ISO 13259:2020 specifies a test method for determining the leaktightness of elastomeric sealing ring type joints for buried thermoplastics non-pressure piping systems.

Unless otherwise specified in the referring standard, the tests are carried out at the following basic test pressures:

— p₁: internal negative air pressure (partial vacuum);

— p₂: a low internal hydrostatic pressure;

— p₃: a higher internal hydrostatic pressure.

It also describes the following four test conditions under which the tests are performed:

a) Condition A: without any additional diametric or angular deflection;

b) Condition B: with diametric deflection;

c) Condition C: with angular deflection;

d) Condition D: with simultaneous angular and diametric deflection.

The applicable selection of the test pressure(s) and the test condition(s) is/are specified in the referring standard.