Smoke Detectors

A properly installed and maintained smoke alarm is the only thing in your home that can alert you and your family to a fire 24 hours a day, seven days a week. A working smoke alarm significantly increases your chances of surviving a deadly home fire.

  • Install both ionization and photoelectric smoke alarms, or dual sensor smoke alarms, which contain both ionization and photoelectric smoke sensors.
  • Test batteries monthly.
  • Replace batteries in battery-powered and hard-wired smoke alarms at least once a year (except non-replaceable 10-year lithium batteries).
  • Install smoke alarms on every level of your home, including the basement. The U.S. Fire Administration recommends installing smoke alarms both inside and outside of sleeping areas.
  • Always follow the manufacturer’s installation instructions when installing smoke alarms.
  • Replace the entire smoke alarm unit every 8 to 10 years or according to the manufacturer’s instructions.
  • Never disable a smoke alarm while cooking - it can be a deadly mistake. Open a window or door and press the “hush” button, wave a towel at the alarm to clear the air, or move the entire alarm several feet away from the location.

Smoke Detector Placement

Where you place smoke detectors depends on the size and layout of your home, and where people sleep in your home. Since the primary job of a smoke detector is to awaken sleeping persons and warn them of urgent danger, put a detector in each sleeping room and place additional detector(s) in the hallway or area by the bedrooms within five feet of the door to these rooms. In a house where the bedrooms are upstairs, one additional detector should be near the top of the stairs to the bedroom area.

Don't put detectors within six inches of where walls and ceilings meet, or near heating and cooling ducts. Detectors located in these areas may not receive the flow of smoke required to activate the alarm.

Sleeping Area

In homes with more than one sleeping area on the same level or on different levels (top), smoke detectors should be installed to protect each separate sleeping area and in each sleeping room.


Smoke detectors don't need much attention. Regular testing and prompt replacement of batteries are all that is needed. Batteries will last approximately one year. If your battery-powered detector begins to emit its low-power warning sound (usually short beeps), remove the weak battery and replace it immediately with a fresh one. Have a new battery on hand always. However, if you neglect these requirements, your detector won't do its job if a fire starts.

Contact Information

Feel free to contact the Fire Prevention Bureau at 650-286-3350 for assistance with proper placement of smoke detectors. If you are interested please call 724-745-1010.