Before permitting the use of gas at any location, the piping shall be tested for tightness and leaks in accordance with Part 4 of the American National Standard “National Fuel Gas Code”, ANSI Z223.1 (1988), which is incorporated by reference under COMAR 20.55.02.02. Pressure Test. Before any system of gas piping is finally put in service, it shall be tested for tightness and certified by the proper inspection authority that the test has been made. Leakage Test. Before turning gas into any piping, it shall be tested for leaks.