Smoke alarms and smoke detectors shall not be installed within a 36-inch (910 mm) horizontal path from the supply registers of a forced air heating or cooling system and shall be installed outside of the direct airflow from those registers.
Guideline. The guideline in this case is that you shouldn't put alarms within 400mm of air conditioning vents or the blades of a ceiling fan, however we recommend 1m if possible.
- Within 3 feet of an air supply vent (supply or air flow) - Within 1 foot of a light fixture. - Within the “dead air space” where the wall meets the ceiling (ceiling smoke alarms must be at least 4” from the wall, wall mounted smoke alarms must be at least 4” and no more than 12” from the ceiling.
Annex A, A. 17.7. 4, recommends that detectors not be located in the direct airflow or closer than 36 inches from air supply diffuser or return air opening. This recommendation is intended to prevent airflow from diluting smoke or delaying smoke reaching the detector, both of which can significantly delay detection.
The International Mechanical Code requires a duct smoke detector in the return for units over 2000 cfm and requires a detector in the supply duct for systems over 15,000 cfm.
Avoid near fresh air vents, ceiling fans or very drafty areas (drafts can blow the smoke away from the detector/alarm). Avoid installing closer than 4 inches from the wall or corners.
Duct smoke detectors provide early detection of smoke and products of combustion present in air moving through HVAC ducts. These devices are designed for prevention of smoke recirculation in areas by the air handling systems. Fans, blowers and complete systems may be shut down in the event of smoke detection.
For many years NFPA 72, National Fire Alarm and Signaling Code, has required as a minimum that smoke alarms be installed inside every sleep room (even for existing homes) in addition to requiring them outside each sleeping area and on every level of the home. (Additional smoke alarms are required for larger homes.)
Do not site detectors less than 1m from air supply points or air circulating units. A device should not be mounted within 500mm of any obstruction.
Always choose an appropriate distance from all dampers, bends, and other dimensional changes in the duct system. Preferably, there should be a distance of three times the duct diameter before the source of interference and five times the duct diameter after the source of interference.
The blaring sound of the smoke alarm is always jolting, but if your Air Conditioner is causing your smoke alarm to go off, it is probably not the smoke, but a power surge that is causing this issue. If this is happening, unplug your air conditioner or shut off the circuit powering your AC unit.
Combustion particles form when fuel burns. Avoid kitchens, garages, and furnace rooms. Keep units at least 20 feet (6 meters) away from common sources of combustion particles. In small homes, where 20-foot distance is not possible, place the alarm as far away from fuel-burning sources as possible.
Install smoke alarms inside and outside every bedroom and sleeping area (like a hallway). Install on every level of the home, including the basement. A smoke alarm should be on the ceiling or high on a wall. Keep smoke alarms away from the kitchen to reduce nuisance, or false, alarms.
The most common application of the Point 7 Rule is smoke detectors in corridor applications. Applying the Point 7 Rule allows spacing between smoke detectors to be extended beyond 30 feet in corridors that are less than 30 feet wide.
Install smoke alarms in all circulation areas/ escape routes and high risk areas. Have at least one smoke alarm in every circulation space on each storey (such as hallways and landings) Position at least one smoke alarm in the principal habitable room (generally the living room)
However, there are specifications as to the location of each smoke alarm on a wall or ceiling: If mounted on the ceiling, it must be more than 4 inches from the wall. It cannot be closer than 4 inches or more than 12 inches from the ceiling if mounted on the wall.
Smoke alarms and smoke detectors shall not be installed within a 36 in. (910 mm) horizontal path from the supply registers of a forced air heating or cooling system and shall be installed outside of the direct airflow from those registers.
Smoke alarms and smoke detectors shall not be installed within an area of exclusion determined by a 10-foot (3.0 m) radial distance along a horizontal flow path from a stationary or fixed cooking appliance, unless listed for installation in close proximity to cooking appliances.
According to the United States Department of Homeland Security, and the California Building Code, at least one smoke detector needs to be placed in each of the following areas of your home: On Every Floor Level. In Every Bedroom. In Every Hallway Outside of a Bedroom.
Install a least one on every level of the home, including the basement. Place a smoke detector in every sleeping area. Ensure a smoke alarm is outside of every room, like in a hallway.
Have smoke alarms on every level of your home and in each bedroom and hallway. If you mount alarms on the ceiling, place them 4 inches from the wall. If your alarms are on the wall, they should be 4 to 12 inches from the ceiling. Don't install alarms near windows, vents, or drafty areas.
Place smoke detectors at least 3 feet from ceiling fans.
According to the NFPA, detectors should be located where air enters or leaves the duct system, and should be “installed in a way as to obtain a representative sample of the airstream.” (17.7. 6.5.
Peripheral devices, like smoke and motion detectors, door, and window sensors can either use AC power to function and require a battery only in case of a loss of power or can function as wireless devices which run independently and on battery power only.
NFPA 90A requires the first duct smoke detector to be installed on the supply side of air handler units of more than 2,000 cubic feet per minute (cfm) and requires one on the return side of units of more than 15,000 cfm and serving more than one story.