NFPA 54

Covers — fuel-gas (natural gas/LP-gas) piping downstream of the meter: pipe sizing to appliance demand, approved materials and joining, pressure/leak testing, and appliance connection and venting within/around buildings.

Does NOT cover (exclusions) — gas transmission/distribution up to the meter → ASME B31.8; LNG facilities → NFPA 59A; medical gases → NFPA 99.

NFPA 54 governs building fuel-gas piping downstream of the meter; upstream distribution is B31.8.

NFPA 54 sets requirements for fuel-gas piping:

• Sizing — pipe sizing to deliver the appliances' gas demand at required pressure.
• Materials & Joining — approved pipe/tube materials and joining methods.
• Testing — pressure and leak testing before use.
• Appliance Connection & Venting — connection, shutoff, and combustion-venting provisions.

NFPA 54, the National Fuel Gas Code (ANSI Z223.1), governs fuel-gas piping — natural gas and LP-gas — downstream of the utility meter, within and around buildings. It covers pipe sizing to the appliance demand, approved materials and joining, pressure/leak testing, and appliance connection and combustion venting.

It defines the handoff from the gas-distribution code (ASME B31.8, which ends at the meter) to building fuel-gas piping, and is a life-safety code enforced by the authority having jurisdiction. LNG facilities and medical gases fall under NFPA 59A and NFPA 99 respectively.

Engineering Note: Size the fuel-gas piping for the simultaneous appliance demand at the delivered pressure, and always pressure/leak-test before use — an undersized or leaking fuel-gas line is both an appliance-performance and a life-safety problem.