Fire Safety Science Digital Archive

This paper assesses the waking effectiveness of strobe lights and pillow and bed shakers as smoke alarm warning devices and compares them to an auditory signal. The signals were activated at increasing intensity levels during slow wave (deep) sleep in two groups, (i) 38 adults aged 18-77 years with hearing loss of 25- 70 dBA in both ears, and (ii) 32 young adults aged 18 -26 years impaired with alcohol at 0.05 blood alcohol content. Three quarters of both groups slept through the strobe light activated at above the intensity required by the standard whereas a 75 dBA 520 Hz square wave T-3 sound woke over 90%, and at a louder volume 100%. The pillow and bed shakers did not wake 17-20% of the hard of hearing participants at the intensity level as purchased. Hard of hearing participants aged ?60 years were less likely to wake up to the bed shaker than those aged <60 years. The pillow and bed shakers tested were not an effective means of waking moderately alcohol impaired young adults from deep sleep, with 36%-42% not waking up at the intensity level as purchased. For both groups the pillow and bed shakers were less effective than the 520 Hz square wave T-3 sound at 75 dBA at the pillow. This study supports earlier research showing that when sleep stage is assessed strobe lights have poor waking effectiveness. The 520 Hz square wave sound was more effective than the non-auditory signals for both groups.