Building surveying with IRT: Myths and Applications
Like any technology, infrared thermography (IRT) has many myths and applications. Since we started more than 15 years ago, we have been asked weird and wonderful questions about infrared thermal imaging. Here we look at its myths and applications.
INFRARED MYTH 1: YOU CAN SEE THROUGH CLOTHES WITH AN INFRARED CAMERA.
The answer is simple: No. I am never sure why this is one of the most common questions, but it is. Whilst Infrared cannot see THROUGH anything, it can see the effects caused on the surface. For example, we can see the shape of your shoulders where they touch your cotton shirt — that energy is readily transmitted and emitted through the cotton. Pop on a super insulative jacket and these shoulders will disappear from thermal view.
The same goes for defects in a house or commercial building. A well insulated building looks uniformly the same colour.However, where the heat can escape to the outside or warm the external façade, hey presto, we can see that energy.
INFRARED MYTH 2: YOU CAN SEE PEOPLE GETTING UNDRESSED AT HOME WITH AN INFRARED CAMERA.
Again, a straight No. This is another frequent question we are asked when we are surveying large volumes of homes for local authorities and housing associations. Rightly so. Due to the very nature of social housing provision, residents may be vulnerable or elderly. Someone standing outside a house taking pictures at night will look odd and alarm the residents. It is only natural to assume that infrared thermal cameras could see through glass, like normal cameras can. But infrared thermal cameras are not the same as normal ones. Like ultra violet (UV), infrared can’t pass through glass. Infrared can pass through some plastics however, but not glass. By the way, UV cannot pass through glass either, so there is no point sun bathing in your office with your windows shut!
INFRARED MYTH 3: INFRARED CAMERAS BEAM OUT HARMFUL INFRARED RAYS.
No. Often people assume the cameras are harmful, but in reality they are the same as any other camera. They merely absorb radiated energy from objects and turn that energy into an image. The cameras themselves are 100% safe.
INFRARED MYTH 4: WITH INFRARED CAMERAS PRICES COMING DOWN, IT IS CHEAPER (AND EASIER) TO BECOME A SURVEYOR.
No. Whilst cameras are indeed much cheaper than they were, that cheap equipment will not make you a decent surveyor. Just like buying a voltmeter doesn’t make you an electrician. Nor a saw a carpenter. Over the last 20 years camera prices have fallen from well over £200,000 to well under £1,000 for entry level equipment. Amazing! The technology in them is more powerful and usable. The good news is that many more people have access to this amazing technology. The downside is that many more people have access to this amazing technology. We have seen people buy cameras and survey under the wrong conditions. However, we have also seen people invest in good cameras and survey the right conditions, but mis-diagnose the problem because they didn’t understand building physics or the thermo-dynamics at play.
INFRARED MYTH 5: THERMAL IMAGES CAN’T BE MANIPULATED.
Yes they can. Infrared cameras are digital nowadays and thermal images very easy to change. Within seconds, a good roof can be made to look awful and vice-versa. We have written about this many times before. Analysis really must be undertaken by someone impartial who knows what they are doing. Finding skilled people who can interpret the images correctly, survey professionally and write meaningful reports quickly in plain English is a challenge. When it is time to appoint your infrared surveying company, make sure you conduct thorough research.
So, with the myths out of the way, what can you see with a decent infrared camera for building surveying? Let’s start at the top of a building and work our way down.
BUILDING SURVEYING WITH IRT: ROOFS
Again, we have written extensively about the exceptional value of infrared surveying for leak detection and establishing the right time to refurbish a roof. IRT can literally show you the extent of moisture trapped within your roof. It can help show you where leaks originate, where they track, how and where they enter the fabric and the extent of the damage caused en route to the ingress point. An essential tool if you are putting together a dilapidation report for your client.
BUILDING SURVEYING WITH IRT: WALLS
Gaps in cladding, wet insulation, badly fitted windows, ingress, dampness, mould growth, delamination, voids, condensation, airtightness are all building defects we can identify with infrared. As long as it affects the temperature, we can photograph it.
BUILDING SURVEYING WITH IRT: CAVITIES
Missing cavities, wet cavities or voids in the walls can be seen with infrared. If you have housing stock that was flooded for example, IRT can show you wet cavities, extent of damage to plasterwork beyond what the naked eye would reveal and also show you where any render has debonded from the fabric. Invaluable information BEFORE you repair the damage. Leave that wet insulation in the cavity and within a matter of months the damp will be back and you will end up spending twice.
BUILDING SURVEYING WITH IRT: FLOORS
Failed damp proof membranes (DPM), trapped moisture below concrete, wet timbers, gaps in insulation, pipework below, underfloor heating pipes, any inconsistencies in temperature are easily seen and measured with infrared thermal imaging.
These are the basic applications of infrared thermography. Its most advanced and exciting application, particularly useful for housing associations and local authorities, is the quantification of thermal images and exploitation of the data taken from the images to develop targeted energy efficiency programmes.
Do you have any questions about infrared thermal imaging applied to building surveying? We probably know the answer and if we don’t, we will know someone who does. Do contact us with your queries.
firstname.lastname@example.org — www.irtsurveys.co.uk — 0845 5193 474