What Makes Interfacing the Fire Alarm to Elevator Capture Difficult?
Fire alarm installers and elevator mechanics use the same words, but the words have different meanings. When interfacing the fire alarm system and the elevator controls, it helps to take the time to understand each other's needs.
To capture an elevator, usually smoke is detected by smoke detectors and they are controlled by a Fire Alarm System. The Elevator has its own controls. The systems have to work together, however interfacing the two together is where problems sometimes exist.
By Douglas Krantz
People are afraid of fire. They also know that where there's smoke, sometimes there's fire. That's why they don't want the elevator to stop and let them out on a floor where there's smoke.
Purpose of Elevator Capture
In order to protect an elevator's passengers, the elevator is captured when smoke is detected; when there's smoke in an elevator lobby, the elevator will stop what it's doing
and let any passengers out on a floor where there's no smoke.
In order to let the passengers escape the building, the elevator will usually be captured to the primary floor. However, if that's where the smoke is detected, to allow the passengers to get out of the building by a different route, the elevator will be captured to the alternate floor.
Installation of Elevator Smoke Capture
The installation of the elevator smoke capture system is often a cooperative venture between the elevator company's capture system and the fire alarm installer's smoke detection system.
The elevator company installs and upgrades the elevators. By itself, this part of the capture system usually works correctly.
Whether it's a stand-alone elevator smoke detection system, or the elevator smoke detection system is part of a building's common area wide fire alarm system
, it's the fire alarm company that usually installs and upgrades the elevator's smoke detection system. By itself, this part of the detection system usually works correctly.
However, even if the elevator is programmed correctly for capture, and the smoke detection system is programmed correctly, commonly problems arise in the wires between the two systems.
Code Regulation Language
Most of the problems come from the different language used between the elevator code book and the fire alarm code book. Even though both systems use the common language of the country, the industry speak of each system is different because the point of view of each system is different.
It's location versus function
The elevator regulation talks about the location of the smoke detectors:
- The smoke detector on the primary floor
- The smoke detectors on all the other floors
- The smoke detector in the mechanical room
The fire alarm regulation talks about the function of the smoke detectors:
- The smoke detector that sends the elevator to the alternate floor
- The smoke detectors that send the elevator to the primary floor
- The smoke detector that captures the elevator and at the same time signals smoke in the mechanical room
Interface Wire Labels
Because of these different languages, the labels between the systems have to be different on the ends of each wire.
Fire Alarm End of the wire says:
Sends to Primary Floor
Sends to Alternate Floor
Elevator Mechanical Room
Elevator Controller End of wire says:
All Other Smokes
Primary Floor Smoke
Elevator Mechanical Room
Smoke Detection and Elevator Interface
When these languages are understood, the interface between the smoke detection system and the elevator controller becomes easy, and when it's captured, the elevator will go to the correct designated floor.
Based on his electronics training, and his understanding of Life Safety, Douglas Krantz has compiled his knowledge of Conventional Fire Alarm Systems into the book Make It Work - Conventional Fire Alarms
. The book covers the basics of the Conventional Fire Alarm System, and shows how Life Safety and internal supervision affects the fire alarm system.
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