This European Standard specifies techniques for the manual ultrasonic testing of fusion welded joints in metallic materials equal to and above 8 mm thick which exhibit low ultrasonic attenuation (especially that due to scatter) at object temperatures from 0°C to 60°C. It is primarily intended for use on full penetration welded joints where both the welded and parent material are ferritic. Where material dependent ultrasonic values are specified in this standard they are based on steels having an ultrasonic sound velocity of 5920 ± 50 m/s for longitudinal waves, and 3255 ± 30 m/s for transverse waves. The standard specifies four testing levels, each corresponding to a different probability of detection of imperfections. Guidance on the selection of testing levels A, B and C is given in annex A. The requirements of testing level D, which is intended for special applications, shall be in accordance with the general requirements of this standard and may only be used when defined by specification. This includes tests of metals other than ferritic steel, tests on partial penetration welds, tests with automated equipment, tests at object temperatures outside the range. This standard may be used for the assessment of indications, for acceptance purposes, by either of the following techniques: a) Evaluation based primarily on length and echo amplitude of the signal indication; b) Evaluation based on characterization and sizing of the indication by probe movement techniques. The techniques used shall be specified.