scope:

This document contains requirements for the production and testing of weld joints for the installation and modification, including in-service welding, of onshore steel pipelines and pipework used in gas infrastructure. This includes all pressure ranges and processed, non-toxic and non-corrosive natural gas according to EN ISO 13686 and non-conventional gases such as (injected) biomethane and hydrogen, where:

- the pipeline elements are made of unalloyed or low-alloyed carbon steel;

- the pipeline is not located within commercial or industrial premises as integral part of the industrial process on those premises except for any pipelines and facilities delivering gas to such premises;

- the pipework is not located within household installations according to EN 1775;

- the design temperature of the system is between −40 °C up to and including 120 °C.

For injected biomethane or hydrogen a detailed technical evaluation of the functional requirements is required, ensuring there are no other constituents or properties of the gases that can affect the integrity of the pipeline.

This document is not applicable to welds produced prior to the publication of this document.

Table 1 assigns the application areas to quality requirement categories as a function of the working pressure and pipe materials used.

When using this standard the following is defined by the pipeline operator, the applicable paragraph is given in brackets;

a) Applicable quality requirement category. (scope)

b) Applicable quality requirements as defined in Table 2. (4.1)

c) Are there specific requirements on VT testing, personnel, and/or qualification. (4.1)

d) Applicable welding qualification standards. (4.3)

e) Are all weld metal tensile tests required. (4.3)

f) When process 311 is used, applicable requirements for welder qualification. (4.4)

g) For category B and C, are batch certificates required for welding consumables, when required the pipeline operator has to define the contents of the certificate. (Clause 5)

h) For filler materials not in accordance with listed European standards, is batch qualification with WPQR allowed. (Clause 5)

i) If overmatching weld material is required. (Clause 5)

j) If hot deformation for misalignment compensation is allowed for materials of R_t 0,5 ≤ 360 MPa. (6.2.2)

k) Is the weld always to be covered after completion of welding. (6.6)

l) For category D, requirements for repair welding procedures. (6.7)

m) Extent of NDT techniques. (8.2)

n) Alternative acceptance criteria when applicable. (8.3)

o) When alternative criteria in accordance with Annex G are used, if alternative weld overmatching criteria are applicable.

Additional requirements may be specified when, for example:

- the strain on pipelines and systems,

- the materials,

- the line routing,

- the design or the welding technique

are considered critical.

This document specifies common basic principles for gas infrastructure. Users of this document should be aware that there can exist more detailed national standards and/or codes of practice in the CEN member countries.

This document 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 document, the national legislation/regulation takes precedence as illustrated in CEN/TR 13737 (all parts).

NOTE CEN/TR 13737 (all parts) contains:

- clarification of relevant legislation/regulations applicable in a country;

- if appropriate, more restrictive national requirements;

- national contact point for the latest information.