Optimizing smoke alarm signals: Testing the effectiveness of children\u2019s smoke alarms for sleeping adults

Gary A Smith,Mark Splaingard,Sandhya Kistamgari

doi:10.1186/s40621-020-00279-6

Abstract

BackgroundBeing asleep is an important risk factor for death during a residential fire; however, the high-frequency tone smoke alarms in many homes will not adequately awaken children who are old enough to self-rescue. In a series of previous studies, we identified smoke alarm signals that effectively awaken children 5–12 years old and prompt their escape. Because it is impractical to have separate alarms for children and adults in a household, the purpose of this study is to test whether alarms that are effective in awakening children and prompting their escape are also effective among adults.MethodsUsing a randomized, non-blinded, repeated measures design, 150 adults 20–49 years old were exposed during stage 4 sleep to four different smoke alarms. Statistical tests included the Kaplan-Meier estimator, generalized Wilcoxon test, and hazard ratios with Wald’s 95% confidence intervals.ResultsThe median age of study subjects was 30.0 years and 67.3% were female. Almost all (n = 149) subjects awakened and performed the escape procedure to all four alarms; one individual did not awaken or escape to the high-frequency tone alarm. The median time-to-awaken was 2.0 s for the high-frequency tone alarm and 1.0 s for the other three alarms. The median time-to-escape for the high-frequency tone alarm was 12.0 s, compared with 10.0 s for the low-frequency tone alarm and 9.0 s each for the female and male voice alarms. All pairwise comparisons between the high-frequency tone alarm and each of the other three alarms were statistically significant for the probability functions for time-to-awaken and time-to-escape. There were no significant differences in these outcome measures between the latter three alarms, except for female voice versus low-frequency tone alarms for time-to-escape.ConclusionsAll alarms performed well, demonstrating that smoke alarms developed for the unique developmental requirements of sleeping children are also effective among sleeping adults. Compared with a high-frequency tone alarm, use of these alarms may reduce residential fire-related injuries and deaths among children, while also successfully alerting adult members of the household.

Highlights

Being asleep is an important risk factor for death during a residential fire; the highfrequency tone smoke alarms in many homes will not adequately awaken children who are old enough to selfrescue
Arousing sleeping individuals and alerting them to the emergency in the event of a residential fire is important because the rate of fire-related mortality is three times higher during sleep, and about half of residential fire fatalities occur at night while the decedents are sleeping (Bruck and Ball 2007; Runyan et al 1992)
Compared with the high-frequency tone alarm, there were statistically significant differences in the probability functions for time-toawaken for the female voice alarm (Wilcoxon: p < 0.001; Hazard ratio (HR): 1.40, 95% Confidence interval (CI): 1.11–1.77), male voice alarm (Wilcoxon: p < 0.001; HR: 1.33, 95% CI: 1.06– 1.68), and low-frequency tone alarm (Wilcoxon: p < 0.001; HR: 1.50, 95% CI: 1.19–1.89) (Table 3)

Summary

Introduction

Being asleep is an important risk factor for death during a residential fire; the highfrequency tone smoke alarms in many homes will not adequately awaken children who are old enough to selfrescue. In a series of previous studies, we identified smoke alarm signals that effectively awaken children 5–12 years old and prompt their escape. Because it is impractical to have separate alarms for children and adults in a household, the purpose of this study is to test whether alarms that are effective in awakening children and prompting their escape are effective among adults. We initially demonstrated that an alarm using the voice of a child’s mother awakened 96% of children and prompted 83% to escape, significantly out-performing a high-frequency tone alarm (Smith et al 2006). That effective smoke alarm signals for sleeping children have been identified, it is important to test their effectiveness among adults because it is impractical to have separate alarms for children and adults in a household

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