IRT – Infrared Thermography is an NDT technique which uses a camera to produce visible images showing the amount of infrared energy emitted by an object. Infrared energy is just outside the visible electromagnetic spectrum and is therefore invisible to the naked eye. The amount of infrared energy given off by an object depends upon the temperature and the emissivity of the object.
IRT is a valuable diagnostic tool. It can be used in passive mode to look at the behaviour of components: to identify electrical components which may be overheating or areas where the lagging has deteriorated on hot pipes and vessels. A common passive IRT image is the picture of a house showing the heat loss through its doors and windows.
IRT can also be used in active mode: heat is applied to a component and the heat flow is imaged by the IRT camera. The heat flow will be distorted by the presence of defects.
Most IRT cameras can image temperatures from –20 to +500°C, although this range can be extended. They can be used to measure temperatures of components. As with all NDT methods, precise and reliable application of IRT requires an operator who understands the physics behind the technique and the equipment and understands the behaviour of the component to be inspected. PCN certification in IRT is available.
For more information on IRT see:
and for IRT qualification requirements see:
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