Let’s look at the influence of atmospheric conditions on thermal imaging surveying. After tech & science, colours, price and company selection, the last episode in our educational series tackles a favourite subject in the British psyche: the weather.
Thermal imaging or infrared surveys are a hi-tech solution to building surveys. They really do move the game on from traditional methods of surveyors with clipboards or tablets relying upon decades of experience, but they are not infallible. Where a surveyor can survey in all weathers, infrared thermal imaging (IRT) is a bit more sensitive to moisture, temperature and humidity.
The influence of atmospheric conditions on IRT surveys
As you are ostensibly taking a picture of energy radiating from an object it makes sense that you don’t want anything to interfere with that radiation. Although the word “radiation” may make you raise your eyebrows, it is all safe. If you have nice dry homes, with the heating on, the sun set two hours ago, it hasn’t rained that day, there is little wind, no fog or mist, then you can survey away and you will get awesome results.
The best atmospheric conditions for thermal imaging surveying are: after sunset, little wind, no rain, fog nor mist, and the heating on inside the houses.
Changing atmospheric conditions
Even with the current excellent weather forecasting capabilities, the best atmospheric conditions are often unpredictable. What can happen and how does it affect IRT surveys?
- Turn up the wind however and all that lovely radiating energy will be blown from the surface you are trying to measure. Poop.
- Wet the surface and double poop. The water cools the surface and absorbs the energy, then radiates it but with a different emissivity to the dry bits.
- Switch the heating off and you lose the difference between inside and outside. As a result, the energy has no incentive to move, so your thermal imaging surveying results will be poor. You will think the building is perfect.
Think about sitting in your lounge nice and cosy; the door to the cold hall gets open and suddenly the lounge feels cold. Why is that? That is due to the large difference in temperature, the heat cannot wait to leave and warm up the hall. Keep them both at the same temperature and you won’t experience this effect.
Another example: Take your cup of hot coffee outside on a cold day. It will get cold fast!
Your house is the same. The laws of physics and thermodynamics remain.
Rain and humidity in general are real no-no’s for a professional thermographer.
Educating clients on thermal imaging surveying technology
As IRT surveys, we conduct Continuous Personal Development (CPD) seminars up and down the UK every week for building surveyors raising awareness of the technology, its benefits and the optimal conditions to use it. We often ask people to think of their buildings inhaling and exhaling energy. To conduct an accurate defect or energy audit we need the building to inhale energy from the sun or your heating system, wait for it to absorb the energy then exhale. An infrared thermal image is an image of that energy being exhaled (or emitted). We can use big words, like thermal inversion, but we find it is better to use plain English in our communications and reports alike.
Once you have appointed your thermal imaging surveyor and they turn up to survey during daylight, rain or high wind , please protect your property and financial assets: get rid of them there and then. Contact us by clicking on the button below.