(1) After gas appliances have been connected, the gas-piping system must be subjected to a pressure test with the burner valves closed. The test consists of air at not less than ten inches nor more than fourteen inches pressure of water column (six to eight ounces). The system must hold this pressure for a period of not less than ten minutes with no leakage. Before beginning the test, the temperature of the gas-piping system and the test air must be equalized, and this shall be maintained throughout the test.

(2) Appliance shut-off valves ahead of gas cooking appliances may be closed for the performance of this test. When the test is satisfactorily performed, these valves must be opened and, while the system is under pressure, the appliance connectors must be tested with an approved leak detector or approved bubble solution.