Where NOT to install smoke alarms

There is plenty of information online and in product documentation as to where you need to locate smoke detectors and while there is information where not to locate the alarms, I do not think enough emphasis is made as to WHY you should not locate detectors in some areas.

Kitchens and Bathrooms

I think it is safe to assume that everyone has experienced the smoke alarm going off when you least expected. This issue is usually associated with Ion sensing smoke alarms. Charged particles from high heat sources such as ovens and toasters can travel a long way to trigger Ion sensing smoke detectors. Steam can trigger a photoelectric smoke alarm because to the detector smoke and heavy steam presents the same symptom. To avoid these common issues you should place smoke alarms at least 10 feet from kitchens and at least 5 feet away from a bathroom door where steam can roll out after a long hot shower.

Walls and Ceiling Corners / Peaks

When installing smoke alarms, never place them on an un-insulated outside wall. The temperature of the wall can vary enough to affect the operation of the detector. Never locate a detector with-in 4 inches of a corner or ceiling peak if vaulted. The corners of walls and ceilings can form dead air areas where smoke may not freely flow. Do not install wall mounted smoke alarms more than 12 inches down from a ceiling.

Air Ducts and Fans

Never locate smoke alarms near air duct vents or fans.  Detectors located to close to a cold air return or near a fan may not detect smoke due to air flow disruption. Stay at least 3 feet away from cold air returns, vents and the outer edge of a ceiling fan.  

Un-Finished Attics or Basements

False alarms can be more common in un-finished areas due to dust and insects clogging the sensing chamber. It is also best to avoid areas where temperatures may vary below 40 or above 100 degrees. Always follow manufacturer’s guidelines for proper installation locations. For these areas heat detectors are usually best. Heat detectors are not affected by dust but 110VAC hardwired units are still electronic and are susceptible to the varying temperatures. If you have a concern about unheated or cooled areas you should contact a local residential alarm company and inquire about a low voltage hardwired system. These systems use mechanical heat detectors which can operate anywhere.

Fuel Burning Source

When something burns it produces particles. Keep at least 20 feet away (unless isolated by a door) from stoves, furnaces, water heaters or other device that burns something. Again, heat detectors are ideal for these areas if you have a specific concern.