Fire: Smoke Alarm Types & the Law

Vancouver firefighters remind residents that a smoke alarm (also called a smoke detector) can give an early warning of a fire, significantly increasing your chance of escape and survival. They work effectively, around the clock, and are among the most important safety measure in the home.

Different types of smoke alarms

Smoke Alarm Graphic

There are two types of smoke alarms, ionization and photoelectric. Both types are UL approved and have close activation times.

  • Ionization smoke alarms monitor "ions" or electrically charged particles. Smoke particles change the electrical balance of the air. The alarm will sound when the change in electrical balance reaches a preset leve1. (IFSTA Fire and Life Safety Educator Pg 38)
  • Photoelectric smoke alarms use a beam of light and a light sensor. Smoke particles change the amount of light that reaches the sensor causing the alarm to sound. (IFSTA Fire and Life Safety Educator Pg 39)

To learn the nuts and bolts about about how smoke alarms work, visit http://www.howstuffworks.com/smoke.htm

Heat detectors are best used over hazards where flaming fires could be expected such as a garage or utility area. Heat detectors have a slower response than smoke detectors according to the National Fire Protection Association because heat generated by small fires tends to dissipate fairly rapidly. (NFPA Fire Protection Handbook Page 5-20, 5-58&59).

The law on smoke alarms

Washington State Requirements for All Homes: The Uniform Building Code has required smoke alarms/detectors in all dwellings since the 1973 edition of the code. Currently, all new dwellings are required to have hard-wired, interconnected smoke detectors with battery back-up on each level of the home as well as in each bedroom.

Washington State Requirements for Rentals: In homes and apartments used as rentals, the Washington Administrative Code (WAC) Section 212-10-045, Item 2 states: "It is the responsibility of the owner of each existing building, mobile home or factory-built housing to install smoke detection devices within each dwelling unit occupied by persons other than the owner." Item 3 states: "It is the responsibility of the owner of each new or existing building, mobile home or factory-built housing, containing dwelling units occupied by persons other than the owner, to inspect and test all smoke detection devices at the time of vacancy and make the necessary repairs or replacements to insure that the smoke detection devices are operational prior to re-occupancy, and to instruct the occupants of the purpose, operation and maintenance of the smoke detection device(s)."

WAC 212-10-050 states: "It is the responsibility of the occupant of all new or existing dwelling units, owned by other than the occupant, to maintain and test all smoke detection devices installed within the dwelling unit by the owner. Actual costs of maintenance, repair or replacement of smoke detection devices shall be as agreed beforehand by the occupant and owner. However, failure of the owner to abide by the terms of any such agreement does not relieve the occupant to the penalty provisions of WAC 212-10-050."