NFPA 58: LP-Gas Code

NFPA 58 is the main safety code for liquefied petroleum gas (LP-gas, usually propane) in the United States. It covers how propane cylinders and tanks are built, placed, filled, moved and used, from a backyard grill cylinder to a large bulk plant. This page is a plain-language overview of the code’s ideas. It is not a replacement for the standard.

• Construction
• Fuel Handlers
• Facility Managers

Where NFPA 58 fits

• NFPA 58 is a voluntary consensus code from the National Fire Protection Association. It becomes enforceable when a state, city or fire marshal adopts it, which most do, in some edition.
• OSHA has its own LP-gas rules: 29 CFR 1910.110 for general industry and 1926.153 for construction. OSHA’s general industry rule incorporates NFPA 58 (an earlier edition), so following NFPA 58 usually satisfies it. See Propane and Temporary Heaters.
• The local authority having jurisdiction (AHJ), such as the fire marshal, decides which edition applies and may require more. Check with them.
• Related codes include NFPA 54 (the National Fuel Gas Code) for gas piping and appliances in buildings, and the International Fire Code. See International Fire Code (IFC) and NFPA 30.

Why LP-gas needs special rules

• Propane is stored as a liquid under pressure and boils into a gas that is heavier than air. Leaks sink and collect in low spots, such as basements, pits and trenches, where a spark can ignite them.
• Propane is naturally odorless. Suppliers add a strong odor (ethyl mercaptan) so leaks can be smelled, but odor can fade, and some people can’t smell it.
• A small amount of liquid expands into a lot of gas, and a leak or an overfilled container can create a large flammable cloud.
• Fire near a container can cause the pressure to rise, and, in the worst case, a boiling liquid expanding vapor explosion (BLEVE). Relief valves and distance are the protection.
• Liquid propane is extremely cold when released and causes freezing burns.

Containers: cylinders and tanks

• Built to standards: cylinders and tanks must be made, tested and marked as required (for example DOT cylinders and ASME tanks) and fitted with relief valves, gauges and other safety devices.
• Cylinders from small grill bottles to 100-pound cylinders are used for grills, heaters, forklifts and construction. They need valve protection (collars or caps), an overfilling prevention device (OPD) on common sizes, and regular requalification. Standard 20-pound cylinders generally must be requalified or replaced about 12 years after manufacture. See Home Propane Tanks.
• Tanks (ASME) are bigger, permanent or portable, and installed by licensed suppliers with specific siting rules.
• Damaged, dented, rusted or leaking containers must be taken out of service.
• Containers are filled only to a safe level, generally about 80 percent of capacity by volume, leaving room for expansion.

Where containers can be placed

NFPA 58 sets minimum distances between containers and buildings, property lines, sources of ignition and other hazards, and the distances grow with container size. In general:

• Outdoors and upright: cylinders and tanks are kept outdoors, on firm, level ground, with the valve up and protected from damage and vehicles. Small cylinders used for portable appliances can be used inside under certain limits, but storage inside buildings is restricted.
• Distances: the code gives separation distances from buildings, openings, air intakes, ignition sources and property lines. The numbers depend on container size and type, so use the tables in the current edition and your local rules, and the supplier’s instructions.
• No storage in unsafe places such as basements, below grade, near stairways or exits, or in vehicles left in the sun.
• Protection from heat and impact: keep containers away from heat sources, and use barriers such as bollards in traffic areas.
• Cylinder storage: the code limits quantities in storage areas, requires separation of full and empty cylinders from other hazards (such as oxygen cylinders), and calls for warning signs, no-smoking rules and fire protection. See Compressed Gas Cylinders.

Filling and transfer

• Only trained, qualified people fill cylinders and tanks, using approved equipment and procedures. Customers should not fill their own cylinders from bulk tanks, and untrained filling is dangerous.
• Weigh or gauge the fill and don’t overfill. Use proper fill limits and bonding or grounding as required.
• Control ignition sources during transfer: no smoking, sparks, running engines nearby or open flames. Keep the area ventilated and clear of drains and low spots.
• Check for leaks after filling. Use soapy water or a leak detector, never a flame. See Gas Leaks.
• Have fire extinguishers, usually dry chemical, available. See NFPA 10: Portable Fire Extinguishers.

Transporting cylinders

• Secure cylinders upright, in a well-ventilated vehicle area, with valves closed and protective caps or plugs on. Don’t leave them in a hot, closed car.
• Limit the number carried, and drive directly. Comply with DOT hazmat rules for larger loads. See DOT Hazmat and Hazmat Placards.
• Keep the cylinders out of the passenger compartment where possible. See Loading Cargo & Roof Racks.

Connections, regulators and appliances

• Use regulators, hoses and fittings listed for LP-gas, and replace them when worn, cracked or damaged. Hoses have age limits.
• Keep connections tight, protected and leak-tested. Don’t modify fittings or use makeshift parts.
• Appliances must be installed and vented as required, with enough combustion air, and checked by qualified people.
• CO and gas detectors help protect people in buildings and RVs. See Carbon Monoxide and RV Safety.

Training and emergency response

• NFPA 58 requires that people who fill containers, transport LP-gas, install systems and service equipment be trained for their duties, with records. Many suppliers use certification programs, such as those from the Propane Education & Research Council. See Safety Certifications.
• Know what to do in a leak or fire: shut off the valve if it’s safe, evacuate, keep ignition sources away and call 911 and the supplier. See Emergency Action Plans.
• A cylinder involved in a fire should be left to the fire department.

Using NFPA 58 in your workplace

• Containers are listed, in date and undamaged; valves protected; relief devices intact
• Cylinders are upright, outdoors where required, and set back as the code and AHJ require
• Only trained persons fill and handle; no overfilling; ignition sources controlled
• Hoses, regulators and fittings are rated for LP-gas and leak-tested
• Signs, extinguishers and an emergency plan are in place; gas and CO detectors work
• I checked the edition my jurisdiction has adopted

Note: NFPA codes are copyrighted. This page summarizes them in general terms. Distances, quantities and requirements are detailed in the standard and local rules, so use the current edition.

Last updated: October 4, 2026