EN 1277 test pressures for determining the leak tightness of elastomeric sealing ring type joints buried thermoplastics piping. This European standard specifies three basic test pressures for determining the leaktightness of elastomeric sealing ring type joints for buried thermoplastics non-pressure piping systems.

EN 1277 Leakage tightness test machine. 

Unless otherwise specified in the referring standard, the methods pressures used are the following:

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

-   p2:  a low internal hydrostatic pressure;

-   p3:  a higher internal hydrostatic pressure.

It also describes four test conditions under which the test can be executed, as follows:

A:   without any additional diametric or angular deflection;

B:   with diametric deflection;

C:   with angular deflection;

D:   with simultaneous angular and diametric deflection.

These conditions can be applied individually or in combination. The applicable selection of the method(s) and the condition(s) should be specified in the referring standard.