SLC – Signal line circuits are initiating devices in an addressable fire alarm system. Notification devices notify in-building occupants about a problem. This is done by audible, visible, tactile, and textual devices. Fire alarm systems can be put into three system designs.
What are SLC circuits used for?
Signaling Line Circuit (SLC)
The Signaling Line Circuit or SLC in a fire alarm system is a power and computer style data bus. It is used to provide power to the computers inside each module and detector (each device), carry information from the panel to the devices, and carry information from each device to the panel.
What is SLC and NAC?
NFPA 72 identifies three separate types of fire alarm system signaling paths: initiating device circuits (IDC), signaling line circuits (SLC), and notification appliance circuits (NAC). … In it, an SLC is defined first by stating that it is a circuit capable of supporting any mixture of addressable devices.
What is NAC fault in fire alarm system?
An Open NAC is a trouble on a fire alarm panel that shows that a wire in the building, somewhere along the Notification Appliance Circuit, or horn / strobe circuit, has has broken wire or it has come loose from a screw terminal or splice.
What is Class A and Class B wiring?
If a connection or wire is broken, Class B Wiring Systems stop working properly. … Class A Wiring Systems go a step further. Not only do they indicate there is trouble in the wiring, but if a fire breaks out in the building, before a single broken wire or connection has been fixed, all devices will still work.
What is a NAC fire panel?
NAC: Short for “Notification Appliance Circuit“. Also called the Bell Circuit, Signal Circuit, or Output Circuit. OUTPUT DEVICES are terminated to the NAC in either a Class “A” or Class “B” configuration.
What is NAC cable?
The Notification Appliance Circuit is a pair of wires that carry power from the control panel to the devcies that warn people of danger: the horns, strobes, bells, speakers, chimes, etc. … The wires that make up the circuit are what are being supervised. NAC is the acronym for Notification Appliance Circuit.
What is a protection loop short?
A Protection Loop Short indicates that you might have some faulty wiring for a particular zone or a faulty alarm panel. This wiring or alarm panel fault requires a technician to attend and check the system. If the signal persists, please call during business hours to arrange a technician.
What is a fire alarm loop?
Loop. Addressable fire alarm panels have one or more loops used to connect devices to the panel. The single wire connection leaves and returns to the panel in a complete loop.
What are the 2 types of fire alarms?
Generally, there are two types of home smoke alarms: photoelectric and ionization.
What is a P1 fire door?
P1 protects the whole building, P2 is installed in defined parts of the building only. The objective of a category P is to provide the earliest warning of a fire to minimise the time taken from ignition of a fire to detection and the subsequent attendance by the fire services, minimising loss to the property.
How much area does a smoke detector cover?
In compliance with the National Fire Protection Association (NFPA), smoke alarms will cover a radius of 21 feet, and an area of coverage of 1,385 square feet. The maximum distance between two smoke alarms should be 30 feet.