ECN Forum Forums General Topics of the Trade General Discussion Area Fire Alarm Q.

I have some fire alarm experience but I never worked on one with an elevator in the building.

What is "elevator recall," and how does it work?


Thanks,
Peter

Peter,

Elevator recall returns the car, normally to the lobby, so that it cannot be used by the occupants. It also is now available for the fire department. They should have a key to override the controls.

Hi Peter. I do not know if it is the same everywhere but for this area elevator recall works like this.

A smoke detector is installed in front of every elevator door. When one of these smoke detectors trips it sends a signal to the elevator control system.

We provide two signals Primary and Secondary.

Primary and secondary floors are chosen, typical the primary floor is the floor with easiest exit from the building.

If the primary floor is floor one, any smoke detector tripping on another floor sends the car to floor one.

If the smoke detector on floor one trips the elevator is sent to the secondary floor.

Once smoke is detected the cars make one trip to the assigned floor and park on that floor with the doors wide open.

The elevator is now unusable to all but the FD with the use of their key.

The idea is not to send people to the fire floor.



[This message has been edited by iwire (edited 10-13-2004).]

Also keep in mind that if there is a sprinkler system in the elevator shaft you will have to provide heat detection to activate an automatic power disconnect.

Ron in RI we have been instructed by elevator inspectors to disconnect the shunts for automatic power disconnect.

I believe the reason was to keep firefighters from being trapped if they are using the car after recall trips.

I do not know if the rules have changed.

Bob

Heat detectors in the elevator machine room are used to shunt power to elevator equipment as well.

The shunt trip or rather automatic disconnecting means comes from sprinkler requirements for elevator hoistways and machine rooms - ANSI/ASME A17.1 and is referred to in NFPA 72

NFPA 72 just tells us if you are going to do this here is how it will be done. Elevator inspectors in the Denver area have differing opinions as well and I have never seen a fire inspector over ride the elevator inspectors decision.

In one case I had to install two heat detectors in the shaft and machine room that tripped at two different heat levels. The lower temp detector fired a warning horn in the cab to warn the fire fighters of a fire in the shaft or machine room and the second one tripped the power to the equipment.

Edit to add that this system was to give the fire fighters time to get out of the car.



[This message has been edited by kentvw (edited 10-14-2004).]