The technical guidance on this page reflects these published codes and standards, which your local authority (AHJ) adopts, amends, and enforces. It is educational, not engineering or legal advice — confirm the current requirements for your jurisdiction.
Commercial gas equipment burns one of two fuels: natural gas (NG), piped from the utility, or liquid propane (LP), delivered in tanks. City locations usually have natural gas at the meter; rural sites, food trucks, and buildings off the gas main run propane. A given appliance is set up for one or the other from the factory, and moving it to the other fuel requires a proper conversion — not just a different hookup.
The two gases differ in two ways that matter at the burner: energy density and supply pressure. Propane packs far more energy per cubic foot — roughly 2,500 BTU per cubic foot versus about 1,000 for natural gas — and it's delivered at higher pressure. To get the correct heat output, propane needs a smaller orifice (the metered hole feeding each burner) and natural gas needs a larger one.
| Property | Natural gas | Propane (LP) |
|---|---|---|
| Energy content | ~1,000 BTU/cu ft | ~2,500 BTU/cu ft |
| Typical appliance pressure | Lower (inches WC) | Higher (inches WC) |
| Orifice size | Larger hole | Smaller hole |
| Supply | Utility pipeline | Refillable tank |
Send high-pressure propane through a natural-gas orifice and you get dangerous, oversized flames, sooting, and equipment damage. Send natural gas through a propane orifice and you get weak, undersized flames. The fuels really are not swappable at the hose.
Most commercial gas equipment ships with a conversion kit — replacement burner orifices (spuds), sometimes pilot orifices, and a pressure-regulator spring or setting change. A qualified technician swaps the orifices, resets the regulator to the correct manifold pressure for the new fuel, and verifies the flame. Done correctly, the appliance delivers the same total BTU output as before on the new fuel. This is work for a licensed gas tech, not a DIY fix, and it should be checked with a manometer.
If natural gas is available at the site, it's usually cheaper per BTU and never runs out mid-service. Propane wins where there's no gas main, for mobile operations, and as a backup fuel. The equipment performs the same either way once it's set up correctly — the decision is about your site and supply. Size your total gas demand with the gas BTU load calculator, and if you're comparing fuel types broadly see gas vs electric equipment.
Equipment that's mis-set for its gas gives itself away at the flame. Watch for these before you assume the burner is broken:
A clean-looking blue flame after conversion, confirmed by a technician's manometer reading at the manifold, is the real proof the job was done right. Also note that at high altitude, burners may need de-rating regardless of fuel — another reason conversions belong with a qualified tech.
Tip: When you buy used or move equipment between sites, always ask which fuel it's currently set for. A range set for propane will misbehave on natural gas until it's converted — a quick, inexpensive fix if you know to ask.