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Smoke detector mounted on a ceiling. A smoke detector is a device that senses smoke, typically as an indicator of fire.Smoke detectors/alarms are usually housed in plastic enclosures, typically shaped like a disk about 125 millimetres (5 in) in diameter and 25 millimetres (1 in) thick, but shape and size vary.
In the 2000’s, System Sensor introduced the i3 line of smoke detectors, which came in 2 and 4 wire models. These devices have a feature which they will poll with the fire alarm panel when the sensor is dirty, causing a trouble condition on the panel.
An aspirating smoke detector (ASD) is a system used in active fire protection, consisting of a central detection unit which draws air through a network of pipes to detect smoke. [1] The sampling chamber is based on a nephelometer that detects the presence of smoke particles suspended in air by detecting the light scattered by them in the chamber.
Combined sensing: While a standard smoke detector only senses smoke, one with combined sensing can detect both smoke and heat. "This feature detects various types of fires, such as those caused by ...
The prealarm LED is lit when one device has tripped. The prealarm LED may also be used if an addressable smoke detector registers low levels of smoke in the detection chamber, but not enough to trigger a full alarm. [3] Depending on the system's layout, the Notification Appliance Circuit (NAC) may or may not activate for prealarm conditions.
Fire alarm systems are required in most commercial buildings. They may include smoke detectors, heat detectors, and manual fire alarm activation devices (pull stations). All components of a fire alarm system are connected to a fire alarm control panel. Fire alarm control panels are usually found in an electrical or panel room.
An optical beam smoke detector is a device that uses a projected beam of light to detect smoke across large areas, [1] typically as an indicator of fire. [2] They are used to detect fires in buildings where standard point smoke detectors would either be uneconomical [ 3 ] or restricted for use by the height of the building.
The HART Communication Protocol (Highway Addressable Remote Transducer) is a hybrid analog+digital industrial automation open protocol. Its most notable advantage is that it can communicate over legacy 4–20 mA analog instrumentation current loops, sharing the pair of wires used by the analog-only host systems.