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Local code requirements for smoke detectors vary greatly in different areas of the country, so it would be unrealistic to know each and every one. In many areas the building code only requires one smoke detector per floor usually placed in a hallway.
Only one smoke detector per floor should be considered the bare minimum and is really not sufficient to protect your family in the event of a fire. If a fire would start in a room with the door closed it would take too long for the smoke to reach a smoke detector placed in a hallway and would greatly reduce the amount of time you and your family have to escape. You should have a smoke detector in your hallway but you should have them in many other places also.
NFPA (National Fire Protection Association)
The NFPA (National Fire Protection Association) states that for proper smoke detection you should have a smoke detector in each smoke chamber. Simply put a smoke chamber is an area where smoke can accumulate in quantity before it can travel to the next area. Each and every room is a smoke chamber, and if any room has a partial wall coming down from the ceiling that is at least 24 inches, that room has two smoke chambers in it.
Range of Detection
Smoke detectors also have an effective range of detection; most are rated to cover a 30′ x 30′ area. If the room is larger than that two detectors will be needed and spaced properly.
The bottom line is that for fast fire detection with the best chance to escape you should have a smoke detector in every room including the attic and basement, but excluding the bathroom and kitchen. You should try to get one as close to the kitchen as possible but it should be in a area not effected by the smoke generated from cooking.
Points to Consider
Placing your detectors or optimal detection smoke detectors should be placed on the ceiling as close to the center of the room as possible, and no closer than 12 inches from a wall. If the detector must be placed on a wall the top of the detector should be 6 inches down from the ceiling. On a sloped ceiling they should be 3 feet from the highest point measured horizontally.
Now that you know how many smoke detectors you need and where to place them, what type of smoke detector offers you the best protection? There are two types of detection methods that smoke detectors use.
The ionization type smoke detector responds fastest to burning fires with hot open flame and small or invisible smoke particles, which is why it sounds during cooking. The second type is the photoelectric smoke detector, it responds best to slow burning visible smoke caused by smoldering fires.
Which one do you choose? Since you want to be alerted to invisible smoke and visible smoke you should choose both. In the past it was one or the other or you would have to install two detectors at each location, but today they make combination detectors that have both detection methods, they are the best choice.
It is also important that your smoke detectors be interconnected, this means that if one sounds they all sound. This is critical to wake everyone in the event of a fire.