When is a WPS considered valid?

A Welding Procedure Specification (WPS) is considered valid when it has been tested and approved because this ensures that the welding procedure meets the necessary standards for safety and quality. The approval process typically involves demonstrating that the welding parameters, techniques, and materials will produce sound welds that fulfill the requirements set forth in the applicable codes, such as AWS D1.1. Testing might include qualifications through procedure qualification records (PQR) that document the actual welding performed and the resulting mechanical properties of the welds.

This validity is crucial because it gives assurance that the specified welding methods will produce reliable and structurally sound welds under the conditions outlined in the WPS. A WPS that hasn't been tested or approved would lack this verification, potentially leading to issues with the integrity of the welds in real-world applications.

Other options suggest scenarios that do not provide a basis of confidence in the WPS, such as having no documentation or review, which is vital to ensure compliance with welding standards. Additionally, the timeframe for usage does not inherently determine the validity of the WPS itself; rather, it pertains to the ongoing relevance and applicability of the approved procedure in a changing work environment.