Ignite Your Future: Ace the 2026 NFPA 54 National Fuel Gas Code Practice Exam!

The test duration is tied to the amount of pipe being tested because the volume under test—and thus the time needed to reliably spot a leak—grows with length. Using a standard unit of 100 feet of piping provides a consistent way to scale the leak test: longer runs require proportionally longer testing time to allow any pressure drop from a leak to become evident. This standardization helps ensure leaks are detected regardless of system size, without over- or under-testing shorter or longer installations.