ISO 13920:2023

This document specifies general tolerances for linear and angular dimensions and for shape and position of welded structures in four tolerance classes, based on customary workshop accuracy. The main criterion for selection of a particular tolerance class is based on the functional requirements which are to be met.
The applicable tolerances are always those which are stated in the drawing. Instead of specifying individual tolerances the tolerance classes according to this document can be used.
General tolerances for linear and angular dimensions and for shape and position as specified in this document apply for weldments, welding assemblies, welded structures, etc.
Special provisions can be necessary for complex structures.
The specifications given in this document are based on the independency principle of ISO 8015, according to which the dimensional and geometrical tolerances apply independently of each other.
Manufacturing documentation in which linear and angular dimensions or indications for shape and position are presented without individually indicated tolerances shall be deemed incomplete if there is no, or inadequate, reference to general tolerances. This does not apply to temporary dimensions.