair, shall be carried out in accordance with the approved welding procedure specification.

Page 20 EN 12732:2000 10.5 10.5

Acce Accept ptan ance ce requi require reme ment nts s

For radiographic examination reference can be made to Table G.1 or Table G.2. For ultrasonic examination reference can be made to Table G.3. 10.6 10. 6

Requir Requireme ements nts for rec record ords s and docume documenta ntatio tion n

The following documents should be made available: a)

materi material al cert certifi ificate cate (only (only for for cate categor goryy C); C);

b)

weld weldin ingg proced procedur uree specif specific icat ation ion;;

c)

weldi welding ng pro proce cedu dure re app appro rova vall reco record rd;;

d)

pipe pipe log logbo book ok (on (only ly for for cat categ egor oryy C); C);

e)

weldin weldingg proc procedu edure re qualifi qualificati cation on record record;;

f)

nonnon-de dest stru ructi ctive ve exa examin minat atio ionn repo report rts; s;

g)

radiographs;

h) pipe pipe rout routin ingg (as (as bui builtlt). ). 11

Specif Specific ic requi requirem rement ents s for gas gas suppl supply y system systems s greate greaterr than than 16 bar bar MOP MOP (trans (transmis missio sion) n)

11.1

General

This clause contains specific requirements for the welding and inspection of gas supply systems greater than 16 bar MOP (transmission). These welding aspects shall be taken into account in order to reduce the risk of weld defects. Table 1 shows the area of application. 11.2

Welders

Welders can be qualified according to EN 287-1:1997 or in accordance with a standard of the pipeline operator. An example is given in Annex A. If the pipeline operator has justifiable doubts regarding the skill of a welder in respect of the welding work to be performed, requalification with additional requirements can be required. 11 11.3 .3

Weld We ldin ing g supe superv rvis isor ory y pers person onne nell

The monitoring of welding work on site can be delegated from the welding supervisory personnel in charge according to clause 4, Table 2, to a welding specialist qualified to EN 719:1994. 11.4 11. 4

Qualif Qualifica icatio tion n of weldin welding g proced procedure ures s

The pipeline operator shall specify the requirements for the approval of the welding procedure according to the relevant part of EN 288. Table 2 gives an overview of the recommended requirements. The welding procedure shall be in accordance with EN 288-2:1992 and be submitted to the pipeline operator for approval prior to commencement of welding.

Page 21 EN 12732:2000 For welding work on materials which have not been qualified by standard procedures according to EN 288-7:1995, as well as for special designs, qualification of the procedure shall be carried out according to EN 288-3:1992 or, as specified by the pipeline operator, according to EN 288-8:1995. EXAMPLE 1: cable connections for cathodic protection. EXAMPLE 2: work on ”live-lines”. EXAMPLE 3: installation aids. 11.4.1

Testing Testing requiremen requirements ts for welding welding procedure procedure qualificat qualification ion

As transmission pipelines are subject to external forces, care shall be taken to ensure that weld defects cannot become critical. For grades L 485 and L 555 according to EN 10208-2:1996, matching of base and filler materials is required and the use of Table 3 is recommended. Testing should be carried out in accordance with EN 288-3:1992 or prEN 288-9, as appropriate. However. depending on service and/or conditions to be experienced by the pipeline, more stringent requirements or additional tests can be specified by the pipeline operator. EXAMPLE 1: overmatching of consumables. EXAMPLE 2: impact testing. EXAMPLE 3: transverse tensile testing. EXAMPLE 4: all-weld-metal tensile testing. 11 11.4 .4.2 .2

Impac mpactt tes testting ing

In addition to prEN 288-9 and EN 288-3:1992, the following requirements are prescribed for the weld metal notched in the centre of the weld and in the heat-affected zone. Minimum impact energy: - Steel grades grades with with specified specified minimum minimum yield yield strength strength less or equal to 360 N/mm N/mm2 Average 27 Joule (J) Individual 20 Joule (J) - Steel grades grades with with specified specified minimum minimum yield yield strength strength greater greater than than 360 N/mm N/mm2 Average 40 Joule (J) Individual 30 Joule (J) NOTE: If the EPRG rules are specified by the pipeline operator, the Charpy-V requirements of 40 Joule average, 30 Joule individual shall be used (see Table G.2). In addition to the above-mentioned standards, testing is required for all pipe wall thicknesses greater than 5 mm. Where subsidiary tests are necessary because of limited wall thickness, the measured impact energy (KV P) shall be stated together with the test piece cross-section (S P ) measured under the notch in square millimetres. For comparison with the requirements specified above, the measured energy shall be converted to the impact energy KV  (in  (in Joules) using the formula:

KV 

8 × 10 × 

S P

KV P

Page 22 EN 12732:2000 where: KV  KV P S P

is the impact energy for the full-size specimen, in Joules; is the measured impact energy, in Joules; is the cross-section measured under the notch, in square millimetres.

The specimen shall be as thick as possible. The verification test temperature shall be equal to the minimum design temperature or, if agreed, to the minimum exposure temperature which can occur. 11 11.4 .4.3 .3

Tran Transv sver erse se tens tensil ile e test test

The tensile strength of the joint, including the fusion zone of each specimen, shall be equal to or greater than the specified minimum tensile strength of the pipe material. If the specimen breaks in the weld metal, it shall be considered acceptable provided that the specified minimum tensile strength of the pipe material has been achieved. 11 11.4 .4.4 .4

AllAll-we weld ld-m -met etal al ten tensi sile le tes testt

If an all-weld-metal tensile test is specified (information in addition to that contained in the 3.1.B certificate to EN 10204:1995), the test specimen and the tests should be in accordance with the appropriate EN standard. The yield strength should be equal to or higher than the specified minimum yield strength of the parent metal. 11.5 11.5 11.5 11.5.1 .1

Prod Produc ucti tion on weld weldin ing g Gene Genera rall requi require reme ment nts s

If feasible, working pits or bell holes should be constructed in the pipe trench. They should have a minimum free length of 1,5 m at the weld area. The distance from pipe to bell hole bottom should be not less than 0,4 m and from pipe to trench wall not less than 0,6 m. Bell holes shall be kept free of water during welding work. Pipes, pipeline parts and other components which require marking (in accordance with EN 10204:1995) shall be restamped or remarked next to the cutting line prior to cutting. The minimum length of a single pipe to be welded into a pipeline shall be 0,5 times DN. Where forged fittings are used in a tie-in situation, the fittings should have pipe-pups welded to them before welding into the line so that the final tie-in is a pipe-to-pipe joint. Segmental cuts shall be limited to 1,5 (tangents up to 3). When segmental cuts are used only manual welding shall be allowed. In areas subject to ground movements and at unconcealed pipe spans and at pipelines on bridges, changes of direction by segmental cuts are not permitted. 11.5 11.5.2 .2

Join Jointt prep prepar arat atio ion n

Absence of laminations shall be proven by ultrasonic testing or other appropriate means, before branches, nozzles and structural parts are welded onto pipelines or other components and before cutting is carried out (see Annex B). Pipes and pipeline components shall be clamped in such a way that strain due to movement on the weld during welding is avoided. The welding of alignment aids and similar temporary attachments onto pipelines shall not be acceptable.

Page 23 EN 12732:2000 11.5.3

Welding

During welding, particular attention shall be paid to: - preheat temperature; - the time lapse between runs; - the number of runs before work can be interrupted; - the total time for weld completion; - the welding energy for root pass for downhill downhill welding with cellulosic electrodes. In cases where tie-in welds are not subjected to hydrostatic testing and when welding steel grades from Groups 2 and 3 according to EN 288-3:1992, cellulosic electrodes shall be permitted only at the discretion of the pipeline operator. 11 11.5 .5.4 .4

Repa Repair irs s of weld weld defe defect cts s

When an external repair of the root is carried out, it shall be made to a qualified procedure. If a test of a repair weld shows that the area is still defective, the seam shall be cut out and rewelded unless otherwise agreed by the pipeline operator. 11.6 11. 6

Destru Destructi ctive ve testin testing g of of prod product uction ion welds welds

The minimum number of production welds to be tested shall be in accordance with Table 5. Welds shall be tested in accordance with EN 288-3:1992 or, if required by the pipeline operator, in accordance with prEN 288-9. Table 5: Minimum number of production test welds as function of pipeline length

11 11.7 .7

Pipeline length L km

Number of samples

1 < L  10 10 < L  50 L > 50

1 2 2 plus 1 further sample per length of 50 km or part thereof

Acce Accept ptan ance ce requ requir irem emen ents ts

For radiographic examination reference can be made to Table G.1 or Table G.2. For ultrasonic examination reference can be made to Table G.2 or Table G.3. When welding level grades from Groups 2 and 3 according to EN 288-3:1992 with wall thicknesses greater than 10 mm which are not pressure-tested, then welds shall also be ultrasonically examined (see Table 4, note 6). In case of welding with cellulosic electrodes, this examination shall be carried out not sooner than 24 hours after the welding has been completed unless soaking is performed. In case the pipeline operator uses EPRG guidelines (see Annex G.2) or alternative acceptance criteria based on fracture mechanics analysis and fitness-for-purpose criteria it is recommended to perform the non-destructive testing of the welds by combination of two different inspection techniques.

Page 24 EN 12732:2000 11.8 11. 8

Requir Requireme ements nts for rec record ords s and and docum document entati ation on

Traceability of documents for each single weld joint shall be compiled which shall include identification of the welders employed and the welds produced by them. The documents as listed below should be verified and checked prior to commissioning. Records and documentation should include: a) requirements of the relevant authorities; b) approval on installation; c) contractual conditions; d) planning and execution documentation; EXAMPLE 1: specifications, welding instructions, calculations and computations, design plans, part lists. e) approval/certificate of suitability, also for subcontractors and suppliers if applicable; f) qualification of welding personnel: 1) qualification of welding supervisory body according to EN 719:1994 and area of responsibility of welding supervisory body; 2) qualification of welders (welder's certificate); 3) qualification of operators of welding machines according to EN 1418; g) qualification of test personnel: 1) qualification of test supervisory body according to the appropriate EN standard and area of responsibility of test supervisory body; 2) qualification of testers according to the appropriate EN standard and duties of testers; h) proof of the suitability of the welding method according to EN 288 series; i) certificates, authorizations, delivery confirmation for semi-finished products and components;  j) written records on the execution of heat-treatment operations; k) test records: 1) non-destructive examination and destructive tests; 2) soundness and strength tests; l) report on special features of construction work as well as on special measures; EXAMPLE 2: work under difficult conditions such as adverse, cramped conditions. m) inventory and location of components; n) pipe logbook; o) if applicable, conformity declaration by the welding contractor, also by subcontractors and suppliers; p) approval records.

Page 25 EN 12732:2000 12

Specif Specific ic rrequ equire iremen ments ts for for mete meterin ring, g, regu regulat lating ing and compre compresso ssorr stati stations ons

12.1

General

This clause contains specific requirements for welding on and inspection of stations. Table 1 defines the quality requirement categories. 12.2 12.2

Spec Specif ific ic req requi uire reme ment nts s

It is recommended that the same requirements are used for stations as for the general pipeline construction, according to the quality requirement category. The requirements relating particularly to construction below ground level are excluded. These include: - examination of welders under site conditions (see 10.2 and 11.2); - general requirements for working pits or bell holes (see 10.4, 11.5.1); - destructive testing (see 11.6). Additional measures can be required in certain circumstances. EXAMPLE 1: When design temperature or vibration are considered critical. EXAMPLE 2: When special materials are used for pipes and /or pipework. EXAMPLE 3: When different grades of steel are being welded together.

Page 26 EN 12732:2000 Annex A (informative) Qualification for pipeline welders (Girth welds and branch connections)

A.1

General

In the case of fully mechanised processes, before execution of approval test, welders should be examined about functional knowledge appropriate to the welding unit as specified in Annex B of EN 1418:1997. A.2 A.2

Exec Execut utio ion n of appr approv oval al test test

a) The test test pipes to to be welded welded should should be of pipeline pipeline steel accordi according ng to EN 10208. b) Weldi Welding ng tech techni niqu quee shoul shouldd be: be: - single side no backing (ss nb) or - single side with backing (ss mb) or - both side (bs). c) Welding shall be performed performed in an area which which simulates simulates a pipe pipe trench trench of the the following following maximum maximum dimensions: -

trench length:

1,5 m

-

spacing between pipe wall and trench bottom:

0,4 m

-

spacing between pipe wall and trench wall:

0,5 m

d) For pipes pipes less than than DN 400 the welder welder should should complete complete the the whole whole circumferenc circumferencee of a joint. joint. e) For pipes equal or greater than DN 400 the welder should weld half the circumference of the  joint (12 to 6 o‘clock position) in which case h e is qualified to weld over the entire circumference. A.3

Range of of te test pi pieces

Pipeline welders shall perform a test for the particular type of application. Parameters could be: -

Welding process;

-

Welding po position;

-

Fille Fillerr mate materi rial al (inc (includ ludin ingg combi combina natio tions ns); );

-

Pipe material.

For an overall qualification for all diameters the welder shall perform as a minimum two different diameters in at least two positions. EXAMPLE: the combinations PC/PF or PC/PG according to EN ISO 6947:1997. For (cellulosic or basic) downhill or flux cored arc welding the diameters shall be : - DN 150 with a wall thickness in the range from 4,5 mm to 9 mm and - 400  DN  800 with wall thickness > 10 mm.

Page 27 EN 12732:2000 For other processes the dimensions should be: - 50  DN  150 with wall thicknesses between 3,6 mm and 9 mm and - 400  DN  800 with wall thickness > 10 mm. Additionally, one DN 50 weldolet or equivalent in position PC on a pipe of at least DN 400 should be welded. A.4

Preparation

Filler material shall be approved, certified and commercially available. Welding shall be carried out according to an approved welding procedure specification. 10.2 should be maintained. A.5

Exe xecu cuttion ion of of tes testt wel weldi din ng

The pipeline operator shall nominate an examiner. Unless otherwise agreed a notified body shall examine the qualification. The welder shall identify himself with an appropriate document. Clear identification marks shall be present on the pipe before welding starts. Repairs during welding are not allowed. A.6

Inspection

Both non-destructive examination and mechanical testing are required. After finishing welding, the examiner shall execute visual examination. The quality should meet the requirements of Annexes E and G.1. All test pieces shall be X-rayed according to EN 287-1:1997 and examined according to table G.1 quality requirement category D. For automatic processes (metal active gas (MAG) welding/ metal inert gas (MIG) welding) ultrasonic examination shall be carried out instead of radiography, when the wall thickness exceeds 8 mm. Weld quality should meet the requirements of Annex G.3 of this standard. The weldolet shall be subjected to Magnetic Particle examination only. A.6. A.6.1 1 Test Testin ing g girth girth wel welds ds

Mechanical testing shall be performed on each part of the joint welded in the relevant welding position according to EN 287-1:1997. The four bend or fracture test pieces of 400  DN  800 test weld shall be taken from the 1, 3, 4 and 5 o‘clock positions. For the small diameter welder qualification test the weld test pieces shall be taken in accordance with EN 287-1:1997. For cellulosic welds, a degassing heat treatment of 250 °C for up to 10 hours is recommended on transverse bend test specimens. A.6. A.6.2 2 Test Testin ing g weldo weldole lets ts

Four macro specimens shall be taken from the fillet weld. A.7

Approval ra range

A.7.1 Materials

When welding the combination as mentioned above the welder is qualified according to this standard for welding all pipelines in all diameters, wall thicknesses and material according to EN 10208 for the relevant procedures and positions. The welder is only qualified to use the type of filler material for which he has been approved. EXAMPLE: Cellulosic only qualifies cellulosic.

Page 28 EN 12732:2000 A.7. A.7.2 2 Dime Dimens nsio ions ns

When separate qualifications are performed the range is as follows: -

DN 50 quali qualifie fiess all diame diameter terss up to and and includi including ng DN 100 100 (categ (category ory:: small small diamet diameter) er);;

-

DN 150 150 qualifi qualifies es all diam diameter eterss between between DN DN 100 and and up to and and includ including ing DN DN 250 (cate (categor gory: y: medium diameter);

-

DN 400 400 quali qualifie fiess equal equal to or great greater er than than DN DN 250 250 (categ (category ory:: large large diame diameter ter). ).

A.7. A.7.3 3 Tech Techni niqu que e

-

Single Single side side (ss) (ss) qualifi qualifies es single single side side and and both side side (bs) (bs) and and single single side side with with backing backing (ss (ss mb).

-

Single Single side side with with backi backing ng (ss (ss mb) mb) only only qualif qualifies ies sing single le side side with with backi backing. ng.

-

Both Both side side (bs) (bs) quali qualifies fies both both side side and and single single side side with with back backing ing (ss (ss mb). mb).

A.8

Duration of of v va alidity

The duration of validity for the certificate is six months. Non-destructive testing (NDT) records shall be maintained according to small, medium and large pipe size categories, for the purpose of extending the validity of the welder certificates. A.9

Certificate

The pipeline welder certificate shall be similar to that proposed in EN 287-1:1997 The certificate should clearly indicate by reference to this standard that the welders certification test has been performed under the conditions stated in Annex A. The original certificate is non-transferable and shall be directly in the possession of the welder or the contractor during execution of the work. The examiner present during test welding shall sign and stamp the original certificate.

Page 29 EN 12732:2000 Annex B (informative) Testing of the base material (lamination test)

Ultrasonic test equipment should be used for lamination tests; wall thickness measuring instruments should not be used for this purpose. Transmitter/receiver twin test probes or a single-crystal probe with detection zone greater than near field zone should be used. Ability to detect a flat-bottom hole of 2 mm diameter and a depth of 40 % of wall thickness through to the respective rear wall should be ensured.

Page 30 EN 12732:2000 Annex C (informative) Wall thickness compensation/Design examples

Figure C.1: Weld joint in the case of inadmissible high edge offset; transition piece with counterweld (dimensions in mm)

Figure C.2: Weld joint in the case of inadmissible high edge offset; machined off on root side

Figure C.3: Weld joint in the case of inadmissible high edge offset; machined off on root side and counterwelded (dimensions in mm)

Page 31 EN 12732:2000 Annex D (informative) Critical aspects for hot-tap welding or welding on gas-pressurised pipelines

D.1

General

This annex refers to 7.3 and describes the general variables which should be maintained for hottap welding or welding on gas-pressurized pipelines of category D (transmission pipelines). Parts of them are essential and should be stated in the welding procedure specification. This annex applies to: -

Split tees and repair sleeves

nominal diameter  DN 100

-

Threadolets and weldolets

nominal diameter  DN 100

-

Set-on branches

nominal diameter  DN 25

D.2

Definition

Temper bead method: A weld sequence whereby the heat-affected zone of the base material is softened as much as possible. D.3

Symbols

Hdm: Amount of diffusible hydrogen in 100 mg of weld metal. D.4

Recommendations

D.4. D.4.1 1 Equi Equipm pmen entt

Mechanical control of welding current. D.4. D.4.2 2 Supe Superv rvis isio ion n

Supervision should be performed by the pipeline operator or its nominee. D.4. D.4.3 3 Safe Safety ty prec precau auti tion ons s

Safety precautions should be taken and maintained in accordance with the pipeline operator's standard or the authority's regulations. Grouping of materials should comply with EN 288-3:1992, Table 3. D.4. D.4.4 4 Iden Identi tifi fica cati tion on

Prior to commencement of work, identification marks should be checked for compliance with the operator's standard. D.4. D.4.5 5 Fill Filler er mate materi rial als s

Filler materials should be in accordance with clause 5. The pipeline operator may specify a special brand. For the application, filler material requirements should be: - specified minimum yield strength  400 400 N/mm N/mm2; - ultimate tensile strength equal to or greater than 400 and up to and including 560 N/mm2 ; - A5  26 %; - KV  47 J/32 J;

Page 32 EN 12732:2000 - the verification test temperature in accordance with the pipeline operator's standard; - Hdm  3 ml from 3 sets. Single value up to and including 3,5 ml is allowed; - vacuum packaging should be specified; - type of 3.1.B certificate in accordance with EN 10204:1995. D.5

Weld pr preparation

Precautions should be taken to avoid arc strikes on the gas-pressurized pipeline in the case of longitudinal weldments: - by the use of backing strip; - by adequate spacing between fitting and pipe. Preparations should be in accordance with the appropriate EN standard. D.6

Welding procedure

Description: The contractor should specify the applicable welding procedure. The welding procedure should be approved by the pipeline operator. Approval: Approval should be given if the welding procedure meets the requirements of the pipeline operator's standard. Qualification: The procedure qualification should be performed in accordance with the pipeline operator's standard. (See also D.11). Validity: The validity of the welding procedure qualification may be changed at the discretion of the pipeline operator. D.7

Perf Perfo orman rmance ce of th the wel welde derr

Welders should prove their competence prior to commencement of work. A test weld should be executed and examined. (See also D.11). The welding method and specimen should be approved by the pipeline operator. The pipeline operator should qualify/approve the welders carrying out welding on gaspressurized pipelines. Validity: The validity of the welders performance qualification may be changed at the discretion of the pipeline operator. D.8

Precautions

To avoid cold cracking and burn-through, the following precautions are recommended: -

Normali Normalized zed steel steelss (used (used before before 1970 1970)) can be more more sensi sensitive tive to to cold crac cracking king.. The pipe pipeline line operator may take special measures by preheating and/or reducing gas flow.

-

A minimum minimum wall wall thickne thickness ss for for safe safe working working should should be be maintai maintained ned.. As a cons conseque equence nce,, a maximum allowable rod diameter and minimum run-out length should be specified.

Depres Depressur surizin izingg of the the pipel pipeline ine shou should ld be cons consider idered ed for for certai certainn minimu minimum m wall wall thicknesses. -

A minimum minimum flow flow should should be be maintai maintained ned for for certa certain in minim minimum um wall wall thick thickness nesses, es, at at the operator's discretion.

Page 33 EN 12732:2000 -

D.9

A minimum minimum dist distance ance betw between een a fittin fittingg and othe otherr weldme weldments nts shoul shouldd be specifi specified ed by the the pipeline operator. Execution

Seam preparation: Weld ends on the inside and outside of the fitting or sleeve should be ground smooth. Damaged surfaces: Minor surface damage can be repaired by grinding. Wall thickness reduction should be limited to 95 % of the minimum allowable wall thickness unless otherwise specified. A smooth transition to normal contour should be required with a maximum slope of 1:4. Also applicable are 6.1, 6.1.5 and 6.1.8. With respect to 6.1.8, the pipeline operator should be informed in the event of reportable defects. There should be equal spacing between the fitting and the pipe. The cap of the pipe seam weld should be removed by grinding, extending to 50 mm from each fillet weld of the fitting. Tack welding should be carried out by fully qualified welders. Preheating for tack welds should be specified. If applicable, the minimum required length of tack welds should be 50 mm. The maximum distance between tack welds should be 300 mm. Tack welding should be specified in the welding procedure specification. The pipeline operator should specify preheating parameters, if applicable. The welding sequence should be specified in the welding procedure specification. Unless otherwise specified, the maximum electrode diameter for wall thicknesses up to 7,0 mm should be 2,5 mm. Above 7,0 mm wall thickness, 3,25 mm electrodes can be used. Above 10,0 mm wall thickness, 4,0 mm electrodes may be used. Weaving is permitted up to twice the electrode diameter. Buttering may be used as a means of avoiding cold cracking. The pipeline operator can specify the temper bead method. To avoid excessive shrinkage, the specified weld sequence should be observed. Each fitting shall be clearly marked. D.10

Repairs

Each repair should require the pipeline operator's approval. Each repair should be specified and documented. Repaired welds should be 100 % inspected. D.11 D.11

Proced Procedure ure qualif qualifica icatio tion n rec record ord/we /welde lderr perfor performan mance ce qualif qualifica icatio tion n

The pipeline operator can specify special welding conditions for the welding procedure approval record . The procedure/performance test for welding on a gas-pressurized pipeline is optional. Testing should be in accordance with EN 288-3:1992. The pipeline operator may specify

Page 34 EN 12732:2000 Annex E (informative) Visual inspection of joints

E.1

General

This annex should be applied to all circumferential welds, branch and fillet welds. Visual inspection of joints should be performed in accordance with EN 970:1997. Requirements are based on acceptance criteria as laid down in Annex G. E.2

Recommandations

In addition to the requirements of 8.4 of EN 970:1997, it should be verified that the face angle between the parent metal and the weld metal is greater than 120  (see Figure E.1). In the case of circumferential welds, undercuts (with reference to Table G.1 or Table G.2,) should be permitted provided these have a smooth transition to the parent metal.

Figure E.1: Face angle between parent metal and weld metal

Page 35 EN 12732:2000 Annex F (informative) Manual ultrasonic testing of weld joints for wall thicknesses between approximately 6 mm and 10 mm

F.1

General

Testing details for wall thicknesses between approximately 6 mm and 10 mm are specified to ensure a precise distinction between geometric and defect echoes on the screen, where testing is carried out within the 50 mm test range measured within the shortened projection distance. Assessment of echo levels compared with circular disc reflectors as calibration values in this wall thickness range is possible only to a limited degree because the test takes place in the near field of the sound field. For this purpose, the following equipment is to apply: -

Miniatu Miniature re angle angledd test test heads heads with with 4 MHz MHz nomin nominal al frequ frequenc ency, y, a beam beam angle angle of of 70 and a fixed installed measuring staff.

-

Calibr Calibrati ation on block block with with groov groovee and edges edges in acco accorda rdance nce with with Figur Figuree F.1a. F.1a. The thic thicknes knesss shall not deviate from the nominal wall thickness of the pipeline to be measured by more than 10 %.

-

Calibr Calibrati ation on block block with with bored bored hole hole in accor accordan dance ce with with Figur Figuree F.2a. F.2a. The The block block shall shall be made made from flat steel complying with EN 10025:1994, e.g. S 355 N, and shall have a minimum cross-section of 36 mm x 20 mm and a minimum length of 140 mm.

Calibration of the ultrasonic tester and setting of the test sensitivity shall be carried out in accordance with F.2. F.2

Calibration

F.2. F.2.1 1

Adju Adjust stme ment nt of of spac spacin ing g

The calibration of the ultrasonic tester shall be carried out in the shortened projection distance, actually in the 50 mm test range. The use of calibration block no. 2 according to EN 27963:1992 is to be preferred. Using a calibration block as shown in Figure F.1a, a groove at spacing a1 (pos. 1) and a groove at spacing spacing a2 (pos. 2) or an edge edge at spacing a3 (pos. 3) should should each be scanned scanned and the correspondi corresponding ng echo base points set to the shortened projection spacings shown in Figure F.1b belonging to the spacings spacings a1 and a2 , or a3 , as applicable. applicable. By this the the echoes echoes should be be set to at at least 80 80 % of screen height. F.2.2 Sensitivit Sensitivity y adjustment adjustment when when using using the Distan Distance ce Gain Gain Size metho method d

The shape and location of the sloping curve (reference line) for a circular disc reflector of 1 mm diameter is shown in the Distance Gain Size diagram for the test head. The shape and location shall be specified by the test supervisory body, taking into account the respective acoustic attenuation and transferred to the screen using a waterproof colour pen. The test sensitivity will be determined on the basis of a cylindrical bored hole in the calibration block as shown in Figure F.2a. The echo signal of the cylindrical bored hole will be modulated to the level of the sloping curve using a dB amplification controller as shown in Figure F.2b. The amplification must then be increased by 8 dB. This amplification takes account of the difference in sensitivity between the signal from a circular disc reflector of 1 mm diameter and the signal from a cylindrical bored hole of 2 mm diameter with the same acoustic path.

Page 36 EN 12732:2000 NOTE: After the echo signal from the 2 mm cylindrical bored hole has been increased by 8 dB, the sloping curve for the wall thickness range from 10 mm to 12 mm will correspond to a circular disc reflector of 1 mm diameter (calibration standard). For the wall thickness range from approximately 6 mm to 10 mm, the sloping curve will correspond only approximately to a circular disc reflector of 1 mm diameter. To summarize, the following dB additions apply for setting the required test sensitivity: 2 mm cylindrical bored hole in the calibration block set to the level of the sloping curve x

dB

increase in amplification

+

transfer correction

+

dB

test sensitivity

=

dB

The additional amplification of 8 dB only applies when a miniature angled test head with a nominal angle of 70 and a nominal frequency of 4 MHz is used. Miniature angled test heads with nominal beam angles other than 70 (e.g. 80) or ominal frequencies other than 4 MHz (e.g. 2 MHz) are also usable. But in these cases the sloping curve, the sensitivity adjustment and the increase in amplification has to be specified by the test supervisory body.

Figu Figure re F.1 F.1a: a:

Cali Calibr brat atio ion n block block wit with h rect rectan angu gula larr groo groove ves s and and edge edge (All dimensions are in mm)

Figure F.1b:Screen display for adjustment

8

dB

Page 37 EN 12732:2000

Figure F.2a: Calibration block block with cylindrical cylindrical boring (All dimensions are in mm)

Figure F.2b:Screen display for adjustment of test sensitivity

Page 38 EN 12732:2000 Annex G (informative) Acceptance criteria recommendations for on-site production welds

G.1 G.1

Acce Accept ptan ance ce crit criter eria ia ac acco cord rdin ing g to EN 25 2581 817: 7:19 1992 92

Table G.1: Acceptance criteria according to EN 25817:1992 Quality requirement ca cattegor egory y in ac acco cord rdan ance ce with Table 1

Typ Type/ e/p posit ositio ion n of of the the weld weld join jointt

A+B

Assessment category to EN 25817:1992

Circumferential welds

Assessment category D except: Serial nos. 2,3,4,5,6 = C

Branches, nozzles, fillet welds

Serial no. 8 Long imperfections = C Short imperfections = D

Longitudinal seams

Serial no. 11 h  0,1 x T , but not more than 1,5 mm and a length of 50 mm

Unconcealed pipe spans; pipelines on bridges, pipeline sections crossing railways, major roads and motorways, navigable waterways or landing strips/runways C Circumferential welds

Assessment category C except: Serial nos. 12,13,14,15 = D

Branches, nozzles, fillet welds

Serial no. 8 Long imperfections = C Short imperfections = D

Longitudinal seams

Serial no. 11 h  0,1 x T , but not more than 1,5 mm and a length of 50 mm

Welds seams not included in the pressure test Unco nconcea ncealled pipe ipe spa spanns; pip pipeelin lines on bridges, pipeline sections crossing railways, major roads and motorways, navigable waterways or landing strips/runways

Same req requuire irements nts as as giv giveen in quality requirement category D

Continued

Page 39 EN 12732:2000 Table G.1 (continued): Acceptance criteria according to EN  25817:1992 Quality requirement category in ac acc cordanc ance with Table 1

Type Type/p /pos osit itio ion n of the the wel weld d joi joint nt

D

Circumferential welds

Assessment category to EN 25817:1992

Assessment category B except: Serial no. 8 Long imperfections = C Short imperfections = D Serial nos. 3,9,12 = C Serial no. 21 (see note 1) = C Serial nos. 24,25 not permitted

Branches, nozzles, fillet welds

Longitudinal seams, sweepolets

Serial no. 11 h  0,1 x T , but not more than 1,5 mm and a length of 50 mm For crater pipes (EN 26520:1991; ref.no. 2024) Same imperfections are acceptable as serial no. 5 = B Serial no. 16 Long imperfections = B Short imperfections = C Serial no. 17

weld joints not included in the pressure test

If pipelines/units are laid/installed in built-up areas

Imperfection with: l  10 mm b  4 mm h  4 mm acceptable Serial no. 18 (see note 2)

Unco Unconc ncea eale ledd pip pipee spa spans ns;; pip pipel elin ines es on bridges, pipeline sections crossing railways, major roads and motorways, navigable waterways or landing strips/runways

Seri Serial al no. no. 26 26 (se (seee not notee 3) 3)

NOTE 1: Internal concavity of any length is acceptable, provided the density of radiographic image of the internal concavity does not exceed the density of the thinnest adjacent base metal. If it does exceed this, the length is limited to 10 mm in any 300 mm of continuous weld or the total weld length, whichever is less. Serial no. 21 includes burn-through. NOTE NOTE 2: Permitt Permitted ed misalign misalignmen mentt of surfaces surfaces:: Wall thickness (T ) T  10  10 mm 10 mm < T  24  24 mm  > 24 mm T  >

Permissible external misalign ignment 0,3 x T  3,0 mm 0,125 x T 

Permissible internal misalign ignment 1 mm on entire circumference 2 mm over length DN 2,5 mm over length 1/3 DN

NOTE 3: Accumulated length of all imperfections in each 300 mm of continuous weld shall not exceed 50 mm. Concluded

Page 40 EN 12732:2000 G.2 G.2

Summ Summar ary yo off req requi uirem remen ents ts for for def defect ect acc accep epta tanc nce e lleve evels ls and and def defec ectt lim limit its s

The EPRG guidelines on the assessment of defects in transmission pipeline girth welds are based on literature reviews, an extensive laboratory test programme, published experimental data and accepted fitness for purpose methodologies. The guidelines are structured in three tiers and specify defect acceptance levels in Tier 1 (good workmanship) and defect limits in Tiers 2 and 3 (fitness-for-purpose). The application of current welding standards can lead to quite different defect limits. but the EPRG guidelines provide uniform acceptance levels and defect limits, with a comprehensive technical justification [1]. [1]

Gerhard Gerhard Knauf Knauf and and Phil Phil Hopkin Hopkins: s: The The EPRG EPRG guidel guidelines ines on the the assess assessment ment of defec defects ts in transmission pipeline girth welds, 3R international, 35 (1996), Journal number 10/11, October/November, 1996, pp. 620-624

EPRG EUROPEAN PIPELINE RESEARCH GROUP

a co-operation of European gas transmission and pipe manufacturing companies Address: Mannesmannröhren-Werke AG Mannesmann Forschungsinstitut Ehinger Straße 200, D-47259 Duisburg Postfach 25 11 60, D-47251 Duisburg MEMBERSHIP OF THE EUROPEAN PIPELINE RESEARCH GROUP (EPRG) BP International Limited, UK BG plc, UK British Steel plc, UK S.A. Distrigaz, Belgium Europipe GmbH, Germany Gaz de France, France ILVA/Lamiere e Tubi S.r.I., Italy Mannesmannröhren-Werke AG, Germany N.V. Nederlandse Gasunie, The Netherlands Preussag Stahl AG, Germany Rautaruukki Oy, Finland Ruhrgas AG/PLE GmbH, Germany Shell Internationale Petroleum Maatschappij B.V., The Netherlands S.N.A.M. S.p.A., Italy

Page 42 EN 12732:2000 Table G.2.2: Summary of defect acceptance levels (Tier 1) and defect limits (Tier 2 and Tier 3) T i er 1 Acceptance criteria

Type of defect

T i er 2 Limit criteria

T i er 3 Limit criteria

Exte Extern rnal al profi rofile le

Exce Excess ss weld weld meta metall shou should ld be unif unifor orm m and and not not more more than than 3 mm in heig eight. ht. It should merge smoothly with the parent metal and not extend beyond the original joint preparation by more than 3 mm each side. No area should have the weld face lower than the adjacent pipe surface.

Interna rnal pr profile

The ro root be bead or or an any c co oncavi avity s sh hould me merge rge s sm moothly iin nto th the a ad djace acent surface but at no point should the w eld be thinner than the pipe thickness.

Root concavity - Length

25 % of weld circumference

- Depth Undercut (cap) - Length

50 mm

7 x T 

- Total

50 mm in 300 mm or 15 % of circumference (if less)

7 x T  in  in any 300 mm

- Depth

1 mm or 0,1 x T  (i  (if less)

Undercut (root) - Length

Inadequate root penetration

Incomplete (lack of) cap fusion

7 x T 

 - Total

25 mm in 300 mm or 8 % of circumference (if less)

7 x T  in  in any 300 mm

- Depth

1 mm or 0,1 x T  (i  (if less)

- Length

25 mm

Figure G.1

Assumed to be < 3 mm 7 x T  Figure G.1

- Length

25 mm in 300 mm or 8 % of circumference (if less)

7 x T  in  in any 300 mm

25 mm

7 x T  Figure G.1

- Total

25 mm in 300 mm or 8 % of circumference (if less)

7 x T  in  in any 300 mm

- Length

25 mm

7 x T  Figure G.1

- Total Incomplete - Length fusion due to cold lap - Total Lack of - Length sidewall fusion - Total Lack of inter-run fusion

Figure G.1

Assumed to be < 3 mm

25 mm

- Total Incomplete (lack of) root fusion

1,5 mm or 0,1 x T  (if  (if less)

- Length

25 mm in 300 mm or 8 % of circumference (if less)

7 x T  in  in any 300 mm

50 mm

7 x T  Figure G.1

50 mm in 300 mm or 15 % of 7 x T  in  in any 300 mm circumference (if less) 50 mm

7 x T 

50 mm in 300 mm or 15 % of circumference (if less)

7 x T  in  in any 300 mm

50 mm

7 x T 

Figure G.1

Figure G.1 - Total

50 mm in 300 mm or 15 % of circumference (if less)

7 x T  in  in any 300 mm Continued

Page 43 EN 12732:2000 Table G.2.2 (continued): Summary of defect acceptance levels (Tier 1) and defect limits (Tier 2 and Tier 3) Tier 1 Acceptance criteria

Type of defect

Tier 2 Limit criteria

Cracks

Not allowed

Crater cracks

4 mm

Burn-through - Individual

6 mm

- Total Porosity, - Individual  < 10 mm T  < - Tot Total al

2 per 300 mm 3 mm or 0,25 x T  (if  (if less) When When proje roject cted ed radi radial ally ly throu hrough gh the the wel weld, d, not not to exceed a total area of 2 % of the projected weld area in the radiograph, calculated by multiplying the length of the weld affected by porosity, with a minimum of 150 mm, by the maximum width of the weld.

Porosity, - Individual T  10 mm - Total

Hollow bead, -Individual  < 10 mm T  < - Total

- Total

- Length - Total

Slag, T  10 mm

as for T  <  < 10 mm

5 % of projected area on radiograph

50 mm 50 mm in 300 mm or 15 % of circumference (if less)

as for T < 10 mm

5 % of projected area on radiograph

50 mm 50 mm in 300 mm or 15 % of circumference (if less)

as for T  <  < 10 mm

- Total

3 mm 12 mm in 300 mm and 4 in 300 mm

- Width Inclusions, T  10 mm

Figure G.1

3 mm or 0,5 x T  (if  (if less)

- Total as for T  <  < 10 mm

40 % of circumference

- Width Defect ac accumulation,   < 10 mm T  <

Figure G.1

40 % of circumference

- Width Inclusions,  < 10 mm T  <

Figure G.1

6 mm or 0,25 x T  (if  (if less)

- Length - Total

Figure G.1

6 mm or 0,25 x T  (if  (if less)

Hollow bead, - Length  > 10 mm T  >

Slag,  < 10 mm T  <

T i er 3 Limit criteria

Figure G.1 3 mm

100 mm in 300 mm or 15 % of pi pipe ci circumference (if less), excluding porosity

Figure G. G.1

(Root concavity is not included in accumulation calculations, unless it causes the weld thickness to be less than that of the pipe.) continued

Page 44 EN 12732:2000 Table G.2.2 (concluded): Summary of defect acceptance levels (Tier 1) and defect limits (Tier 2 and Tier 3)

Type of defect Defect interaction,  < 10 mm T  <

Defect ac accumulation,  > 10 mm T  >

T i er 1 Acceptance criteria

T i er 2 Limit criteria

Inherent in defect accumulation criteria

100 mm mm in in 30 300 mm mm or or 15 % of pipe circumference (if less), excluding porosity.

The la larger of of 7 x T  in  in any 300 mm or 100 mm in any 300 mm, excluding porosity. Slag is not included in the accumulation calculation, provided pipe material strength 450 N/mm2.

T i er 3 Limit criteria If a planar, slag or porosity defect is separated from a planar defect by a distance smaller than the length of the shorter of the two defects, then recategorize as a single planar defect of length equal to the two individual lengths + separation. Figure G.1 gives limits for interacting planar defects.

Figure G.1

Accumulation of planar defects shall be 15 % of circumference. Accumulation of planar and non-planar defects shall be 40 % of circumference. (Root concavity is not included in accumulation calculations, unless it causes the weld thickness to be le ss than that of the pipe.) Defect interaction, T  10 mm

Inherent in defect accumulation criteria.

If a planar, slag or po porosity defect is se separated from a planar defect by a distance smaller than the length of the shorter of the two defects, then recategorize as a single planar defect of length equal to the two individual lengths + separation. The recategorized plan planar ar defe defect ct shou should ld have have the the sa same me iden identi tity ty as the planar defect.

Figure G.1 gives limits for inte intera ract ctin ing g pla plana narr defe defect cts. s. Concluded

Page 45 EN 12732:2000

Figure G.1:Girth weld defects limits for Tier 3 (Wall thickness in mm)

G.3 G.3

Meth Method od and and a acce ccept ptan ance ce crit criteri eria a for for ultr ultras ason onic ic insp inspec ecti tion on asses assessm smen entt

G.3.1

Distance Gain Size method

The Distance Gain Size method should be used for the assessment of ultrasonic indications. The recording limits given in Table G.3.1 are applicable. Indications of defect reflections which exceed the results in Table G.3.2 are inadmissible. G.3. G.3.2 2

Com Compara parattive ive Ele Eleme men nt met metho hod d

When using the Comparative Element method, the test sensitivity after inclusion of the comparative line on a 3 mm cross hole shall be increased by 6 dB. Assessment shall be in accordance with Table G .3.2. G . 3. 3

General

Adjacent fault reflections at the same depth shall be separated by at least the length of the largest individual fault reflection; if not, they should be considered as a continous fault reflection length. The examination shall be performed in accordance with test rate 2 as given in EN 1714:1997. In critical cases or to improve the assessment, the test rate should be increased or other additional test procedures (e.g. radiographic examination) should be used. Weld joints on materials which have a tendency to hydrogen-induced cracking shall be checked after the post-welding diffusion of hydrogen, at the earliest 24 hours after the welding.

Page 46 EN 12732:2000 Table G.3.1: Recording of indications Calibration standards and fault reflection lengths using the Distance Gain Size method

Wall thickness (T ) mm

Calibration level circular disc reflector diameter mm

Sensitivity setting amplitude below calibration level by dB

Fault reflection lengths to be recorded above this length mm

6 < T   10 10

1 ,0

6

10

10 < T   15 15

1, 0

6

10

15 < T   20 20

1, 5

6

10

20 < T   40 40

2, 0

6

10

 > 40 T  >

3, 0

12

10

Table G.3.2: Assessment of indications using the Distance Gain Size method Maximum allowable numbers and sizes of reflectors

Wall thickness T  *  * in mm

 6  T  10  10

Number of indications per m of seam

Maximum allowable lengths of reflectors per echo** mm

Echo level above calibration level dB

5 an d 2

10 20



10 < T  20  20

10 an d 3 an d 1

10 20 10

6 6 12***

20 < T  40  40

10 an d 4 an d 1

10 25 10

 6  6  12***

10 an d 4 an d 1

10 30 10

 6  6  12***



40 < T  60  60

 6  6



 

 

NOTES: *

If wall wall thic thickkness nesses es diff differ er,, the the lowe lowerr wal walll thi thiccknes knesss sha shallll be dec decisiv isive. e.

**

For For con confifirm rmed ed vol volum umee defe defect ctss (no (nott in the the vic vicin initityy of of the the sur surfa face ce), ), faul faultt leng length thss exceeding the calibration levels by up to 6 dB can be allowed up to 1,5 times the allowable length. Confirmation may take the form of a radiographic examination.

*** ***

The The acc accept eptabi abilit lityy of of sing single, le, large large defec defects ts shall shall be conf confirm irmed ed on the basis basis of rand random om samples, e.g. by means of radiographic examination.

Page 47 EN 12732:2000 Annex H (informative) Recommendations for brazing and aluminothermic welding of anodic bonding leads

H.1 Joinin Joining g techni technique ques s

Full details of the joining technique and associated equipment should be submitted to the pipeline operator for approval prior to use and should conform to the manufacturer‘s reco mmendations.

H.2 Procedu Procedure re qualifica qualificatio tion n

Prior to starting, the contractor should submit a preliminary welding procedure procedure specification to the pipeline operator for approval. The procedure should be qualified by making three consecutive test joints in the presence of the pipeline operator on material to be used in production. The test material should be selected by the pipeline operator to represent the upper quartile of the carbon equivalent range. The electrical resistance of each joint should be measured and should not exceed 0,1 strength of the joint should be tested by means of a sharp blow from a 1 kg hammer.

.

The mechanical

All three test joints should be sectioned and prepared for metallographic examination. examination. The following tests should be performed on the sections. a) Copper penetration measurement The depth of copper penetration below the surface of the pipe material should be measured metallographically. The fusion line of the weld or braze should not be more than 1mm below the pipe surface. Intergranular copper penetration of the pipe material should not exceed 0,5 mm beyond the fusion line when a micro-section is examined at a magnification not exceeding x 50. b) Hardness su survey Each section should be tested using a 10 kg load. A traverse should be made across the weld zone as shown in Figure Figure H.1 and should consist of at least six impressions; two in the heat-affected zone each side of the weld/braze and one in the parent metal each side of the weld/braze. The hardness values should not exceed 325 exceed 325 HV10, or they should be as specified by the pipeline operator.

Parent metal surface

Weld/braze metal

1

2

4 3

6

5

Weld heat-affected zone (visible after etching) NOTE:Hardness impressions 2, 3, 4 and 5 should be entirely within within the heat-affected zone and located as close as possible to the fusion boundary. All dimensions are in millimetres

Figure H.1:Recommended H.1:Recommended locations for hardness traverses and impressions for brazing and aluminothermic welding

H.3

Operation qualific ation

Prior to carrying out production work, each operator should complete three test joints which should pass the tests for electrical conductivity conductivity and mechanical strength (hammer test) required in H.2. All welding and tests should be witnessed by the pipeline operator.

Page 48 EN 12732:2000 H.4

Production joints

The attachments should be located at least 150 mm from any seam or circumferential weld. The weld area should be clean, dry and free from oil, grease, mill scale or other foreign matter. Preheating should be applied as specified in the approved procedure. All attachments should be tested for mechanical resistance strength (hammer test), followed by an electrical continuity test, both as recommended in H.2. Should any attachment prove to be defective, it should be carefully removed, ensuring that the parent material thickness is not reduced below the specified tolerances. Rejoining should be carried out at a new location on the pipe.

Page 49 EN 12732:2000 ANNEX I (informative) Bibliography

EN 288-1 288-1:1 :1992 992

Spec Specififica icatio tionn and appro approva vall of weldi welding ng proc procedu edure ress for for metall metallic ic mate materia rials ls Part 1: General rules for fusion welding

EN 444: 444:19 1994 94

NonNon-de dest stru ruct ctiv ivee tes testiting ng - Gen Gener eral al prin princi cipl ples es for for the the radi radiog ogra raph phic ic exam examin inat atio ionn of of metallic materials using X-rays and gamma-rays

EN 462-1 462-1:1 :199 9944

NonNon-de dest stru ruct ctiv ivee tes testin tingg - Imag Imagee qual quality ity of radio radiogr graph aphss - Part Part 1: Image Image quali quality ty indicators (wire type) - Determination of image quality values

EN 462-2 462-2:1 :1994 994

NonNon-de dest stru ruct ctiv ivee tes testin tingg - Image Image quali quality ty of radio radiogr graph aphss - Part Part 2: Image Image quali quality ty indicators (step/hole type) - Determination of image quality value

EN 1712 1712:1 :199 9955

NonNon-de dest stru ruct ctiv ivee exam examin inat atio ionn of wel welds ds - Acce Accept ptan ance ce cri crite teri riaa for for ultr ultras ason onic ic examination of welded joints

EN 10025: 10025:19 1994 94

Hot rolle rolledd prod produc ucts ts of non non-a -allo lloyy str struc uctur tural al ste steels els;; tec techni hnica call deliv deliver eryy cond conditi ition onss (includes amendment A1: 1993)

EN ISO ISO 6947: 6947:1997 1997

Welds Welds - Workin Workingg positio positions, ns, defin definitio itions ns of of angles angles of slope slope and and rotati rotation on

UNI Ente Nazionale Italiano di Unificazione

Via Battistotti Sassi, 11B 20133 Milano, Italia

La pubblicazione della presente norma avviene con la partecipazione volontaria dei Soci, dell’Industria e dei Ministeri. Riproduzione vietata - Legge 22 aprile 1941 Nº 633 e successivi aggiornamenti.