Very often the decisions on how a weld should be made, filler metal and welding parameter selection are left to the welder. While this may be acceptable in those situations where the weld quality is only incidental to the integrity of the fabrication it is not acceptable where the weld is crucial to the performance of the component. The need for approved welders to work to approved welding procedures is also often a requirement of either the application standard to which the fabrication is designed and constructed or a contract specification requirement. Aside from these specification requirements it may be necessary for the fabricator to be able to demonstrate to clients, to regulatory authorities or, should a failure leading to loss or damage occur, to a court of law that the welds have been made to an acceptable quality. To specify how both the welds and the welders may be shown to be acceptable there are a number of standards available to the engineer. The requirements of some of these standards are covered in this chapter.
It cannot be emphasised too strongly that the detail below is only a summary of the specification requirements and must be treated with caution. Although best efforts have been made to ensure that the abstracts are accurate, they are only abstracts and accurate at the time of writing. Where compliance is a standard or contract requirement the latest edition of the approval standards must be consulted.