I'm designing a new fire alarm system for a high rise student dormitory. Code requires that this building have an automatic fire detection system as well as voice evacuation. Here's the issue: the campus likes to use bell/strobe devices instead of horn/strobes. Typically I would install a combination speaker/horn/strobe device but with a bell/strobe I would have to install a seperate speaker for the system. To me this makes no sense as the bell would have to be interupted so the voice evacuation announcement could be heard. Has anyone done anything like this? Any input would be greatly appreciated. Thanks.
High Rise Fire Alarm System
- Thread starter bfletcher
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- New York, 40.7514,-73.9925
I haven't used bells in a long time.
I would think you need to talk with the AHJ.
Bells don't work even if voice evac wasn't required, as code requires temporal pattern signals.
I would think you need to talk with the AHJ.
Bells don't work even if voice evac wasn't required, as code requires temporal pattern signals.
Try specifying a tone generator with the fire alarm system speakers. A bell "sound" can be rung in addition to the voice alerts, thus negating the need for bells.
Yet, wondering if the school understands that the bell circuit would be turned off under alarm conditions (real bells or electronic tones)? The floor voice speakers govern in high rise conditions.
And, would also suggest considering how a mass notification system is employed, there can be some sharing of systems in most cases
Yet, wondering if the school understands that the bell circuit would be turned off under alarm conditions (real bells or electronic tones)? The floor voice speakers govern in high rise conditions.
And, would also suggest considering how a mass notification system is employed, there can be some sharing of systems in most cases
I agree with all of this. I don't think a bell/speaker system would be code compliant as the audible signal has to be clear, unique, and indistinguishable from other signals. With the voice speaker system the bell sound can be programmed - if allowed by the AHJ.
I still think the temporal pattern would be much better - especially when you have to do a voice announcement also, but I just ran across this in NFPA 72. There is an exception that allows the AHJ to permit the continued use of an existing "evacuation" signal. It's 6.8.6.5 in the 2007 edition of NFPA 72.
But in this situation does that apply? An "existing" signal may only be for an existing building, not necessarily the campus.
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