Commercial Kitchen Gas Supply Guide 2026: LPG vs Natural Gas, Supply Pressure, Injector Sizing & Getting Burners That Work on Site

A gas range that fired perfectly on the factory test bench can arrive on site, get connected by a licensed fitter, and still produce lazy yellow flames, sooty pan bottoms and a wok burner that will not sear. Nothing is broken. The appliance was simply built for a different gas than the one coming out of your wall.

Gas is the one utility that buyers routinely leave off the purchase order. Voltage gets specified. Water gets tested. Gas gets a single word — “LPG” or “natural gas” — and that word is not enough. This guide covers what a commercial kitchen equipment factory actually needs to know to build burners that work at your address: gas family, supply pressure, injector sizing, pipe capacity, altitude, and the safety devices your local inspector will look for.

What is the real difference between natural gas and LPG?

The difference is energy density, and it is far larger than most buyers expect. The number that matters is the Wobbe index, which describes how much heat a burner delivers through a fixed orifice at a fixed pressure.

• Natural gas (2nd family, G20/G25): Wobbe index roughly 45–55 MJ/m³
• LPG — propane (3rd family, G31): Wobbe index roughly 72–87 MJ/m³
• LPG — butane (G30): similar band to propane, different vapour pressure behaviour in cold weather

Propane carries roughly 1.5 to 1.8 times the energy of natural gas per cubic metre through the same hole. Put natural gas through a burner drilled for propane and you lose 40 percent or more of the rated output — the burner still lights, so nobody suspects the injector. Put propane through a burner drilled for natural gas and you get over-gassing: yellow tipping, soot, carbon monoxide risk and, on enclosed appliances, nuisance shutdowns.

This is why “convertible to LPG” on a spec sheet is meaningless unless the conversion kit — the correct injector set, and on many appliances a different pressure regulator and pilot injector — physically ships with the equipment.

What supply pressure will my equipment actually see?

Appliances are certified at a nominal inlet pressure. If your site delivers something different, the appliance is out of specification even with the correct injector. Typical nominal supply pressures:

Two numbers travel with every gas appliance and they are not the same thing. Inlet or supply pressure is what arrives at the appliance isolation valve. Manifold or burner pressure is what the appliance regulator delivers to the injectors, and it is the figure a commissioning engineer measures at the test point. Ask any supplier for both. A quotation that states only “LPG” and no pressure is a quotation that has not been engineered.

How much output does the wrong injector actually cost?

Burner heat input scales approximately with the square of the injector bore and the square root of the pressure. In practice, on our own production floor, that means:

• A 0.05 mm error on a small 0.85 mm injector shifts output by roughly 12 percent
• A wok burner drilled for 37 mbar propane and run on 20 mbar natural gas delivers well under half its nameplate kW
• Rated kW figures on competing quotations are only comparable if the gas and pressure behind them are identical

That last point is worth pausing on when comparing suppliers. A 22 kW wok burner quoted at 37 mbar propane and a 22 kW wok burner quoted at 20 mbar natural gas are not the same product. If you are still shortlisting factories, our guide to the top commercial kitchen equipment manufacturers in China is a useful starting point — and a fair test of any of them is whether they ask which gas you have before they quote a kW rating.

What should I put on the purchase order?

Six lines. They cost nothing to specify and they are close to impossible to fix after the container is sealed:

1. Gas family and type — natural gas G20, G25, propane G31, butane G30, or a stated LPG mix
2. Nominal supply pressure in mbar or kPa at the appliance, not at the tank or meter
3. Site altitude in metres above sea level
4. Connection type and size — thread standard and diameter, since a fitting mismatch stops commissioning as hard as a wrong injector
5. Whether the appliance regulator is supplied by the factory or by the local installer
6. Dual-fuel requirement, if the site may switch between piped gas and cylinders

Because our burners, manifolds and injector sets are machined in-house rather than bought in as finished assemblies, a gas configuration is a build parameter on the production order, not a modification after the fact. We can also fit dual-injector sets and label them, so an appliance ordered for piped natural gas can be switched to cylinder LPG by the site engineer without ordering parts from overseas. Custom manifold layouts and non-standard burner spacing are built to approved shop drawings with no tooling charge, on the same 25–45 day ex-factory schedule as the rest of the order — versus the 60–90 days typical when equipment is routed through a trading intermediary who has to send the specification back to a factory anyway.

How do I size the gas pipework for a commercial kitchen?

Undersized pipe is the second most common cause of “faulty” burners. The pipe is sized for the pressure drop it produces at peak simultaneous demand, not for the sum of every nameplate on the drawing.

• Add the gross heat input of all connected appliances in kW
• Apply a diversity factor — a hotel cook line rarely runs every burner at maximum simultaneously; 0.6 to 0.8 is a common planning band, but your gas engineer sets the figure
• Design so that the pressure drop from meter to the furthest appliance stays within the allowance for the system — on low-pressure natural gas installations that allowance is often around 1 mbar
• Size for the furthest and largest appliance, usually the wok range or the largest fryer bank
• Leave the appliance isolation valve, filter and test point accessible after the equipment is pushed into position

A useful cross-check: if your gas wok range alone is drawing 20–30 kW per burner, a pipe run sized for a light restaurant will starve it the moment the fryers also call for gas.

What safety components will an inspector look for?

Commercial gas appliances are held to a higher standard than domestic ones, and the components below are the ones that come up repeatedly at handover:

• Flame failure device (FFD) on every burner — a thermocouple or ionisation probe that closes the gas valve if the flame goes out. This is standard on compliant commercial equipment and is not an optional extra
• A proper gas train at the appliance: isolation valve, filter, regulator where applicable, and a pressure test point
• Gas–ventilation interlock — in the UK and in many specifications drawn from BS 6173 practice, the gas supply must shut off if the kitchen extract system is not running. Coordinate this with your kitchen ventilation and hood system at design stage, not at commissioning
• Combustion air provision — gas equipment needs make-up air, and a well-sealed modern kitchen with a powerful extract canopy can starve its own burners
• Documentation — the appliance data plate, declaration of conformity and test report should state the gas category and pressure the appliance was certified for. Our guide to equipment certifications covers which marks apply where

Does altitude change the specification?

Yes, and it is routinely missed on projects in Nairobi, Addis Ababa, Bogotá, Quito, Kabul and across the Andes and the East African highlands. Air density falls with altitude, so a burner tuned at sea level runs rich in thin air.

A widely used planning rule is a reduction of roughly 4 percent in heat input per 300 m above about 600–700 m, corrected by fitting smaller injectors. At 1,800 m — Nairobi’s elevation — that is a meaningful derate, and the difference between a fryer that recovers between baskets and one that does not. Tell your factory the altitude and the injectors can be selected before the appliance ships.

Indicative FOB prices for gas-side components

These are small numbers next to the equipment they protect, which is exactly why they should ship with the container. Spare injector sets for both gas types, spare thermocouples and a spare regulator per appliance family travel with our orders as standard, and the burner assembly and gas valve carry a two-year written warranty with the replenishment source named in the order documents. A wok range idle for three weeks waiting on a USD 9 jet is not a warranty problem — it is a packing list problem.

Frequently asked questions

Can the same appliance run on both natural gas and LPG?

Most commercial gas appliances can, provided the correct injector set is fitted and the appliance regulator suits the new pressure. What is not interchangeable is the hardware — you cannot drill a jet on site and expect a certified result. Order the conversion kit with the appliance and keep it taped inside the appliance cavity.

My site has natural gas but supply is unreliable. What should I specify?

Specify dual-fuel and install an LPG cylinder bank with a changeover regulator as backup. Tell the factory at order stage so both injector sets ship and the data plate reflects both configurations. This is common practice in markets where piped gas coverage is patchy.

Is a higher kW rating always better?

No. Higher input needs more gas flow, larger pipe, more combustion air and more extract capacity. An over-specified cook line on undersized pipework performs worse than a correctly matched one, and burns more gas doing it. Match burner input to the menu and the flue capacity.

Do electric appliances avoid all of this?

They trade gas questions for electrical ones — supply voltage, frequency, phase and cable sizing. Those have their own failure modes, covered in our commercial kitchen equipment voltage guide. Most hotel kitchens end up mixed, which means both sets of questions need answering on the same order.

Who should commission gas equipment on site?

A gas engineer licensed in your jurisdiction, working from the appliance manual and measuring manifold pressure at the test point. Factory settings are a starting point; final adjustment is always local. Ask for the commissioning sheet with recorded inlet and manifold pressures for each appliance and keep it with the O&M file.

Get the gas specification right before the order is placed

Send us your gas type, measured supply pressure and site altitude with your equipment list and we will confirm injector sizing and regulator requirements per appliance as part of the quotation. Get a free quotation within 24 hours — [email protected] or WhatsApp +86 158 1364 3427.