Optimizing emergency awakening to audible smoke alarms: an update

This review examines research on arousal from sleep in an emergency. It considers whether the current smoke alarm signal is optimal for waking those most at risk of dying in a fire and, if not, how it may be improved.

The fire fatality rate during the sleeping period is approximately three times greater than at other times.

Four key areas are reviewed: (a) the characteristics of four signals (high-frequency beeping, Temporal 3, voice, and naturalistic sounds); (b) how human characteristics alter arousal to different signals; (c) research comparing the effectiveness of different alarms in different sleeping populations; and (d) acoustical, methodological, and theoretical implications.

Significant risk factors for staying asleep include high levels of background noise, being a heavy sleeper, sleep deprivation, being a child, hypnotics, alcohol intoxication, and hearing impairment. The high-frequency beeping signal was significantly less effective than either a voice alarm or mixed-frequency beeping in waking selected at-risk groups.

The alternative signals were more effective in arousing various groups of sleepers than was the high-frequency signal currently used in smoke alarms.

Replacement of the current smoke alarm signal with one of a lower frequency is likely to wake more people more quickly and save lives.