Carbon Monoxide Detectors 101

Carbon Monoxide exposure may put your building at risk. Here’s how you can protect workers and occupants from this silent killer. 

Now that you’ve set your clocks back, it’s time to replace the batteries in your Carbon Monoxide (CO) detectors. Carbon Monoxide is a colourless, odourless, and tasteless gas that blocks oxygen from entering the bloodstream. It most commonly leaks from fuel-burning appliances such as furnaces, gas stoves and water heaters. 

For residential buildings, make sure to follow these requirements for Carbon Monoxide Alarms (NFC 6.7.1 & OFC 6.3.4.): 
  • CO alarms must be maintained in operating condition (OFC) 
  • Alarms must be located in the sleeping area of all homes/residential units 
  • Landlords of residential buildings are required to give each tenant a copy of the manufacturer’s maintenance instructions for the carbon monoxide alarm (OFC) 
  • Landlords are required to test carbon monoxide alarms whenever tenants change or the battery is replaced (OFC) 
  • CO alarms must be inspected, tested and maintained according to the manufacturer’s instructions (NFC) 
  • For residential buildings that contain a storage/parking garage, CO alarms should be installed next to each residential suite that is directly adjacent (via a shared wall/floor/ceiling) to the garage area
  • Alarms must be permanently connected to a closed electrical circuit with no disconnect from the power source 
  • Alarms are permitted to be battery-operated when an electrical power source is unavailable 
    • For battery-operated alarms/detectors, remember to change the batteries every six months. Daylight Savings Time is commonly recommended as a reminder to put new batteries in your Carbon Monoxide detector 
  • Each individual alarm must be wired to activate all other alarms when CO is detected 
  • Alarms must be audible in the bedroom of each suite even when doors are closed 
For non-residential buildings with parking garages: 
  • The garage must use natural or mechanical ventilation to limit CO concentration in air to below 100 parts per million as measured within 90 to 180 cm from the floor if most vehicles being stored are gas-powered rather than electric 
  • Ventilation systems must be controlled automatically by CO monitoring devices and systems that are activated when the above concentration is reached 
  • Adjacent rooms can only be ventilated through the garage as long as they produce no exhaust that affects overall air quality and are equipped with CO detectors 

When it comes to Carbon Monoxide exposure, Commercial and Industrial Buildings are mainly beholden to other regulations, including the Occupational Health and Safety Act (OHSA), Occupational Exposure Limits (OELs), and Part X of the Canada Occupational Health and Safety Regulations under the Canada Labour Code, Part II. Your company should also have a specific Health and Safety Program with policies and procedures for CO exposure that has been tailored to your property. Here are a few you should ensure are implemented at your building as a best practice and due diligence: 

Educate your Staff 
  • Workers should be informed about the health effects of CO exposure, sources of workplace CO, and the precautions they must take to ensure they are not exposed 
  • Workers should not be allowed to work alone in places where CO may accumulate 
  • Workers must know how to safely operate fuel-powered equipment 

Test the Air Quality of your Building 
  • A direct-reading instrument should be used to test the air and warn workers if CO levels are dangerously high. Most buildings secure third party vendors to perform indoor air quality testing on a regular basis. These results should be made available to the health & safety committee. 

Ensure Proper Ventilation Systems are in Place 
  • Take care to ensure work areas are well-ventilated
  • In applicable situations, use exhaust hoses to vent engine exhaust out of work areas 
  • If these measures are insufficient for adequate ventilation, a supplied-air respirators must be provided for workers 

Despite non-residential buildings being exempt from most of the requirements for Carbon Monoxide detectors in residential dwellings, CO still poses a threat to their occupants. If your building uses fuel-burning tools, equipment, or appliances, be sure to follow the guidelines outlined above to protect staff and other occupants from this dangerous gas. 

National Fire Code (NFC) 
Ontario Fire Code (OFC) 
Ontario Building Code (OBC)