Smoke and CO alarm placement in Ontario

Verify before you install. This is a practical summary to help you specify the right alarms. The Ontario Building Code and the Ontario Fire Code are the authority, requirements differ between new construction and existing homes, and they are revised periodically. Confirm current requirements with your local authority having jurisdiction, and have hardwired work done by a licensed electrician.

Smoke alarms: where they go

The baseline in Ontario homes is an alarm on every storey, including finished basements, and outside all sleeping areas. A hallway serving several bedrooms typically needs one alarm covering that hallway, plus one per storey elsewhere.

Placement details that get missed on site:

• Keep alarms away from the immediate vicinity of bathrooms — steam produces nuisance alarms, and a nuisance alarm is the leading reason a detector ends up disconnected.
• Keep them clear of supply registers and ceiling fans; moving air can push smoke past the sensor.
• On a cathedral or sloped ceiling, mount down from the peak rather than at the apex, where a dead air pocket can form.
• Follow the manufacturer's stated distances from walls and corners. They differ between models and are part of the listing.

Interconnection

Interconnected alarms all sound when any one of them detects. In a two-storey house it is the difference between an alarm in the basement being heard in a third-floor bedroom and not being heard at all.

Interconnection is required in new construction, and retrofitting it is far easier during a rewire than afterwards. If you are opening walls for any other reason, run the interconnect conductor while you are in there — the cost during rough-in is trivial compared with going back later.

Carbon monoxide alarms

CO is a different problem from smoke and the placement logic differs. Ontario requires a CO alarm adjacent to sleeping areas in any home with a fuel-burning appliance, a fireplace or an attached garage. Homes that are entirely electric with no attached garage are generally outside the requirement.

Smoke rises; carbon monoxide does not. It has almost the same density as air and disperses fairly evenly through a room, which is why CO alarms can be listed for wall or ceiling mounting. Mount at the height the manufacturer specifies for that model rather than defaulting to ceiling height out of habit.

Combination units such as the BRK 7030BSLA hardwired smoke and CO alarm cover both in one device and one opening, which is usually the practical choice outside a bedroom corridor.

Photoelectric and ionization

The two sensing technologies respond to different fires. Photoelectric sensing responds faster to smouldering fires — upholstery, bedding, electrical insulation — which is the more common residential scenario and produces fewer cooking nuisance alarms. Ionization responds faster to fast-flaming fires.

Photoelectric is the sensible default for living areas and bedroom corridors. The BRK 7020BSLA hardwired photoelectric alarm is a straightforward option where you want smoke detection alone.

Every alarm expires

This is the requirement almost nobody checks. Alarms have a manufacturer's replacement date — typically ten years from manufacture for smoke, and often seven to ten for CO — printed on the back of the unit. Sensing elements degrade whether or not the alarm has ever sounded. An eleven-year-old detector that chirps and tests fine may not detect a fire.

Sealed ten-year battery units remove the annual battery change, which is the other common reason a detector gets disabled. Units with voice alert or an integrated strobe, such as the Kidde P4010ACLEDSCOCA-2 combination alarm with strobe, are worth specifying where an occupant is hard of hearing.

Testing

Test monthly with the test button, and replace the whole unit at the printed expiry date rather than at the first chirp. In rental property the obligations are stricter and sit with the landlord — check the current Fire Code requirements for your situation.

What to order

Browse smoke alarms, carbon monoxide alarms, and combination smoke, CO and strobe units.