Gas piping test pressure is commonly specified in which unit?

Gas piping test pressure is commonly specified in which unit?

• A. PSI
• B. PSIG
• C. Bar
• D. kPa

Answer: (B)

Gas piping test pressure is given in PSIG because the test readings need to reflect pressure above atmospheric pressure. Gauges used for these tests measure how much pressure exists above ambient air, so expressing the requirement in psig keeps it simple and directly comparable to the gauge readings you’ll use during the test. Using absolute pressure (PSIA) would require accounting for atmospheric pressure in every reading, which complicates interpretation. Bar and kPa are metric units and are not the standard convention in this U.S. NFPA 54 testing context. So PSIG is the practical, conventional choice.

Gas piping test pressure is given in PSIG because the test readings need to reflect pressure above atmospheric pressure. Gauges used for these tests measure how much pressure exists above ambient air, so expressing the requirement in psig keeps it simple and directly comparable to the gauge readings you’ll use during the test. Using absolute pressure (PSIA) would require accounting for atmospheric pressure in every reading, which complicates interpretation. Bar and kPa are metric units and are not the standard convention in this U.S. NFPA 54 testing context. So PSIG is the practical, conventional choice.