Prior to installing an 8' diameter double wall tank, the inner tank must be pressurized to a maximum of _____ psig for a period of ____ hour(s).

• A. 3, 1
• B. 3, 24
• C. 5, 1
• D. 5, 24

Answer: (C)

Testing the inner tank’s tightness before installation is done by applying a controlled pressurization to reveal leaks. The inner tank must be pressurized to a maximum of 5 psig and held for 1 hour. This setting provides enough pressure to stress the tank enough to expose leaks while staying within safe limits to prevent damage to the tank, fittings, or seals. A lower pressure like 3 psig might not reveal small leaks, and a longer duration such as 24 hours isn’t needed for this pre-install test and would unnecessarily slow the process. The 5 psig, 1-hour test strikes the right balance between detectability, safety, and efficiency for this procedure.