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What is dual certification or parallel certification for procedure qualification? Are there any restrictions on dual certification?


Frequently Asked Questions

A single set of test specimens has been used in the past to certify weldments against two internationally recognised testing requirements; this is referred to as 'dual certification'. It has been the practice for some time for testhouses to issue test reports to accompany an ASME IX and a BS EN/BS EN ISO welding procedure qualification test certificate, but to base these reports on tests carried out to one or other of these two welding standards. In August 2006,UKAS issued a policy statement to all UKAS Accredited laboratories on the subject of dual certification when testing and issuing test reports for welding procedure qualification tests. This policy is effective from 30 September 2006.

The UKAS policy statement states that UKAS accredited laboratories are obliged to work to BS EN ISO/IEC 17025 and that this standard requires laboratories to 'report accurately, clearly, unambiguously and objectively'. The report goes on to detail the differences in test piece types, test piece locations and test methods between ASME IX and the European welding procedure qualification standards such as BS EN 15614. The clear message from UKAS is that the practice of dual certification, based on a single set of tests to one or other of these standards, must not be used by UKAS accredited laboratories because this practice is not compatible with the requirements of BS EN ISO/IEC 17025. However, providing that the test instructions allow, a single specimen can be used for dual certification to meet the requirements of both standards. Combining the two requirements may enhance some tests, such as visual examination and the hardness survey, providing the combined approach meets both requirements.

Whilst it could be argued that the differences in some details of the test pieces and/or test methods may give very little difference in test results, the principle that underpins the UKAS policy statement is sound.

An end-user, contractor, fabricator or test house could find that absolute compliance with a contract specification for testing and certification for a welding procedure qualification could become a major issue in the event of a situation that leads to litigation.

'Parallel' certification, requiring two sets of tests from the same welded test specimen, would have to be produced by UKAS laboratories to comply with the UKAS policy directive for certification to ASME and the European welding procedure qualification test requirements, or indeed other combinations of American and European welding standards.

Thus the only way that UKAS accredited laboratories should operate when requested to dual certify a weld procedure test is to produce a set of test pieces in accordance with each standard and carry out tests in accordance with the procedures referenced by each standard. Thus 'dual certification' may now have to be referred to as 'parallel certification'. Parallel certification will have a significant cost implication because the welding engineer will need to supply longer test welds to ensure there is sufficient test material for all the tests and the test house costs will increase in accordance with the additional tests.

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