Room volume, vent sizing, and pressure risk — checked in under two minutes. Based on AS/NZS 5601.1 Section 6.
Gas appliances installed in enclosed rooms require adequate combustion air and ventilation. AS/NZS 5601.1 Section 6 sets minimum room volumes and permanent ventilation opening sizes based on the total gas input rating of all appliances in the space. Insufficient ventilation causes incomplete combustion, producing carbon monoxide — the primary safety risk with enclosed gas installations.
The requirements differ between room-sealed (balanced flue) appliances and open-flued appliances. Room-sealed appliances draw combustion air from outside, so they don't deplete room air. Open-flued appliances require combustion air from the room and are subject to stricter volume and ventilation requirements.
Use this when installing a gas appliance in a laundry, garage, cupboard, or any enclosed space, particularly where multiple appliances share the same room. The tool confirms whether the room volume is adequate and what size permanent ventilation openings are required — before the inspector asks.
From the data plate on the appliance or the manufacturer spec sheet.
Has a flue but draws combustion air from the room. Most common for older storage HWS, ducted heaters, and gas log fires. — AS/NZS 5601.1, Clause 6.4
Check these before you proceed. Not diagnostic — but if you see any of these, the room needs further investigation before an appliance goes in or stays in.
Staining or soot around the flue connection or draught diverter
Indicates possible flue spillage. Perform a spillage test. Check flue for blockage or disconnection.
Yellow or orange flame (should be blue)
Incomplete combustion — could mean insufficient air supply or burner issue. Do not ignore. Test CO levels.
Smell of combustion products in the room when appliance is running
Flue spillage or flueless appliance in inadequate ventilation. Shut down and investigate. Check flue draught and room ventilation.
Occupant reports headaches, nausea, or dizziness when appliances are on
Possible carbon monoxide exposure. This is an emergency. Shut down the appliance, ventilate the space, and test for CO immediately.
Heavy condensation on windows when appliance is operating
May indicate combustion products are staying in the room (flueless appliance) or flue spillage (open-flued). Check ventilation adequacy.
Flue pipe is damaged, disconnected, or has visible holes/corrosion
Combustion products are escaping into the room. Do not operate the appliance. Repair or replace the flue before use.
Combustible materials stored against or near the appliance
Fire risk. Check manufacturer clearance requirements and AS/NZS 5601.1 clearance tables. Remove stored materials.
Ventilation openings blocked, covered, or sealed over
Common issue — homeowners block vents for draughts or insulation. Vents exist for a reason. Reopen and explain why to the occupant.