Smoke and carbon monoxide alarms

Smoke alarms give people in a home or suite the early warning they need to get out of a fire. Carbon monoxide (CO) alarms warn of a gas that cannot be seen or smelled and can kill in a person's sleep. Both are required by building and fire codes in most homes in Canada, both need regular testing and both wear out and must be replaced.

Alarms versus detectors

The words are used loosely, but in codes they mean different things:

• A smoke alarm is a self-contained device that senses smoke and sounds its own built-in alarm. Alarms in a dwelling unit are often interconnected, so one sounding sets off all of them. They are listed to CAN/ULC-S531.
• A smoke detector is part of a building fire alarm system. It signals the fire alarm panel, which sounds alarms through the building and may call the fire department. See fire alarm system inspections.

Apartment buildings often have both: smoke alarms inside each suite, and smoke detectors in corridors and common areas connected to the building fire alarm.

Where they are required

The National Building Code of Canada and the provincial building codes set requirements for new construction and renovations. In general terms, current codes call for smoke alarms on every storey of a home, in or near each sleeping area, and increasingly in each bedroom, with alarms interconnected and hard-wired with battery backup in new construction. CO alarms are generally required where a home has a fuel-burning appliance or an attached garage, installed near sleeping areas.

Requirements for existing homes are set by the provincial fire codes and can be stricter than the rules that applied when the home was built. Ontario, for example, requires working smoke alarms on every storey and outside sleeping areas in existing homes, and CO alarms in homes with fuel-burning appliances or attached garages. Requirements in Alberta and BC differ in detail. Check the current rules in your province and municipality.

Landlord and tenant responsibilities

In rental housing, landlords generally must install the required alarms and keep them in working order, including testing them at set times such as at the start of each tenancy and replacing them when they fail or expire. Tenants generally must not disable alarms, and must tell the landlord if one is not working. Exact duties vary by province. Removing batteries or covering an alarm because of cooking smoke is unsafe and, in some provinces, an offence.

Testing and maintenance

• Test each alarm with its test button on a regular schedule, commonly monthly, and after any absence
• Replace batteries on the manufacturer's schedule, or when the low-battery chirp sounds
• Gently vacuum dust from alarm openings as the manufacturer recommends
• Never paint an alarm or cover it during renovations without removing the cover afterwards
• Check that interconnected alarms all sound when one is tested
• Note the manufacture or replace-by date printed on each alarm

Replacing alarms

Smoke and CO alarms have a limited life because their sensors degrade. Most manufacturers set a replacement date, commonly around ten years for smoke alarms and somewhat less for many CO alarms, and many newer alarms give an end-of-life signal. Replace any alarm past its date, any alarm that fails a test and any alarm whose age you do not know. Replace hard-wired alarms with compatible models so interconnection still works; this is a job for an electrician if wiring changes are needed.

Choosing alarms

• Look for the certification mark showing the smoke alarm is listed to CAN/ULC-S531, and the CO alarm to CSA 6.19.
• Combination smoke and CO alarms are available, but each function must be in the right location for its hazard.
• Alarms with strobes or bed shakers are available for people who are deaf or hard of hearing.
• Photoelectric smoke alarms are less prone to nuisance alarms near kitchens.

Common problems found during inspections

• Alarms missing from bedrooms, basements or new rooms added in renovations
• Expired alarms, or no date visible
• Batteries removed, or alarms disconnected because of nuisance alarms
• CO alarms missing in homes with gas furnaces, water heaters or fireplaces
• Alarms installed too close to kitchens, bathrooms or air vents
• Interconnection broken when one alarm was replaced

Fuel-burning appliances that are poorly maintained are the main source of CO. See a furnace maintenance checklist. Home buyers should also look at alarms during the inspection; see a home inspection checklist for buyers.

How ehZee can help

Through our fire inspections, verification and monitoring service, we help landlords and property managers review smoke and CO alarm coverage, condition, age and records across their buildings, and coordinate replacements with qualified contractors.

Common questions