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While invasive testing methods are sometimes necessary to determine the source and extent of moisture problems in buildings, there are a range of tools to facilitate first diagnosis. Electronic humidimeters, surface thermometers, hygrometers and data recorders all have a role to play. For experts such as Brick Tie Preservation in Yorkshire (UK), these are the standard tools of the trade. The company also has its own saltpeter analysis and gravity testing laboratory for masonry samples. Being so well equipped, why did she choose to add thermography to her arsenal?
The answer to this question lies in the ability to "take a step back" instantly and integrate features and defects that influence the moisture problem; these details can be seen immediately on a thermal image, which reveals the differences in heat transfer and retention. Bryan Hindle, CEO of Brick Tie Preservation, compares his thermographic camera to a time machine to learn about the history of the building.
He had been interested in thermography for some time and, after seeking input from other professionals in his branch, decided to enroll in a course taught by Thermographic Consultancy Limited (TCL) in Swindon to learn more about the technology.
"While thermography applied to the building is not rocket science, it requires a good knowledge of how it works and what influences the material and results," says Hindle. "I think a Level 1 qualification in thermography is perfect for anyone who is in this field. I refused to use an IR camera in my work without having taken this training. »
The next step was to choose the most appropriate thermographic camera. Following his training, Bryan realized that an entry-level model would be a last-ditch economy for his company. While a simple model is sufficient to solve simple problems, it does not provide the performance or functional richness required to detect complex problems revealed by subtle temperature differences.
Thanks to the guidance of TCL expert Stuart Holland, himself a Level III thermograph, Bryan Hindle finally opted for the Flir T420bx, equipped with a wide-angle lens, with his company largely involved in the interior of the buildings.
"Flir manufactures quality products and has a good network of professional trainers. That's what I like about a manufacturer. It's a responsible and proactive attitude," hindle says. "I've looked at what other brands offer, but this model offers the perfect combination of functionality, sensitivity and resolution. Having used cheap pistol-type models, I find the ergonomics of the swivel lens and handle much more comfortable. »
"Good sensitivity is a particularly important criterion because I can't count on high temperature differences and I don't have a choice of working conditions," he adds. "Preparation is of little interest if, for example, the doors and windows of a building are wide open when I arrive. In this case, the conditions of intervention are far from ideal. »
Limitation of destructive testing
Although thermography does not directly diagnose situations such as moisture rises, it helps Bryan Hindle refine his judgment of a problem. He feels that it brings a plus to his diagnosis. This is important because many moisture problems are influenced by work done in the past, which is often hidden behind plaster or other finishes. The landlord or tenant may not even know about it himself.
"Thermography helps me make an informed decision about whether tedious and destructive tests are necessary or not. I can get this information on site and usually with immediate results," says Bryan. "Thanks to this technology, I was recently able to show an inspector that a home did not require moisture-tight siding or substantial work, because it was simply a condensation problem."
In this particular case, Bryan Hindle used his Flir T420bx in combination with his Flir MR77 humidimeter. Both devices are equipped with Meterlink, a function that incorporates humidimeter measurements into the thermal image.
"I was able to give my clients an image showing the dew points with relative moisture superimposed on a colour insulated on site, so that it could see the result of live measurements of the humidimeter," Hindle continues. "It's a particularly valuable communication tool and, frankly, I wouldn't imagine buying a camera without this feature. I hate reports that confuse customers. This is why providing the IR image with a clear explanation of what is happening gives such good results. »
Acquisition of knowledge
Not only is it an important diagnostic aid, but Brick Tie Preservation's Flir T420bx allows the company to acquire scientific knowledge. For example, it has been used recently to better understand how saltpeter affects the thermal characteristics of masonry, but also how stale air, common in winter, contributes to increased humidity.
In this particular project, Bryan Hindle used Flir Systems' patented multispectral imaging technology, MSX, to visually represent thermal effects. MSX intercepts the visual data of the integrated digital camera and the thermal camera's radiometric data. The internal software analyzes the image and superimposes its key elements in the form of a very contrasting "skeleton" of the thermal image.
"Thanks to MSX technology, the edge of the passageways, the seat beds and the passage/wall junction are clearly reflected in the image. I also used the excellent tools of Fl'or Systems to materialize some measurement paths to highlight the temperature gradients, as well as the maximum and minimum temperatures visible on each of them," explains Bryan Hindle.
A multitude of applications
For Brick Tie Preservation, the main advantages of thermography lie in its ability to reveal missing or failing insulation, as well as sites with a risk of condensation. It also helps to identify thermal bridges such as clogged cavities. In old buildings, it also helps him find wooden frames and concealed half-timbers, filling openings and leaks.
Lately, the flexibility of this camera has allowed Bryan Hindle to find a leak in a central heating system comprising a hundred meters of piping under the ground floor cap.
"Thanks to my thermographic camera, I spotted the anomaly in just a few minutes. When the heating was turned on, the client and I saw the stain expand and then cool down when cold water was circulated," hindle adds. "All this was detected without having to move furniture, carpets or thibaude. The customer was delighted that the problem was spotted without having to pull anything out. »
"I've been away from thermography for years, but that wouldn't be the case today," he says.
Find out more: www.flir.fr
