Addressable Fire Alarm System
The elevators are "captured" by the smoke detectors in the elevator lobbies, the elevator machine room, and sometimes even the hoistways. No other fire alarm device in the building can be used for the capture of the elevators. Also, the control panel that controls the smoke-capture of the elevators has to show the specific detector that sensed smoke.
In addition, some detectors have to be used to send the elevator to the primary egress floor of the elevator, some have to send the elevator to an alternate egress floor, and some smoke detectors have to turn on a warning fire-hat light for the firefighters. In essence, at least three different, dedicated, relay outputs are needed for the elevator capture system.
If there are any sprinkler heads in the elevator machine room or in the elevator hoistways, there has to one heat detector, within 2 feet (about 2/3 meters) of each sprinkler head. If there are four sprinkler heads in a large elevator machine room, that means there will be four heat detectors.
The purpose of these heat detectors is to shunt (turn off) the elevators. This action prevents the elevator car's loss of control when the sprinklers spray water everywhere.
The shunt power also has to be supervised in case someone accidentally turns off the circuit breaker that provides the shunt power.
Addressable System Required
For practical purposes, the elevator capture smoke detection system has to be addressable. Most conventional fire alarm systems do not have a lot of output relays, so they are not capable of being used for elevator capture.
On-Site Control Panels
On top of everything else, the smoke detectors have to latch-in-alarm when they detect smoke. The easy way is to have the ability to reset the detectors is to have the reset button in the same building as the elevator.
If the reset for the latched-in-alarm smoke detector is in a separate building, just the location of the reset button is a huge liability issue that should be avoided at all costs. To keep the system simple, the control panel for the elevator smoke capture has to be on-site.
Two Systems per Building
Two Systems per Building
For practical reasons, there have been instances where the conventional fire alarm system isn't replaced, However, a second addressable fire alarm system is also installed for the elevator capture.
Yes, installing a second fire alarm system in a building is possible, but the fire marshal and the elevator inspector have to both agree to doing that.