To: Heads of Fire Departments
From: Stephen D. Coan, State Fire Marshal
Date: June 25, 2002
Re: Smoke Detector Location Guidelines for New Single Family Homes

This Office receives many inquiries regarding the placement of smoke detectors in single family homes. 780 CMR 3603.16.10 provides guidance on the number of smoke detectors. This section, in part, reads smoke detectors/heat detectors are required in the following locations:

  • In the immediate vicinity of the bedrooms
  • In all bedrooms
  • In each story of a dwelling unit, including basements and cellars, but not including crawl spaces and uninhabitable attics
  • In residential units of 1,200 square feet or more, automatic fire detectors, in the form of smoke detectors shall be provided for each 1,200 square feet of area or part thereof
  • Any smoke detector located within 20 feet of a kitchen or bathroom containing a tub or shower must be a photoelectric type

The 1996 edition of NFPA 72 gives further guidance on the placement of smoke detectors, when required. Some examples from Chapter 2 of NFPA 72 are provided:

  • In unfinished construction, detectors should be mounted on the bottom of floor joists
  • Smoke detectors in a room with a ceiling sloped greater than one foot in eight feet horizontally, should be located on the high side of the ceiling
  • Smoke detectors should not be located within three (3) feet of a door to a bathroom containing a tub or a shower or the supply registers of a forced air HVAC system

Further guidance is provided by NFPA 72 for dead air spaces. Smoke detectors can be located on the ceiling with the side of the detector greater than four (4) inches from the wall or on the wall of a room with the top of the detector located four (4) to twelve (12) inches down from the ceiling (see attached diagram from NFPA 72).

All smoke detectors should be installed in accordance with the manufacturer's recommendation and be UL listed.

If you have any questions please contact the Code Compliance and Enforcement Unit at 978-567-3300 or in Western Massachusetts at 413-587-3181.