Northbrook, IL – An Underwriters Laboratories (UL) Standards Technical Panel (STP) working group today released its recommendations for improving the effectiveness of smoke alarms in awakening children.
The not-for-profit product-safety-testing organization became aware of the issue last November after television stations in Milwaukee and Fort Worth, Texas, conducted nighttime fire drills at viewers’ homes to see whether children would be able to evacuate safely. Instead of evacuating, some of the children did not awaken to the sound of activated smoke alarms.
“When properly maintained, smoke alarms continue to be very effective warning devices,” says UL spokesman John Drengenberg. “But as effective as smoke alarms are, UL and the fire safety community are looking to see whether they can be made even more effective. If further research shows that’s possible, UL could change the requirements of its current smoke alarm standard.”
A purely mechanical fix might be hard to come by, however. According to Dr. Stephen Sheldon, associate professor of pediatrics at Northwestern University and director of the Sleep Medicine Center at Chicago’s Children’s Memorial Hospital, arousing children under the age of 10 can be difficult by any means, and awakening them sufficiently to evacuate a home in an emergency situation even more so.
The reasons, he says, are that children sleep much more deeply, sleep longer and have higher “arousal thresholds” than adults.
Sheldon co-chairs the UL STP research working group studying smoke alarms with Dr. Carole Marcus, professor of pediatrics at the University of Pennsylvania. Other working group participants include doctors, safety engineers, government officials, fire prevention and education specialists, and manufacturers.
Children under the age of 10 spend as much as 30 percent of their sleep time in so-called “slow-wave” sleep, explains Sheldon, which is characterized by increasingly slow brain activity, and from which it is difficult to awaken.
Adults may spend as little as 10 percent of their sleep time in slow-wave sleep and are therefore much more likely to awaken to smoke alarms, which are required to sound at 85 decibels from 10 feet away.
Children, on the other hand, have been shown to not wake up to alarms even as loud as 120 decibels – the threshold for hearing damage in humans.
While existing research indicates that some children in fact don’t awaken to the sound of smoke alarms, not enough research exists regarding alternatives. The STP working group recommends that the fire safety community pursue additional studies designed to investigate whether other sounds, such as recordings of parents’ voices; strobe lights similar to those used to alert the hearing impaired; physical stimuli, such as vibrations; or combinations of stimuli are more effective than the current alarms.
“There are many important and complex issues that need to be resolved in order to answer the question of what alarm design is best for awakening the sleeping child,” the report concludes.
The Consumer Product Safety Commission (CPSC), which participates in the UL smoke alarm STP, has already begun a two-year study to examine some of these questions.
“While future research may lead to the development of smoke alarms that are more effective in awakening children, current smoke alarms are a critical component in preventing injury or death in home fires,” says UL’s John Drengenberg. UL urges parents and caregivers to follow these tips in the fight against home fires.
- Install at least one smoke alarm on each floor of the house or residence and outside all sleeping areas. Some fire safety advocates recommend installing smoke alarms inside each sleeping area as well.
- Develop a home fire escape plan and practice it at least twice a year with all members of your household. (For help in developing your home fire escape plan, go to www.nfpa.org).
- Some individuals, particularly children, older people and those with special needs, may not wake up to the sound of a smoke alarm. You should be aware of this when developing your home fire escape plan.
- Working smoke alarms are needed in every residence. Test and maintain your smoke alarms at least once a month, or follow the manufacturer’s instructions. Smoke alarms most often fail to work because of missing, dead or disconnected batteries. Replace batteries at least once a year.
Editor’s note: For an electronic copy of the UL smoke alarm STP research working group’s report, go to www.ul.com/media/smokealarmreport.pdf.