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Fire Alarm -- Installation

Elevator Capture is a joint venture between the elevator installers and the fire alarm installers. The interface between the two is where problems sometimes exist.
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.
Douglas Krantz -- Fire Alarm Engineering Technician, Electronic Designer, Electronic Technician, Writer






What Makes Interfacing the Fire Alarm to Elevator Capture Difficult?

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.






PDF Book PDF of Make It Work - Conventional Fire Alarm Systems


Douglas Krantz

Describing How It Works
facpdoug@douglaskrantz.com

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Electrical Flow


On this website, most references to electrical flow are to the movement of electrons.

Here, electron movement is generally used because it is the electrons that are actually moving. To explain the effects of magnetic forces, the movement of electrons is best.

Conventional current flow, positive charges that appear to be moving in the circuit, will be specified when it is used. The positive electrical forces are not actually moving -- as the electrons are coming and going on an atom, the electrical forces are just loosing or gaining strength. The forces appear to be moving from one atom to the next, but the percieved movement is actually just a result of electron movement. This perceived movement is traveling at a consistent speed, usually around two-thirds the speed of light. To explain the effects of electrostatic forces, the movement of positive charges (conventional current) is best.

See the explanation on which way electricity flows at www.douglaskrantz.com/
ElecElectricalFlow.html
.