Carbon monoxide

Carbon monoxide (CO) is one of the by-products of natural gas combustion, the process that occurs in a gas heater. It is a colourless, odourless and tasteless gas that can cause death or serious illness.

Carbon monoxide poisoning can occur in any home or building with gas heating appliances. This includes newer models. Sadly, since 2010, three Victorians have died from carbon monoxide poisoning caused by open flued gas space heaters. Several incidents of non-fatal CO poisoning have also been documented over this period.

Service your gas appliance once every two years

The best way to make sure your heater or any gas appliance is safe is to have it serviced at least once every two years by a specialised plumber called a gasfitter. The gasfitter doing the servicing work must be registered or licensed in the specialised class of Type A appliance servicing.

As part of servicing your gas appliance, the gasfitter will test for carbon monoxide spillage and negative pressure – two key risks for CO poisoning.

If the gasfitter identifies CO spillage at your property, it must be rectified immediately as exposure to CO can put your life at risk. Your appliance may need to be repaired or disconnected.

If the gasfitter identifies negative pressure at your property, this also needs to be rectified. The gasfitter may need to install additional ventilation.

Use the right kind of gasfitter

For your appliance servicing, you should always use a gasfitter who is registered or licensed in Type A appliance servicing work.

You can ask the gasfitter about their qualifications and check the back of their ID card to make sure they are licensed or registered in Type A appliance servicing work.

If you are not sure if you are engaging the right type of gasfitter to undertake this work, you can check their type of licence or registration on our Find a practitioner tool.

After they have done the servicing work, the gasfitter must provide you with a compliance certificate if the total value of the work is $750 or more or involves removing the appliance from its fixed location, or if they make any modification to the gas piping. If your work needs a compliance certificate, this must be provided by a licensed gasfitter.

Ban on certain open-flued gas space heaters

As of 1 August 2022, certain open-flued gas space heaters (OFGSHs) can no longer be sold or supplied in Victoria unless they meet revised safety standards (AS/NZS5263.1.3 and AS/NZS5263.1.8).

The ban by Energy  Safe Victoria (ESV) under the Gas Safety Act 1997 affects any OFGSH that does not shut down automatically within 15 minutes if spillage of combustion products occurs under any negative pressure conditions. Combustion products include carbon monoxide, which can leak into living areas and cause serious health issues or death. The ban follows a recommendation by the Victorian Coroner that these appliances be phased out.

The Gas Safety (Gas Installation) Regulations 2018 have also been amended to prohibit the installation of these OFGSHs. Gasfitters who install or locate in premises an OFGSH which does not have the above safety features are in breach of the Gas Safety Act 1997.

Substantial penalties apply under the Gas Safety Act 1997 for the sale, supply and installation of these prohibited appliances.

For more information about the ban see the technical FAQs and consumer FAQs on the ESV website.

More detailed information about accepted (certified) OFGSHs can be found on the Gas Technical Regulators Committee website.

If you have an OFGSH already installed in your house or rental property before 1 August 2022, the ban does not apply to your OFGSH. However, VBA and ESV recommend that you have the OFGSH serviced at least once every two years by a qualified gasfitter to check it is operating safely.

There are other steps you can take to ensure safe operation such as not operating any extraction fans while the heater is on (this can result in negative pressure and draw in poisonous gases into living areas). You should also allow for adequate ventilation when the heater is operating. Consumer Affairs Victoria has some advice for consumers who have an OFGSH in their home.

Carbon monoxide spillage tests

Carbon monoxide should always leave a house through the heater’s flue. In appliances with an open flue, negative pressure can draw the carbon monoxide from the flue back into the room, rather than allowing it to escape to the outside. This can cause the levels of carbon monoxide to build up in the air.

The carbon monoxide spillage test checks the key areas of your gas heater and room for spillage. Your gasfitter will use a probe to check different parts of the heater and the room it is in to make sure there is no carbon monoxide in the air.

If your gasfitter detects carbon monoxide, they will take specific action to check whether the problem is caused by negative pressure or a fault with your heater.

If the carbon monoxide spillage cannot be rectified because there is a fault with your heater, the gasfitter must disable its operation. This might make you cold for a few days, but will keep you safe from the effects of CO.

Negative pressure tests

Negative pressure is created when extraction fans (including kitchen rangehoods) remove air from a building more quickly than it can be replaced. When this happens, air can be drawn back down your heater’s flue, causing carbon monoxide and other gases to enter the room (instead of being vented outside as they should be).

If your gasfitter identifies negative pressure, he will provide you with the following letter (PDF, 149.47 KB).

Please visit the website for more information on AS4575.

Important safety information about weather sealing/draught proofing properties where flueless gas space heaters and open flue gas space heaters installed

Weather sealing and draught proofing activities are often carried out to make homes more energy efficient. These activities may include the sealing of doors, windows, unsealed wall vents, evaporative cooler vents, chimneys, flues of open fireplaces and replacing/modifying wall or ceiling exhaust fans.

Special care needs to be taken if draught proofing and weather sealing your home that has any existing flueless gas space heaters or open-flued gas space heaters installed. These appliances require a certain amount of fixed ventilation to exhaust the products of combustion from the home and to operate safely. Weather sealing and draught proofing upgrades in these homes can reduce ventilation, thereby increasing the risk of carbon monoxide poisoning.

If you have had weather sealing products installed or draught proofed your home, the VBA recommends that you engage a licensed gasfitter to conduct a negative pressure and carbon monoxide spillage test for open flued gas space heaters and to check for adequate ventilation for flueless gas space heaters to ensure they remain safe. The VBA also recommends that you have your gas appliances regularly serviced by a licensed gasfitter.