This publication applies to the inspection and evaluation of DOT/TC 3-Series and ISO 11120 tubes 12 ft (3.7 m) or longer with an outside diameter greater than or equal to 18 in (457 mm) that are supported by the neck mounting surface. It provides methods to assess the integrity of tube necks including, but not limited to, mounting threads, pin or set screw marks, and other damage to identify rejectable tubes. Tubes with a smaller diameter are outside the scope of this publication.

This publication also applies if a saddle unit is being reconfigured into a unit supported by mounting threads.