# Low frequency Audio for sleeping area



## cda (Jun 27, 2017)

For a full fire alarm system, where you have sleeping areas.

Low Frequency sounders are required in the sleeping areas.

NFPA 72:

18.4.5.3 * 


Audible appliances provided for the sleeping areas to awaken occupants 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 waveform shall have a fundamental frequency of 520 Hz ± 10 percent.


(3)*
The notification equipment shall be listed for producing the low frequency waveform.


SO, recently have had a few fire alarm contractors interpret that to mean, besides each bedroom, the living room area also requires a low frequency sounder. I could almost agree with that, when I walk into some apartments and there is a full size bed in the living room.

Or, a so called Den/Office.


Anyone requiring low frequency anywhere besides actual labeled bedrooms???


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## Francis Vineyard (Jun 27, 2017)

This was clarified in NFPA 72: 2013, the Chapter 18 text was slightly changed to clarify that the low frequency requirements were intended to “awaken” people who are sleeping only.


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## cda (Jun 27, 2017)

Francis Vineyard said:


> This was clarified in NFPA 72: 2013, the Chapter 18 text was slightly changed to clarify that the low frequency requirements were intended to “awaken” people who are sleeping only.




Will have to look at that, I think I quoted 2016?

So yea or nea in the living room


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## Francis Vineyard (Jun 27, 2017)

Sleeping areas (and hotel guest rooms) designated on the drawings. Not in hallways and corridors as with smoke alarms.


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## Rick18071 (Jun 27, 2017)

I'm spending the weekend on my own dam couch! May take a nap or two too.


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## cda (Jun 27, 2017)

Francis Vineyard said:


> Sleeping areas (and hotel guest rooms) designated on the drawings. Not in hallways and corridors as with smoke alarms.




Undersstand that, but say an embassy suite unit

They have a separate bedroom,,,

But also have a fold out couch in the seperate "living room"


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## Francis Vineyard (Jun 27, 2017)

What if's are not in the code


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## cda (Jun 27, 2017)

Francis Vineyard said:


> What if's are not in the code




It is not a what if

Just seeing how that section of 72 is being applied


Just because it does not say bedroom, but has a fold out couch, does that than make it a sleeping area?


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## mtlogcabin (Jun 27, 2017)

cda said:


> Undersstand that, but say an embassy suite unit
> 
> They have a separate bedroom,,,
> 
> But also have a fold out couch in the seperate "living room"



Yes both rooms. If it has furniture to sleep that converts to a bed then it is a sleeping room.
most restrictive codes apply to multi use facilities/rooms


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## linnrg (Jun 27, 2017)

what is the source of the new device requirements - manufacturers creating better products or is this coming from the disability angle?


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## cda (Jun 27, 2017)

Supposedly you can hear them better in your sleep

It started being a NFPA 72 requirement in 2014


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## cda (Jun 27, 2017)

*What is the new low frequency sounder requirement?*

NFPA 72 has initiated a code change to the 2010 edition that will require that certain new sleeping areas utilize a low frequency sounder with a 520 Hz (+/- 10%) square wave. This new requirement is located in Section 18.4.5: Sleeping Area Requirements.

*Will this requirement also be in effect in the 2013 edition of NFPA 72?*

Yes, the requirements are still in effect in the 2013 edition of NFPA 72.

*When is the compliance date for low frequency sounder installations?*

January 1, 2014

*Why has this code change been implemented?*

The intent of this low frequency tone is to accommodate occupants in sleeping rooms with mild to severe hearing loss. This new requirement is based on a series of research studies funded by NFPA that concluded that a low frequency tone, around 520 Hz, is more effective at waking sleeping individuals, including those with mild-to-severe hearing loss.




https://www.systemsensorblog.com/20...-20102013-low-frequency-sounder-requirements/


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## mtlogcabin (Jun 28, 2017)

Low Frequency Tone

A study conducted by researchers from Victoria University in Australia released in May 2006 tested numerous auditory signals and alternative alarms. The goal of the study, which was sponsored by the Fire Protection Research Foundation, was to determine which were most successful at waking and alerting individuals with partial hearing loss during an emergency. The research found that a lower frequency tone was much more effective than the 3,100 Hz higher frequency tone commonly used in smoke alarms and audible notification appliances (horns).

Audible emergency evacuation signals set at a 520 Hz square wave tone awakened 92 percent of the hard-of-hearing test participants when used at or below the code-minimum sound level of 75 decibels for 30 seconds. A square wave is different from a pure tone signal in that a square wave consists of a specific fundamental frequency and an infinite number of subsequent peaks at odd-numbered harmonics.

The success rate was 100 percent for the 520 Hz square wave tone at 95 decibels. On the other hand, one study found that only 57 percent of hard-of-hearing individuals awoke to a 3,100 Hz signal up to 75 decibels.

Even though there are as many as 70 million Americans with high-frequency hearing loss, all can benefit from having alarms with low-frequency pitches. Statistics show that senior citizens are not as likely to awaken to a traditional smoke alarm. According to the Topical Fire Report Series of 2004, adults ages 64-plus represented 12 percent of the U.S. population, yet accounted for more than 30 percent of all fire deaths.

Most children, deep sleepers, alcohol-impaired individuals, and people taking sleeping medications are also less likely to wake up when a smoke or CO alarm sounds. The research also showed that the low-frequency signal was 63 to 69 percent more effective at waking children, heavy sleepers and people with hearing loss than current high-pitched alarms, demonstrating the effectiveness of the lower frequency 520 Hz square wave signal in arousing sleepers in all these instances.


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## IJHumberson (Jun 29, 2017)

We've been requiring the low frequency audible appliances in sleeping rooms. While we don't require them in the Living Room or main living areas, we do have an amendment that reads thus: "Enclosed rooms such as dens, libraries, studies, or sitting rooms which could be used as a temporary sleeping area shall be treated as bedrooms."


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