“Thermography can be applied in any situation where a problem or condition can display itself by means of a thermal difference.“ Property managers and building owners, maintenance and process engineers, manufacturing companies and facility managers of all types are always concerned with the condition of their facility and equipment under their care. All would agree that proper maintenance, management of energy resources and quality of construction are necessary for optimizing safety, performance and cost savings.
Infrared thermography is such a valuable and versatile tool that we cannot possibly list all the applications. New and innovative ways of using the technology are being developed everyday. Thermography can be applied in any situation where a problem or condition can display itself by a thermal difference. For many situations, this is quite easy to apply; a thermal condition can be seen because the process involves release of thermal energy.
Emissivity is a term used to describe how efficient a material is at emitting infrared energy as compared to a perfect emitter of infrared energy. Emissivity is an efficiency factor and is dependent on the material properties; the objects surface characteristics, and the temperature of the object. Determining the emissivity is critical when measuring temperature on the infrared camera.
Infrared Thermography is the technique for producing a visible image of invisible (to our eyes) infrared energy emitted by objects. The higher the temperature the more energy emitted. The typical infrared thermography camera resembles a standard camcorder and produces a live TV image of heat radiation. The camera provides a basic grey scale image, which is converted to false color images to make interpretation of thermal patterns easier. An infrared camera will also measure the temperatures of the target object. The thermal image produced by an infrared camera is called a Thermogram.
Any condition when the thermal gradient of the surface temperature deviates from the normal uniform thermal pattern that should exist for that particular component.
Detectors in the infrared camera convert this incoming infrared energy from the infrared spectrum to the visual spectrum so we can see the infrared energy. These visual maps that co-relate image intensity or color to the amount of infrared radiation received from that object. The amount of radiation received, along with other parameters, is used to calculate the actual surface temperature of the target object. The detectors are extremely sensitive to small temperature differences. With a trained and experienced Thermographer, inspections are accurate and very valuable.
Everything on this planet contains thermal energy and therefore has a specific temperature. This thermal energy is emitted from the surface of the material. This energy is called is infrared (IR) radiation. The amount of IR radiation emitted at a certain wavelength, from the surface of an object, is a function of the object’s temperature. This is a very important concept, since it implies that one can calculate the temperature of an object by measuring the infrared radiation emitted from it.
“Electromagnetic radiation is categorized by wavelength or frequency.” We know that infrared radiation is a form of electromagnetic radiation, which is longer in wavelength than visible light. Other types of electromagnetic radiation include x-rays, ultraviolet rays, radio waves, etc. Electromagnetic radiation is categorized by wavelength or frequency. Broadcast radio stations are identified by their frequency, usually in kilohertz (kHz) or megahertz (MHz). Other spectrums are categorized by their wavelength. The unit of measurement used is the micrometer, or micron, (m) which is one millionth of a meter. The visible part of the electromagnetic spectrum falls between 0.4 and 0.75 micrometers. We can see colors because we can discriminate between different wavelengths. The infrared cameras detect radiation in the 8 to 12 micrometer band we usually call “longwave” or between 3 to 5 micrometers and is termed “shortwave.” Most commercial infrared detectors today use the longwave spectrum.
Infrared energy is part of the electromagnetic spectrum and behaves similarly to visible light. It travels through space at the speed of light and can be reflected, refracted, absorbed, and emitted. The wavelength of IR energy is about an order of magnitude longer than visible light, between 0.7 and 1000 µm (millionths of a meter). Other common forms of electromagnetic radiation include radio, ultraviolet, and x-ray.