It’s important to understand that you can’t just connect any ole’ BBQ to your household natural gas line. The gas you have running through your mains is setup differently to that of your LPG gas bottles. They operate at different pressure levels, use different valves and your BBQ may require different jets that can accommodate natural gas.
Connecting your LPG BBQ to your gas mains without checking its compatibility and converting it properly can cause real damage. Not only could it result in your BBQ performing poorly, but it can also cause gas leaks, carbon monoxide poisoning, damage to your BBQ and it’s a fire hazard.
That’s because the mains gas and bottled LPG gas have different compositions, are supplied differently, and have a different density. Natural gas is mostly made up of methane that’s supplied through your mains, generally by copper piping, while LPG is a mix of propane and butane, which has a higher energy content and is heavier and commonly supplied through a short gas hose directly to the BBQ. This means that LPG produces more heat. Most BBQs are designed for an LPG connection, so their setup is for dense, high heat.
Yes, you can run your BBQ off methane, or propane/butane gas, but it’s the way it’s connected that’s the most important thing to consider to ensure you’re BBQ is getting the right amount of static and dynamic pressure to function correctly and safely.
Static Pressure (Pressure at Rest)
Static pressure is the pressure of the gas when it is not flowing. Imagine the gas in the pipe as a stationary column. This pressure is measured when all gas appliances (like your BBQ) are turned off. It’s the maximum potential pressure available through the gas line.
When you're testing a newly installed gas line for leaks, you're primarily concerned with the static pressure. You pressurise the line with air or gas and then monitor a pressure gauge. If the pressure doesn't drop over a specific period, it means there are no gas leaks along the line. The gas is not moving, so there is no velocity component to the pressure.
This is a crucial safety test that must be performed by a professional gas fitter.
Dynamic Pressure (Pressure in Motion)
Dynamic pressure is the pressure that exists due to the motion of the gas as it flows through the pipe. It's the pressure that is used to move the gas from one point to another; pressure gets converted into kinetic energy, or energy in motion.
When you turn on your BBQ burners, gas begins to flow. The pressure at the BBQs regulator will be slightly lower than the static pressure because some of that potential pressure has been converted to dynamic pressure to move the gas. The faster the gas flows, the higher the dynamic pressure and the lower the static pressure will be at the BBQ's regulator. This is based on Bernoulli's principle, which states that as the speed of a fluid increases, the static pressure within the fluid decreases.
Total Pressure
To understand the complete picture, there is also total pressure, which is the sum of static and dynamic pressure. In a closed system like a gas line, the total pressure should remain constant.
Total Pressure = Static Pressure + Dynamic Pressure
How does this relate to converting LPG to Natural Gas?
Understanding the significant difference in operational pressures for LPG or Natural Gas is important when converting your BBQ. LPG requires a higher operating pressure of about 2.75 kPa in Australia for BBQs, while natural gas requires about 1.1 – 1.5 kPa. A conversion may involve replacing the LPG regulator and potentially the gas piping and fittings to accommodate the lower static and dynamic pressure requirements of natural gas.
- Testing a gas line: During a pressure test, static pressure is checked to ensure the line is leak-free and can hold the required pressure before any appliances are turned on.
- Using your BBQ: When you light up your BBQ, you are now dealing with both static and dynamic pressure. The gas regulator on your BBQ is designed to take the incoming pressure (a combination of static and dynamic) and ensure a consistent, safe running pressure for the burners to operate correctly. A drop in pressure when all burners are on can indicate that the line is not adequately sized to provide enough gas for all the appliances, leading to low flames or poor performance.
This is why it’s imperative that you get a qualified gas fitter in to make any changes required for converting your LPG standard BBQ to Natural Gas. With a professional fitter, you know your conversion is compliant with safety and state standards with all the proper adjustments and checks completed, so when you light up your Natural Gas converted Sirius BBQ, you’re going to be grilling at the BBQs best.
What’s involved in converting your BBQ to natural gas?
All BBQs are different, so the following only applies to our Sirius BBQ range.
Our BBQs differ from your standard variety whereby our BBQ jets can be used for both LPG and Natural Gas (NG) connections. While they come with a standard LPG connection, with a few internal adjustments, they can be converted to NG, without needing to replace the jets as many other BBQs require.
Along with the BBQ jets adjustment, you will also need to fix a new gas hose and regulator, which can be purchased as part of our Natural Gas Conversion Kit. This will ensure your BBQ connection is set up for natural gas flow.
So, you need to:
- Change over the gas hose and shut-off valve to NG compatible versions; and
- Change the BBQ jets to accommodate NG
These two steps must be done for natural gas conversion, and they must be done by a qualified professional gas fitter or plumber!
