ISO 7233:2021

This document specifies three methods for determining the resistance to vacuum of hoses and hose assemblies manufactured from plastic or rubber. Applicable dimensions of hoses for each method are as follows:
-  method A for hoses of nominal size up to and including 80;
-  method B for hoses of nominal size greater than 80;
-  method C for hoses of all dimensions.
If not otherwise specified in the product standard, method C can be used as an alternative to methods A and B.
Methods A and B can also be used to check the adhesion of the lining to the reinforcement (delamination) in a length of hard-wall hose or hose assembly.