This International Standard gives guidelines for the choice of non-destructive testing (NDT) methods for welds and evaluation of the results for quality control purposes, based on quality requirements, material, weld thickness, welding processs and extent of testing. This international standard also specifies general rules and standards to be applied to the different types of testing, for either the methodology or the acceptance level for metallic materials. Acceptance levels cannot be a direct interpretation of the quality levels defined in ISO 5817 or ISO 10042. They are linked to the overall quality of the produced batch of welds. Requirements for acceptance levels for non-destructive testing comply with quality levels stated in EN ISO 5817 or EN ISO 10042 (moderate, indermediate, stringent), only on a general basis and not in detail for each indication. Annex A gives correlation between quality, NDT and acceptance level standards.