The National Fire Protection Association (NFPA) established the Standard of installing Smoke Detectors. NFPA Standard 72 requires at a minimum that: 1. One Smoke Detector is installed on every level of a house.
2. One Smoke Detector is installed inside every sleeping room.
3. One Smoke Detector is installed in the hallway near sleeping areas.
Smoke Detectors can be installed on both the ceiling and the wall. When installing a Smoke Detector on the wall you should install it no closer than four inches to the ceiling and no farther than twelve inches below the ceiling. If you install a Smoke Detector on the ceiling, you should install it near the center of the room.