Tuesday, January 28, 2014

Infrared Thermal Imaging


What is it?

Infrared is electromagnetic radiation emitted by objects. Most objects unless at absolute zero, emit some form of infrared radiation. It has longer wavelength than visible light, thus it cannot be seen by a naked eye. Infrared Thermography is referred to detecting this heat signatures of various objects through a infrared thermal camera. The camera detects the infrared light emitted from various objects and shows it as different colors (depending on the palette you choose). Colder objects are shown darker and the hot objects shown lighter.

There is a great deal of confusion in the minds of people about what a thermal image camera can or cannot do. I would like to highlight few points here!

1. Infrared red camera does not have an x-ray vision. It cannot see through walls or objects. There have been instances when an Home Inspector was analyzing the house during Home Inspection and the people are scared and don't want to be in the field of view fearing it can see through the clothing. Well, it does not have any such ability. Again it does not have an x-ray vision.

2. The infrared camera does not emit any radiation. It just a devise to detect the infrared heat signatures emitted or reflected by any object.

3. It is not a magical devise and require favourable conditions and great deal of skill and experience to interpret the findings. Furthermore, the findings required to be substantiated by moisture meter. There has been instances where due to lack of experience and knowledge people have given wrong diagnosis. Believe me its very easy to get excited and to be fooled by this devise. Always consult a professional trained and experienced in both building construction and thermal imaging for proper diagnosis.

4. It is not a digital camera (few models have digital camera built in as additional feature). It only detects the heat signatures emitted or reflected by the objects. Therefore, it needs DELTA T which is the difference in temperature between the objects or inside and outside of the building to display and work properly. When the difference in temperature between inside and outside is very low or almost equal it will not work properly.

Working with and operating thermal camera and interpreting its images require great deal of skill and experience. Its very easy to go wrong or arrive at the false diagnosis.