Fire alarm notification appliance
A notification appliance may use audible, visible, or other stimuli to alert the occupants of a fire or other emergency condition requiring action.
In general, no common standard at that time mandated any particular tone, or pattern for audible fire alarm evacuation signals.
[citation needed] From NFPA 72, 2002 Edition: “7.4.2.1* To ensure that audible public mode signals are clearly heard, unless otherwise permitted by 7.4.2.2 through 7.4.2.5, they shall have a sound level at least 15 dB (Decibel) above the average ambient sound level or 5 dB above the maximum sound level having a duration of at least 60 seconds, whichever is greater, measured 1.5 m (5 ft) above the floor in the occupiable area, using the A-weighted scale (dBA).”[5] In 1970, Space Age Electronics introduced the first visual notification appliance, the AV32 light plate (which was installed over an existing horn) and V33 remote light.
In the United States, the 1990 Americans with Disabilities Act (ADA) triggered changes in evacuation signaling methods to include the hearing impaired.
Audible notification appliances would now have to include strobe lights with higher brightness intensity to alert the hearing impaired.
Voice evacuation alarms typically are not as loud as horns or bells (although generally standards require the same minimum sound pressure levels), and usually sound an alarm tone (typically a slow whoop, code-3, or chime tone, although this depends on the country and particular application) and a voice message warning that an emergency has been reported and to evacuate the building (often also directing occupants to not use elevators).
In 1973, the Autocall fire alarm company (merged to SimplexGrinnell then relaunched), manufactured the first voice evacuation system.
[6] In Europe, voice evacuation systems are normally a mandatory requirement for rail and air transport terminals, high-rise buildings, schools, hospitals, and other large facilities[citation needed].
From 2005 to 2007, research sponsored by the NFPA focused on understanding the cause of a higher number of deaths seen in high-risk groups such as the elderly, those with hearing loss, and those who are intoxicated.
[7] Research findings suggest that a mid frequency (520 Hz) square wave output is significantly more effective at waking high-risk individuals.
The Chapter 18 committee chose to apply the requirement to all sleeping areas – not just those where occupants have self-identified as having a hearing impairment.
