Sometimes a standard smoke or heat detectors isn't practical for use. In those instances we use specialized detection
Air Sampling (High Speed Early Warning) Detection uses laser-based particle counters or cloud chambers to sample air drawn in through a piping network. These systems can sense a potential fire long before it becomes a serious threat.
Air sampling detection is also used in areas where it is inconvenient to continuously access remote detectors for service (since the “detector” is the same as the control panel and only piping with ports for air intake are located in the field. Applications include high ceilings, freezer warehouses, and “dirty” environments such as steel and power plants.
Linear Heat Detectors
Linear Heat Detection consists of a pair or more of wires that operate as heat detector when a fire occurs at any point along their length. Since conduit is not required the installation cost can be greatly reduced. These systems typically have options for a distance location meter to help pinpoint the source of the alarm.
The most common type of this system consists of a pair of wires with an insulator set to melt at specific temperature allowing the two wires to short and sound an alarm. It can be provided in a variety of jackets that are designed for indoor, outdoor, and caustic environments. Systems vary in length from only a few feet to thousands of feet. A fiber optic version can provide detection for up to 5 miles at a time.
Applications for linear heat detection are typically long linear hazards such as coal conveyors, cable trays, warehouse racks, pipe lines, tank farms, mines, etc.
Flame Detection is used for open area detection. There are a variety of flame detectors using IR (infrared), UV (ultraviolet), and multi-spectrum detectors that use a combination of IR, UV, and visible light. Multi-spectrum detectors have made it possible to use flame detection in areas that previously were subject to false alarms from environment conditions from other types of flame detectors.
Flame detectors are used in a wide variety of applications, but most commonly (1) outdoors where smoke detection cannot be installed and heat detection is too slow or (2) where fast growing flame front fires can be a concern.
Common applications for flame detection include refineries and tank farms, truck loading racks, gas turbines, automotive paint lines and paint mix rooms, powder coating lines, and semi-conductor production.
Spark Detection (or Ember Detection) is similar to flame detection, but very specialized. This type of detection is nearly always used in duct-work for exhaust systems leading to dust collectors / bag-houses. Spark detection looks to detect as spark in the duct-work and extinguish it with a special fine water mist before it reaches the dust collector (where is can cause fires and explosions).
Common applications for spark detection include wood furniture makers, paper mills, and agricultural processing.
Video Smoke Detection
Video Smoke Detection is also similar to flame detection. In this case, the similarity is in the idea of viewing an open area for evidence of a fire. In the case of video smoke detection, the system’s ability to detect a fire is based on computer analysis of the visual data. The processor looks for specific motion patterns of smoke and fire (while ignoring other onscreen movement patterns.
Applications include large open areas where traditional smoke detection may be impractical or inefficient, buildings with high ceilings, areas with high air movement, etc.