If you’re fitting out a commercial kitchen — or even installing multiple gas appliances at home — it’s natural to wonder:
Can I connect more than one gas appliance to the same gas line?
The answer is yes, but with a very important warning: if it’s not designed properly, you can seriously reduce the performance and safety of your equipment.
Let’s break it down.
Can You Connect Multiple Gas Appliances to One Line?
Yes, you can — but only if the gas line is properly sized and installed.
Australian gas regulations (such as AS/NZS 5601: Gas Installations) allow for multiple gas appliances to be connected to a single line, provided:
- The total gas demand is correctly calculated
- The gas piping is appropriately sized for the load
- Pressure requirements for each appliance are met
Each appliance must still have its own isolation valve for safety and servicing.
How Poor Gas Line Sizing Reduces Appliance Performance
When multiple appliances are connected to a gas line that isn’t properly sized, you can face serious performance issues:
-
Low Burner Pressure:
Appliances won’t get enough gas pressure to operate correctly. Burners may sputter, fail to ignite, or operate weakly. -
Uneven Cooking:
Ovens, fryers, or combi ovens may not maintain consistent temperatures, leading to poor cooking results and slower service. -
System Failures:
Pilot lights might go out unexpectedly, or automatic shut-offs may engage, thinking there’s a fault. -
Increased Wear and Tear:
Running appliances at insufficient pressure over time can cause damage to components, reduce lifespan, and void manufacturer warranties. -
Safety Risks:
In extreme cases, an under-pressured or starved gas line can create dangerous backflow or cause incomplete combustion, producing carbon monoxide.
How to Properly Connect Multiple Gas Appliances
To safely connect multiple appliances, you must:
-
Calculate Total Gas Load:
Add up the MJ/h (megajoules per hour) or kW rating of every appliance to determine the total demand. -
Size the Gas Line Correctly:
The main gas line (and any branch lines) must be large enough to supply full pressure and flow to all appliances, even when they’re operating simultaneously. -
Install Pressure Regulators (if needed):
Some appliances require specific gas pressures. Regulators help maintain the correct delivery pressure even when multiple units are drawing gas. -
Use Isolation Valves:
Install an isolation valve for each appliance so they can be shut off individually for maintenance. -
Consult a Licensed Gasfitter:
In Australia, only a licensed gasfitter can legally install, modify, or work on gas systems. DIY is not an option for safety and compliance reasons
Quick Example
Imagine you’re installing:
- A 6-burner cooktop (50 MJ/h)
- A combi oven (75 MJ/h)
- A fryer (90 MJ/h)
Total gas demand = 215 MJ/h.
If the existing gas line was only rated for 120 MJ/h, your equipment would underperform, struggle to maintain pressure, and possibly shut down during peak use.
You would need a newly sized main line capable of handling the 215 MJ/h plus a margin for safety.
Final Advice
Yes, you can put multiple gas appliances on the same gas line, but only if it’s properly sized and installed.
Cutting corners will seriously reduce performance, shorten equipment life, and create major safety risks.
Always engage a licensed gas professional when adding or changing anything on your gas system — it’s not just smart, it’s the law.
