NFPA 54 — the National Fuel Gas Code — and NFPA 58 — the Liquefied Petroleum Gas Code — govern the two primary fuel sources for emergency generators. Natural gas-fueled generators fall under NFPA 54 for their fuel piping, regulators, and connections. LP-gas (propane) fueled generators fall under NFPA 58 for tank installation, setbacks, piping, and safety devices. A generator that runs perfectly but has a non-compliant fuel supply is a non-compliant system.
We audit fuel gas systems as part of our emergency power compliance review, identifying piping, storage, and documentation gaps that affect both NFPA 54/58 compliance and the overall NFPA 110 EPSS program.
What NFPA 54 & 58 Cover
NFPA 54 covers the installation of fuel gas piping systems, appliance venting, and combustion air requirements for natural gas and similar gaseous fuels. It applies from the point of delivery (the gas meter) to the connection at each appliance — including emergency generators. Key requirements include pipe sizing for adequate flow, pressure testing of all joints, proper support and protection of exposed piping, and clearance from ignition sources.
NFPA 58 covers LP-gas (propane) from the storage container through the piping to the appliance. It defines tank location setbacks from buildings, property lines, and other tanks. It covers relief valve sizing, tank corrosion protection, fill procedures, and the specific requirements for stationary installations. For facilities with propane-fueled generators, NFPA 58 is the controlling standard for the entire fuel supply side of the emergency power system.
Fuel Supply & Generator Integration
For natural gas generators, NFPA 54 requires that the gas piping be sized to deliver adequate volume at the required pressure during full-load operation. This sizing must account for all other gas appliances on the same supply. An undersized gas line can cause a generator to trip on low fuel pressure under load — exactly the condition that matters during an actual power outage. Pressure testing of all new piping and connections is required, and test documentation must be retained.
For LP-gas generators, NFPA 58 requires specific setback distances between the storage tank and the building, the generator, property lines, and sources of ignition. Tank installations must include proper overfill protection, emergency shutoff valves, and cathodic protection for underground tanks. Many facilities install LP tanks and generators without verifying that the setback distances comply — a violation that is immediately visible during an AHJ inspection.
The Generator That Couldn't Hold Load
A skilled nursing facility's natural gas generator started and ran during monthly testing but had never been tested under actual building load. During a power outage, the generator started on time but began surging and eventually tripped on low fuel pressure after 22 minutes. The gas supply line — originally sized for the building's heating load only — could not deliver adequate volume when the generator added its full-load demand.
Result: The facility lost emergency power for over four hours while the utility company restored service. CMS cited the facility for EPSS failure. The root cause was a gas piping system that violated NFPA 54 sizing requirements — the line was never re-sized when the generator was added. The fix required upsizing 120 feet of gas piping, a new regulator, and a pressure test — $47,000 total.
Generator fuel supply is not separate from generator compliance — it is part of it. NFPA 54 requires that gas piping be sized for the total connected load, including the generator. We verify fuel system sizing, pressure capacity, and documentation as part of every EPSS compliance audit.
How We Help
We audit your facility against the specific requirements of this standard, identify every documentation and system gap, and build the compliance program that proves ongoing compliance at every inspection cycle.