from NFPA 72 2010 and 2013 edition
Any one requireing 520 HZ notification appliances in sleeping areas???
Per NFPA 72 2010 edition
For fire alarm system notification devices in “sleeping areas only”
18.4.5.3* Effective January 1, 2014, where audible appliances are provided to produce signals for sleeping areas, they shall produce a low frequency alarm signal that complies with the following:
(1)
The alarm signal shall be a square wave or provide equivalent awakening ability.
(2)
The wave shall have a fundamental frequency of 520 Hz ± 10 percent.
Any one requireing 520 HZ notification appliances in sleeping areas???
Per NFPA 72 2010 edition
For fire alarm system notification devices in “sleeping areas only”
18.4.5.3* Effective January 1, 2014, where audible appliances are provided to produce signals for sleeping areas, they shall produce a low frequency alarm signal that complies with the following:
(1)
The alarm signal shall be a square wave or provide equivalent awakening ability.
(2)
The wave shall have a fundamental frequency of 520 Hz ± 10 percent.