IR fire detectors

Fire detectors Depending on application and property of the detector fire detectors are selected based on matching. Major types are IR fire detectors, smoke detectors, heat detectors, etc. to name a few. 

Fire detectors generally fall within one of three categories heat, smoke, and flame. Heat detectors work by sensing the heat from a fire. Smoke detectors sense the combustion products from the fire. Flame detectors identify flame by sensing the IR or UV light it emits. 

The IR/UV flame detectors are used to sense fires. Flame detectors that use only IR or UV can experience false alarms. The IR/UV detector is designed to recognize a different type of flame signature from the detectors while rejecting common false sources. When the conditions of any one of the several fire conditions are met the detector indicates a fire. IR/UV flame detectors generally have a cone of vision from 60 to 120-degree solid cone field of view. 

For incandescent fires, optical fire detectors should be used. These may be UV detectors, IR detectors, or closed-circuit TV (or a combination of these). The choice will depend partly on the type of flame that is anticipated. For example, methanol bums with a nearly invisible flame, so a fire of this material cannot be detected by CCTV. 

Typical applications for these high speed IR detectors are characterized by strictly controlled, dark environments where a flash fire could originate. While simple high speed infrared systems have been available for several years, modern sensor and filter developments, coupled with state-of-the-art electronics, have resulted in systems tailored for the munitions industry. These systems are more selective within the electromagnetic spectrum, fast in response, and extremely flexible in application to suppression systems. 

When dealing with an entire fire detection system that utilizes more than one type of detector, a Detonator Module greatly expands the flexibility and capability of the system. An individual Detonator Module can accept multiple inputs from UV and IR controllers, other Detonator Modules, manual alarm stations, heat sensors, smoke detectors or any contact closure device. In the event of a fire, any of these devices will cause the internal fire circuitry of the module to activate the detonator circuit, sound alarms, and identify the zone that detected the fire. When properly used, a Detonator Module will add only one millisecond to the total system response time. See Figure 8 for an illustration of a fire detection system with a Detonator Module. 

Deluge systems should generally be activated by automatic means. Activation by manual means defeats the objective of installing a deluge system, and fire water monitors should be provided instead as they are more cost effective where manual means is relied upon. Most systems provided at petroleum facilities are typically activated by a heat detection. Usually a fusible plug pneumatic loop detection system or UV/IR detectors are placed around the equipment. This insures activation when operators are not present and only when a real fire situation is present. 

Flame detector Senses either ultraviolet (UV) or infrared (IR) radiation emitted by a fire. 

The available types of flame sensing detectors are ultraviolet (UV), infrared detection (IR), combination of these, and monitored closed circuit television (CCTV). These devices operate on the detection of certain wavelengths of light emitted by flames. They are used when there is a potential for fires that rapidly produce flame such as flash fire. 

A fire occurs in four distinct phases. In the incipient phase, warming causes the emission of invisible but detectable gases. In the second phase, smoldering, smoke is formed so smoke detectors can be used. In the third phase, when the ignition temperature has been reached, flames and their emitted radiation (IR and UV) can be detected. In the fourth and last stage of the fire, heat is released the temperature of the space starts to rise, and the use of thermal sensors becomes feasible. 

A review of the data and high-speed movies taken of the tests indicated that smoke may have prevented IR detectors from seeing the fire soon enough to prevent flame propagation. A detector was added within the hopper, and this sprinkler system arrangement effectively prevented propagation in three consecutive trials. 

Fire and Smoke Detection Fire detection systems and alarms should be considered in hazardous locations. These include gas, thermal, smoke detectors, thermal detectors, as well as IR/UV flame scanners... 

Extension of vision into the IR region is rare. Rattlesnakes have IR detectors to allow them to locate prey, and some types of beetles and butterflies use perception of the near IR to detect forest fires. Some IR sensitivity has been observed in goldfish and mantis shrimp, but the reason for this adaptation is less obvious. 

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