Explanation of Fire Alarm Interface with Elevators
Notes:
There can be many variations of the accompanying "Pictorial Representation of Fire Alarm Interface
with Elevators".
In this example, the smoke and heat detectors are addressable initiating devices and the operating
relays are "hardwired".
To achieve supervision, the relay circuits are operated from NAC (Notification Appliance Circuits).
The supervisory initiating device which monitors shunt trip power is connected to a "hardwired" IDC
(Initiating Device Circuit).
The scenario assumes that:
1.
There is a sprinklered elevator hoistway.
2.
Means to disconnect the main line power to the elevator is via a shunt trip breaker.
3.
System operation is in accordance with NFPA 72 (1996).
4.
Relay (R5) and an IDC (Initiating Device Circuit) has been included to provide indication (via a
supervisory alarm) of absence of voltage (power) to operate shunt trip breaker. This potential
requirement is the TIA process.
Components
Function
R1
Signal to elevator controller for recall to designated level.
R2
Signal to elevator controller for recall to alternate level.
R3
Signal to elevator controller for firefighter notification (has not appeared yet in
Elevator Safety Code ANSI/ASME A17.1 - in process).
R4
Signal to activate shunt trip relay.
R5
Supervisory relay to monitor presence of voltage (power) to operate shunt trip
breaker.
NAC1
Notification Appliance Circuit for operating R1.
NAC2
Notification Appliance Circuit for operating R2.
NAC3
Notification Appliance Circuit for operating R3.
NAC4
Notification Appliance Circuit for operating R4.
IDC1
Initiating Device Circuit to supervise R5 contacts (monitoring power to operate shunt
trip breaker).
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