Thermography
Every object emits thermal radiation/energy in the form of infrared wavelengths and it is these wavelengths that Thermographers identify, capture and then analyse.
Infrared wavelengths are not visible to the human eye and so require specially adapted cameras which identify these wavelengths and convert them into a format that makes them visible to us.
The thermal images that are created, however, do not always reflect the true temperature of an object and it is the skill of the Thermographer to be able to accurately interpret these images.
To explain this a little further, we can use the thermal image of a hot cup of coffee as an example. We can clearly see the motif on the outside, it looks much cooler than the bulk of the cup, yet we know the cup is virtually the same temperature all round. What we are seeing is not a picture of temperature distribution but the radiation intensity of the surface of the cup. The silver motif looks much cooler because it has a low emissivity value compared to the bulk of the cup which has a high emissivity value. Emissivity is the ability of an object to reflect radiation intensity. So the thermal image will only show the radiation intensity differences and not the true temperature differences.
Put this simple example into a high voltage transformer situation, the thermal image may, by an unqualified person, be interpreted as showing the transformer turned off when in fact it is not. This could lead to severe injury or a fatality.
In many applications where thermography is used we are not interested in the quantitative measurement of temperature but we need to identify ‘thermal patterns or ‘anomalies’. Thermal patterns and anomalies are easily detected, for example in identifying the need for or lack of insulation in a wall, or the fact that a horse has poor circulation. In these cases the temperature readings are not important and all we need to do is identify the existence or not of continuity of pattern.
HDS surveyors who carry out and analyse surveys will have attained a minimum of Level 1 in Thermography.
For further information please contact us on 08453 277561 or email: surveys@heatdetection.co.uk