Where to Install smoke detector alarm ?

Because smoke rises, place detector alarms high on a wall or on the ceiling. Wall-mounted units should be mounted so that the top of the alarm is 10 to 30 cm from the ceiling. A ceiling-mounted alarm should be connected at least 10 cm from the nearest wall.
In stairways with no doors at the top or bottom, place smoke detector alarms anywhere in the path of smoke moving up the stairs. Always set smoke detector alarms at the bottom of closed stairways, such as those leading from the basement.
The basic detection system should consist of one smoke detector alarm outside of each sleeping room and one additional smoke detector unit on each additional living level, including the basement and excluding unfinished attics, crawl spaces, etc. If hallways are longer than 40 feet between the sleeping and living areas, use two smoke detector alarms.
A good system should include both types of smoke detectors — one plug-in smoke detector and one battery-operated smoke detector. You might consider installing a photoelectric unit in the bedrooms of any family members who smoke.

Smoke detectors should not be located in the following areas:

• Kitchen, because of false alarms (burned food, cooking etc.).
• Garage, because of temperature extremes and false alarms.
• In front of air registers, open windows or open doors, because of false alarms caused by high air velocities.
• In or near attics, bathrooms, inside air ducts, unheated buildings, unheated motor homes, because temperatures may exceed typical limits of 32 to 100 degrees Fahrenheit.