Fire Alarm Systems
Addressable Fire Alarm Control Panel employ one or more signalling Line Circuits - usually referred to as loops or SLC loops - ranging between one and thirty. Depending on the protocol used, a signalling line circuit can monitor and control several hundred devices.
Each device on an SLC has its own address, and so the panel knows the state of each individual device connected to it. Common addressable input (initiating) devices include
- Smoke detectors
- Heat detectors (Rate of Rise and Fixed Temperature)
- Manual call points or Manual pull stations
- Notification appliances
- Fire sprinkler system inputs
- Flow control
- Standard switches
- Monitor modules
Addressable output devices include
- (Warning System/Bell) relays
- Door holder relays
- Auxiliary (control function) relays
- Control modules
- Relay modules
Output devices are used to control a variety of functions such as
- Switching fans on or off
- Closing/opening doors
- Activating fire suppression systems
- Activating notification appliances
- Shutting down industrial equipment
- Recalling elevators to a safe exit floor
- Activating another fire alarm panel or communicator
Also known as "cause and effect", mapping is the process of activating outputs depending on which inputs have been activated. Traditionally, when an input device is activated, a certain output device (or relay) is activated. As time has progressed, more and more advanced techniques have become available, often with large variations in style between different companies.
Zones are usually made by dividing a building or area into different sections. Then depending on the specific zone, a certain number and type of device is added to the zone to perform its given job. Zones are a requirement by the National Building Code in Canada and zones must be labelled and include RED LEDs for fire zones, AMBER LEDs for supervisory and trouble. This is in addition to an LCD display although they relax this requirement if the LCD has 8 or more lines of characters. Isolators are also required when wiring departs a zone and enters a new zone such as floor to floor and between firewalls.
Groups contain multiple output devices such as relays. This allows a single input, such as a smoke detector or MCP, to have only one output programmed to a group, which then maps to multiple outputs or relays. This enables an installer to simplify programming by having many inputs map to the same outputs, and be able to change them all at once, and also allows mapping to more outputs than the programming space for a single detector/input allows.
This is the part of a fire panel that has the largest variation between different panels. It allows a panel to be programmed to implement fairly complex inputs. For instance, a panel could be programmed to notify the fire department only if more than one device has activated. It can also be used for staged evacuation procedures in conjunction with timers.