Young adults impaired by alcohol were less likely to wake to emergency alarms, according to a study released by the National Fire Protection Association's Fire Protection Research Foundation. The effectiveness of most sounding alarms decreased when individuals were alcohol impaired and asleep; alternative non-sounding methods also were found not to be effective for waking this group.

Studies across young and middle-aged adult groups have consistently shown that alcohol impairment is a key factor in over half of the fire fatalities in the United States, United Kingdom and Australia. The study, Waking Effectiveness of Alarms for the Alcohol Impaired, examined how alcohol consumption influenced the waking effectiveness of several auditory and alternative signaling devices on a group of 32 young adults aged 18 to 26.

“Being alerted to an emergency is a vital first step in being able to survive it — studies like this one provide valuable information that will surely impact improvements in fire alarms in the future,” said Kathleen Almand, executive director of the Fire Protection Research Foundation. “Many people that are under the influence of alcohol die in fires — it is important to understand what works best when alerting someone to an emergency when they are impaired by alcohol and asleep.”

Some auditory signals were found to be an effective means of waking moderately alcohol impaired young adults from deep sleep. The study found that two lower-frequency alarm sounds (400Hz and 520Hz) were significantly more effective than the higher frequency alarm sound (typically 3,150Hz) commonly used in smoke alarms and other alerting appliances. Using the minimum sound level (loudness) permitted by code for sleeping areas (assuming minimal background noise), these lower frequency alarm sounds proved sufficient to wake participants, most within the first 10 seconds.

“Low-frequency signals have been more effective for waking high-risk groups in several similar studies which is something that we will be investigating in the future,” said Almand.

Alternative methods not effective in waking individuals were bed-shaker and pillow-shaker devices, which only awoke 58-65% of the group, used at the intensity level of the device as purchased. Strobe lights were also not effective, with only 24% waking at the lowest strobe light intensity.