Low Frequency Smoke Alarms

[JoeStillman]

IBC now requires 520 Hz audible alarms in R1 and R2 sleeping areas. Has anybody found a single-station/multiple-station combo smoke/CO alarm that meets that requirement? I tried to google it and came up with nothing. I have several projects on the boards right now that will have to comply with this and I'd prefer not to do it with system-type detectors and sounder bases.

 

[ptonsparky]

I can't help you, but I do believe even I can hear that range. High frequencies are lost to me.

 

[gadfly56]

IBC now requires 520 Hz audible alarms in R1 and R2 sleeping areas. Has anybody found a single-station/multiple-station combo smoke/CO alarm that meets that requirement? I tried to google it and came up with nothing. I have several projects on the boards right now that will have to comply with this and I'd prefer not to do it with system-type detectors and sounder bases.

If this is an IBC covered project (commercial/industrial), you are probably out of luck. If this is residential, you should be looking into the IRC for guidance. The New Jersey edition of the IRC does not mention 520 Hz sounders. The problem is that you need actual speakers to generate the 520 Hz tone, and these just will not run on batteries as they are such power hogs.

 

[gadfly56]

I can't help you, but I do believe even I can hear that range. High frequencies are lost to me.

According to an Australian study, the tone is effective for rousing those drunk or high. I forebear from asking.

 

[ptonsparky]

According to an Australian study, the tone is effective for rousing those drunk or high. I forebear from asking.

Unfortunately, not that much fun involved.

 

[RumRunner]

IBC now requires 520 Hz audible alarms in R1 and R2 sleeping areas.

Has anybody found a single-station/multiple-station combo smoke/CO alarm that meets that requirement? I tried to google it and came up with nothing. I have several projects on the boards right now that will have to comply with this and I'd prefer not to do it with system-type detectors and sounder bases.

At this frequency range, it falls under the Ultra Low Frequency. Spectrum.
Also known as INFRASOUND.
I’d be interested on that IBC requirement with details in regard to this mandate. Can you cite the website that says so?
This frequency can make people sick. It is a frequency range that humans cannot hear.

It gives people headaches but elephants can hear it.

Used in military extensively as well as rescue operation.

Is it perhaps a typo?

Perhaps you mean 520 KHz or 520 MHz.

“Ultra low frequency (ULF)

Ultra low frequency is the ITU designation for the frequency range of electromagnetic waves between 300 hertz and 3 kilohertz, corresponding to wavelengths between 1,000 to 100 km. In magnetosphere science and seismology, alternative definitions are usually given, including ranges from 1 mHz to 100 Hz, 1 mHz to 1 Hz, and 10 mHz to 10 Hz.Wikipedia”

Here is an account of its effect to humans.

https://www.pyroenergen.com/articles09/infrasound-effects.htm

 

[mtnelect]

This might help explain the NFPA requirement.

 

[hbiss]

At this frequency range, it falls under the Ultra Low Frequency. Spectrum.
Also known as INFRASOUND.
I’d be interested on that IBC requirement with details in regard to this mandate. Can you cite the website that says so?
This frequency can make people sick. It is a frequency range that humans cannot hear.

Ummm, we are talking about audio here, not RF. You most certainly can hear 520Hz and you do every day as part of music and noise. Normal humans with good hearing can hear from 20Hz all the way up to 20KHz. The hum from transformers is 60Hz. Can you hear that?

-Hal

 

[synchro]

Ummm, we are talking about audio here, not RF. You most certainly can hear 520Hz and you do every day as part of music and noise. Normal humans with good hearing can hear from 20Hz all the way up to 20KHz. The hum from transformers is 60Hz. Can you hear that?

-Hal

Agree.
The note C that's one octave above
middle C is 523 Hz.

 

[RumRunner]

Ummm, we are talking about audio here, not RF. You most certainly can hear 520Hz and you do every day as part of music and noise. Normal humans with good hearing can hear from 20Hz all the way up to 20KHz. The hum from transformers is 60Hz. Can you hear that?

-Hal

The way to ROUSE someone from asleep for example is by producing sound. What other (effective way ) to wake up someone?

Shake him perhaps or douse him/her with cold water?
Audio is sound, and the way to transmit sound is by decoding the information either analog or digital and you send it to a device that you use to control that sound.
The transmitter decodes it into a transferrable format and then sends it thru the radio waves.. . . through the frequency suited for human hearing.
In this example the transmitting and receiving processes are built into one single unit
The transmitter produces the frequency itself and fed to an amplifier to produce the sound.

You cannot separate the two (RF and sound) You can’t transmit sound without the frequency you’ve selected to transmit it.

The sound rides on the frequency . . . the sound is the rider.

 

[hbiss]

You cannot separate the two (RF and sound)

I suppose you could consider the 520Hz audio AC signal that's fed to the speaker RF. Indeed, you can pick it up with suitable amplification (like a wire tracer probe) some distance from the cable. But calling it RF isn't usual unless it is generated and fed to tuned antenna with a considerable amount of power. Else it isn't going to go anywhere without wire and that's the definition or purpose of RF.

-Hal

 

[winnie]

Electromagnetic waves (radio, light, etc.) are periodic variations in electric and magnetic fields.

Sound waves are periodic variations in pressure in a medium.

Humans cannot sense electromagnetic waves of 520 Hz. Humans can easily sense sound waves of 520 Hz.

Humans can easily sense electromagnetic waves of 520 THz, as yellow light.

Jon

 

[mopowr steve]

I just had a service call for an elderly lady that had a problem with a light not working in one of her rooms. Wound up just being a on/off switch turned off on a wall paddle fan control she didn’t realize.
As I am talking with her a notice a series of beeps coming from somewhere, I asked what it was and she says she doesn’t hear anything. Well, I find it to be a carbon monoxide alarm chirping like a low battery. I have it in my hand right in front of her and it chirps 3 times. I ask if she heard that and she said no.
I proceed over to her piano and rattle a few notes around middle c and she says she hears that but when I go to the highest octave she did not hear those notes. So I hit the test button on the smoke alarm again she does not hear it.
So, now I’m thinking NFPA should come up with something with varying frequencies so people with hearing loss (which usually starts out with certain frequency ranges) aren’t left with smoke detectors they can’t even hear.

 

[gadfly56]

I just had a service call for an elderly lady that had a problem with a light not working in one of her rooms. Wound up just being a on/off switch turned off on a wall paddle fan control she didn’t realize.
As I am talking with her a notice a series of beeps coming from somewhere, I asked what it was and she says she doesn’t hear anything. Well, I find it to be a carbon monoxide alarm chirping like a low battery. I have it in my hand right in front of her and it chirps 3 times. I ask if she heard that and she said no.
I proceed over to her piano and rattle a few notes around middle c and she says she hears that but when I go to the highest octave she did not hear those notes. So I hit the test button on the smoke alarm again she does not hear it.
So, now I’m thinking NFPA should come up with something with varying frequencies so people with hearing loss (which usually starts out with certain frequency ranges) aren’t left with smoke detectors they can’t even hear.

This is why they make bed shakers and visual alarms. A simple single station smoke alarm has a very hard time carrying this burden. Supposedly there are 520 Hz single station alarms out there, but they cost ~$200.

 

[mopowr steve]

This is why they make bed shakers and visual alarms. A simple single station smoke alarm has a very hard time carrying this burden. Supposedly there are 520 Hz single station alarms out there, but they cost ~$200.

That’s great when someone knows that they have hearing loss or are completely deaf. but what about those like this that didn’t even know that they were completely deaf to the loud screeching frequency of their smoke alarms.
Such a sad state of affairs should a fire break out and never be waken by your smoke detectors.

 

[winnie]

I have a couple of 'first alert' battery operated alarms which play a voice alert, saying to evacuate. If you hit the right button sequence on first power up it will even identify the location.

 

[ptonsparky]

I just had a service call for an elderly lady that had a problem with a light not working in one of her rooms. Wound up just being a on/off switch turned off on a wall paddle fan control she didn’t realize.
As I am talking with her a notice a series of beeps coming from somewhere, I asked what it was and she says she doesn’t hear anything. Well, I find it to be a carbon monoxide alarm chirping like a low battery. I have it in my hand right in front of her and it chirps 3 times. I ask if she heard that and she said no.
I proceed over to her piano and rattle a few notes around middle c and she says she hears that but when I go to the highest octave she did not hear those notes. So I hit the test button on the smoke alarm again she does not hear it.
So, now I’m thinking NFPA should come up with something with varying frequencies so people with hearing loss (which usually starts out with certain frequency ranges) aren’t left with smoke detectors they can’t even hear.

Yup. MDSW would have to shake me.

 

[hbiss]

I have a couple of 'first alert' battery operated alarms which play a voice alert,

Kidde has them also. While not perfect, I think that in combination with the beep it's better than the beep alone. Probably a good idea to make them mandatory since they cost little or nothing more.

-Hal

 

[mtnelect]

• Smoke alarms should be replaced 10 years from the date of manufacture. Combo smoke/CO alarms should be replaced after 5-7 years (depending on the model).

 

[ggunn]

You cannot separate the two (RF and sound) You can’t transmit sound without the frequency you’ve selected to transmit it.

Of course you can. RF waves and sound waves are completely different effects. Sound waves riding on RF are modulation effects and have to be decoded by electronic receivers and transducers to become audible. You can't hear RF no matter what the frequency, and any frequency sound can be carried on any frequency RF. The RF frequency may need to be the higher of the two. but I am not an RF modulation expert.