If you’re fairly new to using thermal imaging cameras – perhaps your company has recently installed new insulation or some equipment that’s temperature-critical – then while you’ll know how useful these devices are, you may fall prey to one of the several misconceptions about them.
Read on to debunk any erroneous ideas you may have had.
Don’t forget to use the right units
Thermal imaging cameras are quite easy to use, but you can still make mistakes; a particularly common (and embarrassing) one is to forget whether you’re reading in Celsius or Fahrenheit!
Your camera doesn’t have X-ray vision
It’s tempting to see your camera as a superhero with the power to see through walls! It actually can’t do this; what it does do is to “see” the thermal energy’s first ten-thousandth of an inch as it comes off a radiating surface.
This myth means that lots of people use thermal imaging cameras to search for water leaks behind walls and under floors. A water leak will only show up on a thermal imaging camera if it causes the wall’s temperature conductivity to change. If the water just drips onto the floor behind the wall or under the floor, you won’t pick it up.
Remember emissivity
Emissivity is the measure, or property, of a particular surface to give out energy in the form of radiation. Some surfaces are particularly tricky – shiny metal is a good example. Most thermal imagers will let you set them to handle a particular material or surface, but this isn’t always accurate.
Glass is a particularly problematic surface as well, as it reflects heat and light so well. If you’re standing in front of a window to take the measurement, you could end up seeing your own heat signature! This is easily resolved though – just change the angle at which you take the reading until your image disappears.
Bright and breezy isn’t always the way
Using a thermal imaging camera outside can also fox you as you’ll need to make allowances for wind chill. A mere 10mph breeze can make the reading from an object lower than the object actually is, so you need to be able to factor this into your results. Even inside this can be a problem, if you’re looking at something near a fan, an aircon unit or even a hot air outlet.
Make sure your machinery is working when you do a reading
If you’re scanning machinery or electrical equipment, you must do it while the equipment is running under its usual operating load. You won’t find any leaks or other problems if the machine isn’t doing its usual thing. It’s tempting to turn off the machine or reduce the load on the circuit box to do the measurement, but this is misleading.
A thermal imager isn’t like a handheld temperature gun
Although both devices use infrared light, temperature guns only look at one point and take one measurement, whereas thermal imagers look at thousands of points to create a graded image.
Infrared temperature guns still have their uses, of course; if you know a particular spot has a leak or a problem, such as the corner of one particular window, then this device is ideal.
