Most of us feel safer after we purchase a smoke alarm; we check to see if it works, replace the batteries and trust that when the time comes this device will save our lives. However, a new study released in July from Victoria University in Australia, “Waking Effectiveness of Alarms for Adults who are Hard of Hearing,” reveals that people with hearing loss cannot be so trusting of their smoke detectors.
According to the study, typical smoke detectors and other devices such as strobe lights and bed and pillow shakers failed to wake an alarming percentage of the population who had mild to moderately severe hearing loss in both ears. The participants, 38 male and female volunteers ages 18-77, were exposed to different intensities of each sample device across two, non-consecutive nights during slow-wave sleep – the deeper part of sleep. Despite the fact that all of the tested subjects were able to hear the 3100-Hertz (Hz) tone when awake, only 43 percent of them were awakened by the smoke alarms while asleep. The strobe lights at the lowest strobe light intensity, which is more intense than standards require, woke up only 27 percent of the participants with hearing loss. The bed and pillow shakers awoke 80 to 83 percent of the participants with hearing loss when used alone.
“It is desirable that any standard audible smoke alarm for the general population emit a signal that maximizes the chances of awakening hard of hearing people (provided such signal presents no increased risk to other sections of the population),” recommended study authors Dorothy Bruck and Ian Thomas.
According to Brenda Battat, associate executive director of the Hearing Loss Association of America (HLAA), “Consumers with hearing loss need to be educated about fire safety to avoid that false sense of security they have. They need to know that the fire alarms they currently own are probably not going to wake them up.”
The HLAA has long suspected that people have died in fires because they could not hear or wake up to high-frequency smoke alarms, but government investigations of fire fatalities have not inquired into whether the victims had hearing loss.
“This study shows there is a critical need for emergency warning systems to be redesigned or supplemented as soon as technically feasible,” says Terry Portis, executive director of HLAA. “Millions of people do not and will not know that they will not wake up to the high-pitched tones used by most emergency alerts. We call upon manufacturers of emergency alerting equipment, such as smoke alarms, carbon monoxide alarms and weather radios, to provide solutions that recognize this reality as soon as possible.”
The HLAA and other organizations have been working to make the changes in fire codes a reality for a long time but so far they have come up empty handed. The lack of resources and the resistance to change from the entities that set standards has been especially shocking, as this can be a matter of life and death.
“The industry doesn’t necessarily want to make changes if it means it will cost money. The solid research results we have now give us something definite to work from. It’s not easy to get change but the new research is going to help make it happen,” Battat says.
Smoke detectors aren’t a lost cause, however. A specific multiple frequency signal consisting of a 520 Hz square wave successfully alerted 92 percent of the subjects at the benchmark level of 75 decibels (dB) and alerted 100 percent at 95 dB.
A study presented this year proposed a viable solution of introducing more low-frequency devices, since they proved to be the most effective method for waking people up. Currently, the only product especially designed to emit lower frequency sounds for people with hearing loss, called the Loudenlow 520™ (www.loudenlow.com) is a stand-alone device that doesn’t integrate with other systems, which means the user may not become alerted until the smoke has reached the space where the device is installed – for example, a bedroom – by which time it may be too late for safe escape. The company is, nonetheless, to be commended for introducing the first low-frequency alarm.
“It’s feasible to produce improved, effective devices, and some companies are already developing them, but the issue is also getting them on the market at an affordable price. As soon as devices are labeled as being for a niche market the price goes up. There’s a need to get them out as mainstream products usable by everyone! We need to push for affordable alarms and more distribution and installation programs,” Battat explains.
The recent wildfires in California have been a wake up call of another sort. Getting word to people with hearing loss can be a challenge even when everyone is awake and attentive.
“We need a way to deliver emergency alerts instantaneously through a wide variety of outlets to reach people wherever they are and through whatever communication channel they use,” says Battat. “Nothing is going to be foolproof, so the more redundancy we build into an alerting system the more chance there is to reach people – whether it is through a buddy system, reverse 911 notification or messages sent directly to cell phones and pagers. The way to alert people has to be diversified because people have different needs and different communication channels. This is a big complex puzzle!”
For more information, visit the Web site of the National Fire Protection Association, www.nfpa.org, and search “waking effectiveness of alarms.”
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