Smoke Detector Regulations in Massachusetts

On April 5, 2010, updated rules about the type and placement of smoke detectors went into effect in Massachusetts.  These regulations are enforced at the time of the fire marshal’s mandatory inspection prior to sale or transfer of a residence, so if you are planning on selling your home, or in the process of selling it, now is the time to make sure you are in compliance.

Photoelectric smoke detectors, which use light to detect smoke, are now required in Massachusetts — they are better at detecting slow-developing, smoldering fires, which lead to more deaths nationwide than faster, more blazing fires.  The older kind of smoke detectors, which worked via ionization, are still required, though with some changes.

For residences built before 1975, smoke detectors installed within 20 feet of a kitchen or full bathroom (with tub and/or shower) must be photoelectric.  Photoelectric smoke detectors are less likely to give false alarms from cooking smoke or shower steam than ionization smoke detectors, and are therefore less likely to be disabled by residents.

Smoke detectors beyond 20 feet from a kitchen or full bathroom must be “dual detectors” combining both ionization and photoelectric systems.  This provision of the law may be satisfied by installing a second photoelectric detector next to each existing ionization detector.

The 20-foot requirement also applies to combination smoke and carbon monoxide detectors — those within 20 feet of a kitchen or full bath must solely use photoelectric technology for the smoke detector.  Those beyond that limit may use ionization.

For homes built or brought into compliance with the building code after 1975, different rules as to number and location of and power source for smoke detectors may apply.  A consumer’s guide is available for download from the state Department of Fire Safety with more details.

How can you tell if your current smoke detectors are photoelectric or ionization?  Newer models should be labeled on the outside; if it is not labeled, it is likely older and therefore uses ionization.