Carbon Monoxide Safety

Carbon monoxide is a product of incomplete combustion. It is colourless, odourless and tasteless, and it binds to haemoglobin far more readily than oxygen does, which is what makes low concentrations dangerous over time and higher concentrations dangerous quickly.

• Cracked or corroded heat exchangers.
• Blocked, disconnected or undersized venting.
• Insufficient combustion air or a depressurized mechanical room.
• Dirty or misaligned burners and incorrect gas pressure.
• Unvented appliances, vehicles running in attached garages and portable generators.

Early exposure symptoms resemble influenza without a fever: headache, nausea, dizziness and fatigue that improve when occupants leave the building. Multiple occupants or pets affected at once is a strong indicator.

1. 1Turn on a personal carbon monoxide monitor before entering the building.
2. 2Take an ambient reading in the living space before starting any appliance.
3. 3Record ambient readings in the mechanical room and near each appliance.
4. 4Run the appliance and measure carbon monoxide in the flue gas with an analyser.
5. 5Repeat with the building in a worst case depressurization condition.
6. 6Document every reading with the conditions under which it was taken.

Alarm placement requirements, acceptable carbon monoxide levels, technician response procedures and notification obligations vary by jurisdiction, adopted code edition and the regulations in force.