A recent code requirement for low frequency fire alarms (520 Hz) in commercial sleeping spaces went into effect on January 1, 2014. We are still receiving many questions about changes to NFPA 72 (the National Fire Alarm Signaling Code) and wanted to share a helpful article on the topic.
Why the change? Studies have shown the low frequency signal is six to ten times more effective at waking children, heavy sleepers, and people with hearing loss than current high-pitched alarms, which operate at around 3 kilohertz.
The code change applies to new buildings with commercial sleeping spaces, such as hotels, dormitories, assisted living facilities (without trained staff responsible for waking patients) and apartments. The requirement may extend to those that are upgrading or retrofitting existing fire and life safety systems within those types of buildings, as well.