Use of alternative Standards

A recent addition to AS885.info answered a question about weld procedure qualification using other Standards. This provides a nice opportunity to address a broader issue that is perhaps under-appreciated.

A general principle is that it is not appropriate to pick and choose from a mix of different Standards covering the same subject. Rather a single Standard must be chosen and used in its entirety. Certainly in the pipeline industry there is a range of Standards available for both pipeline systems as a whole (AS 2885, ASME B31 series, etc) and piping fabrication (AS 2885, AS 4041, ASME B31 series, ASME BPVC, etc).

In practice in Australia the choice of Standard is not usually a problem because AS 2885 is mandated in most States. Nevertheless AS 2885 does permit use of other Standards in some situations, particularly piping fabrication. The overall principle for use of other Standards is governed by Clause 1.6.3 of Part 0, which expresses the intent that the other Standard be used in full (you are familiar with Part 0, aren’t you?).

The reason for using a single Standard in its entirety is is to avoid the possibility of inconsistencies or omissions which might occur if requirements are taken from different Standards.

A lightly edited version of the AS2885.info post is copied below. Even if the specific details are not relevant to you it nicely illustrates the principle of not picking and choosing between Standards.



Question:

Versions of AS 2885.2 prior to 2020 allowed weld procedure qualification of AS 2885.1 pipeline assemblies to alternative standards (such as ASME IX). Is this still allowed? If not, what is the reason?

Answer:

The qualification requirements for pipeline assemblies were tightened in the 2020 version of AS 2885.2. If the pipeline assembly is designed to AS 2885.1 then it must be welded using a procedure qualified to AS 2885.2. If it is designed to an alternative standard such as AS 4041 or ASME 31.3, then it can be welded using a procedure qualified to AS 3992 or ASME IX respectively, as long as the fracture testing requirements are met, material yield strength < 450 MPa and the WPS is approved by a Welding Engineer. The detailed requirements can be found in section 6.4.3.

When standards are written in parts, each of the parts needs to be used in conjunction with the other parts. This is the case with the AS 2885 series. In particular, Part 2 is written specifically considering the requirements of Part 1. ASME B31.3 has different design approaches, material requirements, NDT requirements etc. compared to AS 2885. Similarly ASME IX is written to meet the requirements of various standards including ASME B31.3 but does not meet all of the requirements of AS 2885.1. Therefore it is not appropriate to mix these standards

Previous to the 2020 version of AS 2885.2, qualification to alternative standards was allowed, such as ASME IX. This created many issues such as fracture control, NDT acceptance criteria, NDT methods, qualification ranges etc. and with improper application could result in welded joints that are not fit for purpose.

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