Flame Detectors: Definition, Types, Uses, and How to Choose

Flame Detectors: Definition, Types, Uses, and How to Choose

What are flame detectors?

A flame detector is a sensor that detects and responds to a fire or flame. The detection and response methods vary to fit the needs of many different use applications. Flame detectors are useful in any situation where fire poses a risk to personnel and/or capital equipment. Industrial applications include settings such as oil and gas pipelines, turbine enclosures, off-shore platforms, manufacturing facilities of all types, aircraft hangers, munitions plants, chemical stores, power plants, transformer stations, nuclear facilities, and more. 

How do flame detectors work?

Flame detectors vary in design, but most flame detectors consist of a photoelectric detective circuit, a signal conditioning circuit, a microprocessor system, an I/O circuit, and a cooling system. The flame detector sensor is sensitive to glowing embers, coals, and flames that have the energy and spectral quality to activate the detector. Depending on the design, detectors can respond to energy ranging from the visible spectrum to the infrared (IR) and ultraviolet light (UV) spectrums. Some flame detectors are only activated by specific spectrums, and some respond to a wider range of spectrums. The sensors detect radiation emitted by a flame, and convert the radiant intensity signal into a voltage signal. The voltage signal is processed by the microchip computer into an actionable output signal. The output signal is disseminated through the communication circuits to a fire alarm or flame detector control panel to emit an audible and/or visual alarm. A flame detector can also connect to a site monitoring system. 

Installation Considerations

Flame detectors should be installed to optimize the viewing angle and detection range of the device within high-risk fire ignition areas. Consider and remove potential obstructions such as beams, girders, and other environmental features. 

Types of Flame Detectors

UV Flame Detectors

UV flame detectors are sensitive to wavelengths shorter than 300 nanometers. From the instant of ignition, it takes the detectors 3-4 milliseconds to detect fires or explosions. UV sources such as lightning, arc welding, and sunlight can trigger false alarms. Time delays lasting 2-3 seconds are often included in UV flame detectors to reduce the occurrence of false alarms. UV flame detectors are beneficial because they offer a high-speed response to hydrocarbon, hydrogen, and metal fires. They may pose challenges because they respond to common industrial occurrences of UV light like welding, sparks, etc. 

IR Flame Detectors

IR flame detectors are sensitive to the IR spectral band which ranges from 700 nanometers to 1 millimeter in length, but single frequency IR flame detectors are most sensitive around the 4.4 micrometer range. For context, IR waves are shorter than radio waves and longer than UV waves. These devices use thermal imaging cameras to detect the spectral pattern emitted by hot gasses. False alarms can be activated by ovens, heat lamps, etc. The typical response time is 3-5 seconds from ignition to alarm. 

UV/IR Flame Detectors

UV/IR flame detectors are capable of detecting both UV and IR radiations. UV/IR flame detector consists of ultraviolet (UV) and infrared (IR) sensors that are joined together in a single apparatus. This combination provides a fast response time and increased false alarm immunity against sources of radiation for reliable protection. While the UV sensors detect the UV radiation-emitted flames, the IR sensors monitor the infrared emission spectral band around the 4.3 to 4.4 micron range – the predominant radiant emission band for hydrocarbon-fueled fires.

Multi-spectrum IR

The multi-spectrum infrared (MSIR) flame detector has the longest and widest detection distances and enhanced false alarm immunity.   This technology is typical for fires such as alcohol, n-heptane, gasoline, jet fuels and hydrocarbons also includes the capabilities to see through dense smoke produced by petroleum products.

How to Choose a Flame Detector

To select a flame detector, evaluate the nature of the potential fire, environmental conditions, and protection needs. The flame detector must be appropriate for the dimensions of the protected area and the radiation characteristics of the flame. The detector capability and response time must match the requirements of the setting. 

Buying a Flame Detector

The best way to buy a flame detector is to consult an expert supplier. TechStar is your manufacturing representative for instrumentation, automation, and analytical products, service, and training. For over 20 years, TechStar has been the leading provider of quality flame detectors.

TechStar expertly curated the following selection of flame detectors:

  • The FlameGard® 5 MSIR Detector is an advanced multi-spectrum flame detector designed to provide superior false alarm immunity with the widest field of view. The detector employs a state-of-the-art multi-spectrum infrared (MSIR) sensor array with a sophisticated Neural Network Technology (NNT) system.
  • The FL500 UVIR Flame Detector delivers high speed flame detection with increased false alarm immunity in a compact design. The FL500 UV/IR Flame Detector monitors for radiation emitted by a flame in both the ultraviolet (UV) and infrared (IR) spectral ranges. This UV/IR combination provides a fast response time and increased false alarm immunity against sources of radiation for reliable protection.

To acquire the best flame detector for your site along with training and support for optimal use, contact TechStar today!

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