horn strobe

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normbac

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I have wired alot of fire alarm systems for custom homes only. They have always been a 120 volt exterior bell hardwired to a water flow relay and to the breaker.
Inspector wants me to install interior horns on each floor and an exterior horn strobe on the house. Is this a low volt? how do you wire it to the flow valve ? etc; any input on how to do this type of setup would be apprecated, of course they need it tomorrow.
Also I read that an interior horn without a strobe is against ADA and NFPA standards is this true.
 
normbac said:
I have wired alot of fire alarm systems for custom homes only. They have always been a 120 volt exterior bell hardwired to a water flow relay and to the breaker.
Inspector wants me to install interior horns on each floor and an exterior horn strobe on the house. Is this a low volt? how do you wire it to the flow valve ? etc; any input on how to do this type of setup would be apprecated, of course they need it tomorrow.
Also I read that an interior horn without a strobe is against ADA and NFPA standards is this true.
Click to expand...

Do you mean water flow switch?
 
normbac said:
Is this a low volt? how do you wire it to the flow valve ?
Click to expand...
1. I imagine you can find them in either line- or low-voltage versions.

2. I would imagine just like any single-pole switch in line with a load.
 
I don't remember the exact wording of the code or the section but I believe the intent of the code is such that if there is water flowing frrom a sprinkler head that broke, a bell must ring. If you shut the water main shut-off the water will stop and so will the bell. By the same token, if you have the flow switch connected to a fire alarm system, that zone will not be silencable as long as water is flowing. You can try and reset the syatem but if there is still water flowing the alarm will re-sound.

Anyway, to try and answer your question, there should be two micro switches inside the flow switch. If local codes require you to connect 120 VAC through the N/O contacts of one of those switches to operate the bell, so be it. The other switch should be used to connect to the FA system. Frankly speaking, if you have a F/A system with battery back-up you'd be much better off using a LV bell run off the system. That way, in a power-fail condition, the bell would still ring. Along the same lines, if you are required to install horn-strobe units inside the house they should be LV and connected to the F/A system.

I wasn't aware that ADA requirements applied to residential installations but then again I've been out of that area of the trade for many years now. The horn-strobe on the outside of the house is so that the fire trucks wont have to look for house #'s when they're coming down the street concentrating on making as much noise as they can. They'll be able to see the light flashing.
 
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