1.1 This test method covers the testing of large single- and double-walled tanks, pressure and vacuum vessels, laminated, lined- or double-walled parts, complex piping systems, flexible containers (such as aircraft fuel tanks), glass-to-metal seals in hybrid packages, and systems that inherently contain or will contain ammonia (such as large tonnage refrigeration systems and fertilizer storage systems).1.2 This method can be used on piping, valves and containers with welded, fitted, or