The old question… Do we need to pressure-test and leak-test our piping after we breach the pressure boundary? My response is always YES; however, the International Gas Code says something very different. Can we apply this approach to ASME B31.3 piping?
406.1.2 Repairs and additions.
In the event repairs or additions are made after the pressure test, the affected piping shall be tested.
Minor repairs and additions are not required to be pressure tested provided that the work is inspected and connections are tested with a noncorrosive leak-detecting fluid or other approved leak-detecting methods.
406.1.3 New branches.
Where new branches are installed to new appliances, only the newly installed branches shall be required to be pressure tested. Connections between the
new piping and the existing piping shall be tested with a noncorrosive leak-detecting fluid or other approved leakdetecting methods.
406.1.4 Section testing.
A piping system shall be permitted to be tested as a complete unit or in sections. A valve in a line shall not be used as a bulkhead between gas in one section of the piping system and test medium in an adjacent section, except where a double block and bleed valve system is installed. A valve shall not be subjected to the test pressure unless it can be determined that the valve, including the valve-closing mechanism, is designed to safely withstand the test pressure.