National Fire Alarm Code Update Benefits People with Hearing Loss

June 2009

Editor: Recent studies have shown that a low frequency fire alarm is more effective at waking people with hearing loss than a high frequency alarm. Now the alarm codes have been updated to reflect that reality. More information is in this press release from Lifetone Technology, one of the companies that manufactures low frequency alarms.


Smoke alarms have saved countless lives, but fire risks remain for the millions of Americans who may not wake up to the alarms while sleeping, such as those with hearing loss, children, heavy sleepers, and older adults. With the passage of a new code provision by the National Fire Protection Association (NFPA) that requires a lower-frequency signal, these individuals will have a stronger chance of waking up when a fire occurs.

The 2010 edition of NFPA 72(r) National Fire Alarm Code includes a provision that will require use of a low-frequency (520 Hz) square-wave signal for fire alarms installed in residential bedrooms of those with mild to severe hearing loss by January 2010, and in all commercial sleeping rooms by January 2014. This sound is a much lower frequency than the 3100 Hz pure tone sound of current smoke alarms and has been proven most effective at waking people up during a fire. With as many as 70 million Americans(1) having high-frequency hearing loss, this is a significant step to address a critical safety issue.

“Recent studies have shown that, even though many people may hear the smoke alarm when they are awake, the sound may not wake them when sleeping,” said Dr. David Albert, chief technology officer and chairman of the board for Lifetone Technology(TM). “A measure that all homeowners can take to ensure their family’s security is to consider additional UL-listed safety items designed to address the safety gap. For example, the Lifetone HL(TM) Bedside Fire Alarm and Clock already features the newly required 520 Hz square-wave signal that will wake people up during a fire, and it meets rigorous UL safety standards.”

Fire alarm signal studies(2) commissioned by the U.S. Fire Administration and the Fire Protection Research Foundation, an affiliate of NFPA, demonstrated that a 520 Hz square-wave signal is proven to be most effective at waking people with hearing loss, heavy sleepers, older adults and children — waking 92 to 96 percent of these individuals. The low-frequency signal was 63 to 69 percent more effective at waking children, heavy sleepers and people with hearing loss than current high-pitched alarms.

“The move by NFPA to include this provision in the National Fire Alarm Code speaks to the vital importance of ensuring that alarm signals are optimized to save lives,” Albert said.

About the Lifetone HL Bedside Fire Alarm and Clock

The Lifetone HL works with current standard smoke alarms and includes the technologies proven most effective at waking people up during a fire. The Lifetone HL “listens” for the sound of standard smoke alarms. When a smoke alarm is triggered, the Lifetone HL generates a loud 520 Hz square-wave signal at the pillow, breaking through sleep more effectively than standard smoke alarms. And since strobe light alarms awoke only 27 percent of participants with hearing loss, while bed shakers awoke 80 to 83 percent of participants with hearing loss, the product also includes a bed shaker that produces strong, intermittent vibration. This feature will aide those with profound or fluctuating hearing loss at 500 Hz and higher who may not reliably hear and wake up to the 520 Hz square-wave signal alone. The Lifetone HL is listed for UL Category UTGT as an accessory.

About Lifetone Technology

Lifetone Technology is dedicated to introducing technologies in products that improve life safety in fire, carbon monoxide and other life threatening emergencies. For more information, visit

(1) Based on Johns Hopkins study published in Archives of Internal Medicine July 2008; and Cruickshanks et. al. Beaver Dam study published in American Journal of Epidemiology, 1998.

(2) For links to fire alarm signal research studies, view the Resources in the Information Center at

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