Smoke detectors must be mounted in an optimal place to perform the vital function of alerting the occupants of a building when smoke is present, indicating a fire has started. Certain detectors will not work if mounted to a wall while others will only work properly if mounted to certain locations on a wall.
Read the Directions
All smoke detectors come with a set of instructions, helping you to perform tasks like installing the batteries and testing the detector. The directions for each detector brand and model are different. Some smoke detectors are designed to only work mounted to a ceiling, while others can be mounted to either a ceiling or a wall. Consult the directions that came with your detectors to see if they are designed to work on a wall.
Reach of Children
For obvious reasons, you need to avoid any area of the wall that puts the smoke detector within the reach of children. If children are not normally in the building, the occasional visit from children can result in a tragedy later. Children are naturally curious and may end up damaging the detector, turning it off or moving it completely out of the area. Placing the smoke detector higher up the wall will also help avoid adults running into the detector accidentally, which can cause damage.
Dead Air Space
Six inches from where the ceiling and the wall meet each other is called the dead air space in a home. The dead air space sees little to no new air circulation during typical scenarios in the house. If new air does not reach the smoke detector regularly, the detector will not detect the presence of smoke as quickly. Mount the smoke detector on a wall at least 6 inches away from the ceiling but not more than 12 inches away, keeping the detector away from the dead zone but high enough to detect the smoke since smoke rises. Ceiling-mounted smoke detectors should be mounted at least 6 inches away from where the ceiling meets the wall.
Certain walls are not a good spot to mount a smoke detector. Avoid placing the detector in a kitchen since smoke from cooking will trigger false alarms. Detectors also should not be placed on the wall of a garage or any area of a house or building that is dusty since the dust will interfere with the detector's ability to operate correctly. Walls that have no insulation do not make a good mounting surface since the detector will experience extreme heat and cold, which will wear down the batteries sooner. Placing a smoke detector near a door, window or within 3 feet of an air exchange vent will also cause problems with the detector's operation because of constant air drafts passing over the detector.