The leak test for large gas piping installations shall not exceed what maximum test pressure in psig?

• A. 50 psig
• B. 100 psig
• C. 150 psig
• D. 200 psig

Answer: (B)

Leak testing gas piping is done at a higher pressure than normal operation so leaks will show up, but the pressure must stay within what the system components and test equipment can safely handle. For large gas piping installations, NFPA 54 sets a cap of 100 psig for the test pressure. This limit provides an effective leak check while avoiding overstressing pipes, joints, and appliances or exceeding ratings of typical equipment used in natural gas systems. Pressures like 150 or 200 psig would risk damage, and 50 psig might not reliably reveal leaks in larger installations. If the system is designed for higher operating pressures, the code specifies the appropriate higher-pressure procedures, but for standard large installations, 100 psig is the maximum.