After successful completion of the initial pressure tests under Section 1318.8.7, Category 3 gas-powered device distribution piping shall be subjected to a standing pressure test, which includes the following:
- Tests shall be conducted after the installation of outlet valves and other distribution system components (e.g. pressure indicators and line pressure relief valves).
- The source valve shall be closed unless the source gas is being used for the test.
- The piping systems shall be subjected to a 24 hour standing pressure testing using oil-free, dry nitrogen NF or the system gas.
- Test pressures shall be 20 percent above the normal system operating line pressure.
- At the conclusion of the tests, there shall be no change in the test pressure greater than a gauge pressure of 5 psi (34 kPa).
- Leaks, if any, shall be located, repaired (if permitted), or replaced (if required), and retested. [NFPA 99:5.3.12.2.9]