How Effective Are Smoke Alarms?

An interesting post at the Freakonomics blog calls into question the true efficacy of smoke alarms. As you read this please keep in mind that the author is a deputy fire chief with the Boston Fire Department:

Over this time period (2005–2009), no one died in this type of fire if the fire was big enough to operate the alarm.  If, using the same report, we only analyze “non-confined” fires, we get the following death rate per 100 fires for homes.

  • Smoke alarm present and operated – 1.15 (980 deaths / 85,100 fires)
  • No smoke alarm or alarm did not operate – 1.64 (1,640 deaths / 99,800 fires)

This is only a 29 percent reduction in death rate (1.15 versus 1.64). Given that some of the reduction is probably due to socioeconomic factors that accompany smoke alarm ownership, the reduction in risk attributable to the alarm is less than this percentage.  The numbers for apartments are even more troubling.

  • Smoke alarm present and operated – 1.17 (220 deaths / 18,800 fires)
  • No smoke alarm or alarm did not operate – 1.43 (200 deaths / 14,000 fires)

In apartments, smoke alarms only reduce the risk of dying in a fire by 18 percent (1.17 versus 1.42).