Audibility in correctional facilities?

[fapa]

This is new to me but I'm having a hard time finding exceptions to audibility as part of the Canadian code. I know for example prison cells don't have fire alarm speakers or horns, but I cannot understand why when looking through NBC and all related codes. Is it simply because we have speakers outside the cells and that will provide us with required audibility? Or is there another reason (i.e they cannot leave anyway).

I see NFPA 72 seems to have exceptions (private operating mode) but my review of NBC and CAN/ULC doesn't seem to reference NFPA 72 as it relates to those sections. So not sure if I can really pick and choose from there?

 

[tmurray]

The code requires fire alarm signals to be audible throughout the floor area. This allows the horns to be places anywhere in the suite, provided audibility is met.

Individual cells are not suites, so they don't need dedicated fire and life safety systems.

Where NFPA 72 is not referenced in the Canadian codes, you would need to develop an alternate solution to permit it to be used instead of ULC-S524.

 

[Ask Bing Code]

This is new to me but I'm having a hard time finding exceptions to audibility as part of the Canadian code. I know for example prison cells don't have fire alarm speakers or horns, but I cannot understand why when looking through NBC and all related codes. Is it simply because we have speakers outside the cells and that will provide us with required audibility? Or is there another reason (i.e they cannot leave anyway).

I see NFPA 72 seems to have exceptions (private operating mode) but my review of NBC and CAN/ULC doesn't seem to reference NFPA 72 as it relates to those sections. So not sure if I can really pick and choose from there?

What you saw might not comply with the Code, if you can't find exceptions in the Code.

 

[Inspector Gadget]

This is new to me but I'm having a hard time finding exceptions to audibility as part of the Canadian code. I know for example prison cells don't have fire alarm speakers or horns, but I cannot understand why when looking through NBC and all related codes. Is it simply because we have speakers outside the cells and that will provide us with required audibility? Or is there another reason (i.e they cannot leave anyway).

To concur with Tmurray, 3.2.4.18(1)(a) requires alarms to be audible throughout the floor area, with a sound pressure of at least 65dba [3.2.4.18(6).] How that audibility is obtained is largely irrelevant: speakers, horns, piezoelectric devices: all are essentially electrical components creating sound pressure, and as long as it's loud enough, and has the right pattern [3.2.4.18(2)] that's all that counts. Audibility of alarms is one of the elements documented in an S1001 (life-safety commissioning) report.

The only thing that might be in the area of what you're looking for are the requirements for visual alerts in loud areas (factories, concert halls - see 3.2.4.19) but these visual signals are in addition to audible signals.

 

[fapa]

Thank you all for the various perspectives.

What you saw might not comply with the Code, if you can't find exceptions in the Code.

To concur with Tmurray, 3.2.4.18(1)(a) requires alarms to be audible throughout the floor area, with a sound pressure of at least 65dba [3.2.4.18(6).] How that audibility is obtained is largely irrelevant: speakers, horns, piezoelectric devices: all are essentially electrical components creating sound pressure, and as long as it's loud enough, and has the right pattern [3.2.4.18(2)] that's all that counts. Audibility of alarms is one of the elements documented in an S1001 (life-safety commissioning) report.

The only thing that might be in the area of what you're looking for are the requirements for visual alerts in loud areas (factories, concert halls - see 3.2.4.19) but these visual signals are in addition to audible signals.

That's what I kept concluding but couldn't explain why they weren't present in the cells themselves (as per a very recent fire alarm design I came across. But see my possible explanation below). Code does say "throughout the floor area" with only exception for stage 1 alert signal when it comes to "continually staffed" locations.

The code requires fire alarm signals to be audible throughout the floor area. This allows the horns to be places anywhere in the suite, provided audibility is met.

Individual cells are not suites, so they don't need dedicated fire and life safety systems.

Where NFPA 72 is not referenced in the Canadian codes, you would need to develop an alternate solution to permit it to be used instead of ULC-S524.

In the design I'm referencing they did have, what they note as, "loudspeakers" outside the cells. So my only thought is that audibility will be fine since, my guess, they test with the doors open. The code only specifies sound levels of sleeping rooms in "residential occupancy". Perhaps this is how they achieve this, as per your comment.

It does seem strange though there's no exception on the Canadian side. Prisoners can't leave on their own anyway, so not clear why audibility is necessary for a room with restricted exiting.