Smoke Detectors for Elevators

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steve66

steve66

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Location
Illinois
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Engineer
This isn't really a NEC question, but I'm betting a lot of you are familiar with fire alarm codes.

Is a smoke detector required in a elevator pit or at the top of the hoistway? There are no sprinklers in the elevator hoistway or anywhere around this elevator.

From NFPA 72, 3-9.3.4:
Smoke detectors shall not be installed in elevator hoistways.
Exception: Where the top of the elevator hoistway is protected by automatic sprinklers.
Exception: Where a smoke detector is installed to activate the elevator hoistway smoke relief equipment.
Click to expand...
That seems to say they are not only not required, but prohibited (unless there is a sprinkler or smoke relief). But I don't understand why they would be prohibited in the hoistway.
Steve
 
Re: Smoke Detectors for Elevators

Steve66, Usually in the pit you install a heat detector and at the top of the shaft another heat detector and in almost all cases a smoke goes at the top of the shaft.It is very unusual that a sprinkler system is not present,because it is off of the sprinkler head that you measure for the location of the F.A. devices? The heats are for activating yuor shunt trip breaker.I'm guessing that this is why they are prohibited if a sprinkler system is not present,because they have to insure that the elevator will function as intended during a fire [i.e.] recall system. This sounds like an older elevator that is getting upgraded,I would hope that the sprinkler is part of it. good luck.
 
Re: Smoke Detectors for Elevators

benaround at least in this area the shunt trips are being disconnected.

From what I was told the code has been changed.

We still do heats in the shaft that trip the FACP.
 
Re: Smoke Detectors for Elevators

Steve, I think you will find your answer in ANSI 17.1(A) or ASME 17.1?

It is becoming the norm for sprinklers not to be installed in shafts in N.C. (especially state jobs) which simplifies the installation as far Benarounds mention of the shaft devices and the associated shunt trip breaker.

The elevator still must have primary and secondary recalls.

Roger
 
Re: Smoke Detectors for Elevators

Iwire, Thanks for the heads up, Regrettably I live in Arizona now and they are so far behind the rest of the world it's not even funny.Case in point, recently the city of Mesa adopted the 1993 N.E.C. this is not a typo 1993. Take care.
 
Re: Smoke Detectors for Elevators

No problem but remember I got this info about the code change second hand.

I do know for fact that a coworker had to disconnect the shunts at a few locations per order of the elevator inspector, this was in RI.

Bob
 
Re: Smoke Detectors for Elevators

I was told that this is because maintentance and testing can be difficult in the hoistway, as well as possible misapplication. Also, in the latest NFPA 72, the requirement for the shunt trip got changed to include a time delay after the heat trips. This is to ensure that the elevator has returned before power is cut off, but they don't list the time. If you realize that there is no circuit coordination between the smoke which is to return the cab and the thermal which cuts power, you probably want to take the stairs! When required, I list the older type of mechanical thermals which react slower than the newer addressable electronic types, or worse, rate of rise.
 
Re: Smoke Detectors for Elevators

Thanks for the replies. It sounds like the smoke detector isn't required. ASME is one of the few codes we don't have.

Benaround: It is a new elevator installed in an older building with no sprinkler system (at least in the part of the building the elevator is in.)

Steve
 
Re: Smoke Detectors for Elevators

I understand that the downside of the smoke detector in the shaft is due to the dust being pulled up and down the shaft, causing the smoke detector to become dirty/fouled quickly. This leads to the maintenance issue that NVCAPE mentioned.
-Claus
 
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