Specifies the procedures to be used for the ultrasonic detection of predominantly longitudinal imperfections in: (i) Seamless and welded steel tubes and (ii) Seamless and welded titanium tubes, together with reference notches and acceptance criteria. Covers tubes of outside diameters 12 mm up to, but not including, 160 mm. Where there is a supplementary requirement stated in the Product Specification for the ultrasonic testing of tubes for the detection of predominantly transverse imperfections, the requirements of Appendix A shall be applied. Where tubes are to be externally finned or internally ribbed, the requirements of this part of the Standard shall be applied prior to these processes being carried out. Does not apply to integral longitudinally finned tube.