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Lowdown on Latest Low Frequency Requirements

The wording of the 520Hz signal requirement in NFPA 72: 2010 and 2013 has caused some confusion. In general, low frequency sounders take the place of standard sounders in commercial sleeping spaces. However, there’s far more to know about the newly enacted requirement.

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It is very common to have a building fire alarm system with smoke alarms installed in the sleeping rooms of Group R-1 and R-2 occupancies. Section 907.2.9 of the 2012 IFC requires Group R-1 and R-2 occupancies to have a fire alarm system that activates the occupant notification system throughout all occupied areas of the building, including sleeping areas with dwelling units, by either pull stations or a sprinkler system. That means the low frequency signal (activated by the building fire alarm system) is required in all sleeping rooms.

The 2015 edition of NFPA 720 is expected to have identical provisions to those in NFPA 72: 2013, including the expansion of the requirements for tactile notification

Section of NFPA 72: 2013 exempts smoke alarms, installed in the sleeping rooms, from the low frequency signal requirement. In this application, there will be two signals in the sleeping rooms:

  1. Low frequency signal activated by the fire alarm system
  2. The standard 3kHz signal from the smoke alarm

In addition, the changes in NFPA 72 for low frequency smoke and fire alarms in sleeping rooms also prompted new provisions for sleeping spaces, including additional changes for the hard-of-hearing and profoundly deaf communities in NFPA 720, The Standard for the Installation of Carbon Monoxide (CO) Detection and Warning Equipment. NFPA 720: 2012 has identical provisions for notification devices (i.e., low frequency and tactile) in residential sleeping rooms to those in NFPA 72: 2010. The effective compliance date is Jan. 1, 2015.

The 2015 edition of NFPA 720 is expected to have identical provisions to those in NFPA 72: 2013, including the expansion of the requirements for tactile notification and the recommendations for audible low frequency and tactile notification for all occupants, regardless of the presence and magnitude of hearing loss. These provisions in NFPA 720 are intended to provide individuals the same protection from carbon monoxide (CO) hazards as NFPA 72 provides to these same individuals from smoke and fire.

Not every local jurisdiction has adopted the 2010 or 2013 version of NFPA 72, but an increasing number of jurisdictions have. Remember to follow manufacturer instructions, as well as your local building/code regulations, for the use and installation of any audible visible notification devices.

Overall, the takeaway is that each application must be evaluated on its own merits. Each application — hotel and motel guest rooms, dorms, and so on — requires a careful study to determine the suitability of systems to meet associated codes. It is not always one or the other; each application has its associated suitability versus code requirements.


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Article Topics
Fire/Life Safety · Carbon Monoxide · NFPA 72 · All Topics

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