The Chlorine Institute recognizes three (3) piping pressure testing techniques

All new or modified chlorine piping systems must undergo pressure testing to verify the integrity of the piping (see section 11.4 for leak testing). ASME B31.3 (13.2.8 ), Process Piping testing requirements, should be applied as a minimum standard. There are three (3) types of acceptable testing methods:

1. hydrostatic testing,
2. pneumatic testing, and
3. the alternate test method. 

ASME Code or your company procedures should be followed for any testing that may be required for repairs and additions made after the piping system is initially tested.