This International Standard specifies the approach to be followed when developing procedures for the ultrasonic testing of the following welds: welds in stainless steels; welds in nickel-based alloys; welds in duplex steels; dissimilar metal welds; austenitic welds. The purposes of the testing can be very different, e.g.: for the assessment of quality level (manufacturing); for the detection of specific discontinuities indications induced in service. Acceptance levels are not included in this International Standard, but can be applied in accordance with the scope of the testing (see Clause 5). The requirements of this International Standard are applicable to both manual and mechanized testing.