# 520 Hz



## cda (Mar 12, 2014)

http://lifesafetymagazine.com/2013/09/bringing-nfpa-72-520-hz-into-focus/

How does the new 520 Hz requirement translate to your designs for these areas?

Anyone designing systems today really needs to pay attention to the current code requirements. Many people would argue that, for example, NFPA 72: 2013 is not enforced in any jurisdiction specifically yet, but it is the latest technological information we have available to us that we should be using for design. Sometimes that presents an issue with authorities having jurisdiction because it may require more or less than a previous code. Legally, you’d be advised to follow the most recent technical document available when conducting your work. We not only follow the latest editions of the code in our designs, but also take advantage of any new research that gives insight in order to provide more universal designs to our clients.


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## Rick18071 (Mar 12, 2014)

Is this in the 2012 IBC or IRC? Still on the 2006 here.


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## cda (Mar 12, 2014)

It is in NFPA 72 2013 edition.  18.4.5

And maybe 2010 edition

So your ahj would have had to adopt it

But supposedly after 1/1/2014 smoke alarms are suppose to meet the 520???


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## cda (Mar 12, 2014)

Ok after a little more research guess this shouild be under fire or building thread

So if you are enforcing NFPA 2010 or newer::::

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.

For single station smoke alarms “in sleeping areas only”

29.3.6    Audible fire alarm signals shall meet the performance requirements of 18.4.3 and 18.4.5.


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## cda (Mar 13, 2014)

Anyone requiring 520 hz a/v's. ??


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## cda (Mar 13, 2014)

Re-Thinking Fire Alarm Notification and Required Visual and Audio Alerts

New research and code requirements drive changes to audio and visible alerts.

By Joan Engebretson

August 1, 2013

 Security dealers will need to rethink their decisions about certain fire alarm notification appliances as the result of new code changes. Audio output devices are the ones primarily impacted by the code changes, but some requirements also impact visual outputs.

SOUNDERS FOR SLEEPING QUARTERS

The 2010 and 2013 versions of the National Fire Alarm and Signaling Code from the National Fire Protection Association, known as NFPA 72, have a new requirement for sleeping areas in new installations in commercial buildings that is scheduled to kick in Jan. 1, 2014, explains Lee Richardson, senior electrical engineer for the NFPA.

In those installations, dealers now will have to install low-frequency sounding devices that use 520 Hz square waveforms or produce an equivalent sound, explains Rodger Reiswig, director of industry relations for Westminster, Mass.-based fire systems integrator SimplexGrinnell. The new requirement was triggered by research conducted by the NFPA’s Fire Analysis and Research division, which determined that these lower-frequency sounders did a better job of waking people who are hearing or alcohol impaired than the higher-frequency sounders that have been used to date.

Not every local jurisdiction has adopted the 2010 or 2013 version of NFPA72. But the number of jurisdictions that have is on the rise — and more will be added moving forward.

To meet the new low-frequency requirements, manufacturers have had to rethink the piezoelectric sounders traditionally used with fire alarm systems, which typically operate in the range of 3000 Hz, explains Roopa Shortt, audio visual marketing manager for St. Charles, Ill.-based fire equipment manufacturer System Sensor. Shortt notes that System Sensor has developed a device that uses speaker technology rather than piezoelectric technology to produce a 520 Hz tone. Minimizing the size of the product was particularly challenging, she said, noting that a 520 Hz tone is similar to the sound put out by the large base speakers built into home stereo systems.

Reiswig notes another alternative to using sounders designed specifically to work at 520 Hz. As he explains, SimplexGrinnell uses a fire panel that has an amplifier and sound player that can send a signal to a speaker to enable it to produce the appropriate 520 Hz tone.

Another option, Richardson says, is to use an appliance that listens for the traditional fire alarm speaker tone and then outputs the appropriate low-frequency tone. He notes that some dealers may already have been using these devices to meet a requirement that is already in effect in some jurisdictions for residential installations.

As Richardson, explains, the 2010 and 2013 versions of NFPA72 require the use of the lower-frequency sounders in residential installations for quarters where people with hearing impairments are known to sleep. That requirement doesn’t share the January 2014 implementation date but instead takes effect as soon as a jurisdiction adopts either the 2010 or 2013 version of the standard.


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## cda (May 2, 2014)

Everything you wanted to know about 520

http://www.systemsensor.com/en-us/training/Pages/0514_IntroLowFrequency.aspx


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