Using thermal imaging to find leaks

New technologies are entering the market faster than ever before. Often new products are quite expensive during the introduction phase, but once the first consumers have appreciated them and mass production has started, the prices come down fast. The cell phone is one striking example: it was initially quite bulky and expensive, but it quickly became a product that fits in the palm of your hand and is used by millions of people every day.

It was more or less the same with infrared cameras. The first commercial infrared cameras in the 1970s were big, cooled with liquid nitrogen and cost a fortune. In 1997, an uncooled thermal sensor, also called a microbolometer, was introduced. This detector had no moving parts and was therefore less prone to breakage. Also, microbolometers are cheaper to manufacture, allowing thermal imaging manufacturers to reduce the price of their products. Thermal imaging cameras have become smaller, lighter, and more convenient to use. There were attachments on cell phones, allowing to get an infrared image on the display, as well as so-called “visual pyrometers” – devices with matrices 80×60 elements or similar, which many people mistakenly call thermal imagers.

Now the market is literally flooded with inexpensive infrared devices, which almost everyone can buy. Various thematic forums, bulletin boards and numerous websites are full of advertisements offering “search for leaks with an infrared camera” or “detect hidden water leaks with an infrared camera. Unfortunately, such ads are often published by people who are far from thermography, have no special education and experience, and use cheap infrared devices, unsuitable for this kind of work. Of course, non-contact moisture detectors are widely used for detecting leaks in apartments and making a general picture of any problems with the property. Nevertheless, many people do not fully understand the physical principles and limitations of such tools, so there are many myths and misconceptions about their use. This applies especially to thermal imaging cameras.

Basically, any tool is only a valuable asset when it’s in the hands of an experienced person. Skill, knowledge and inspection methods are the predominant factors when it comes to assessing whether there are problems with a property or if there are risks of problems. This is especially true when detecting problems such as water leaks in apartments and buildings.

So what does a thermal imaging camera actually “see”?

There is a lot of confusion around what infrared cameras can actually do. To avoid the problems that arise from this confusion, you need to understand the technology used in thermal imaging cameras. First of all, it needs to be made clear that infrared cameras can’t detect moisture at all. Based on the intensity of the thermal radiation of an object, thermal imaging cameras determine the temperature, display it visually, and that’s it!

An infrared camera can no more tell if something is wet than a mercury thermometer can when it is dipped in a glass of water. It does not “know” if an object is wet, but it can easily measure temperature variations, and water is extremely sensitive to these variations. Infrared cameras do not “see” water, but rather visualize the effect of water on the temperature of surfaces as a result of the evaporation process. In this case it is clear that temperature contrast is very important for a thermal imaging camera to be able to display the source of a potential leak on the screen. Typically this contrast is clearly visible when inspecting heating pipes, but in the case of cold water or sewer leaks the contrast is highly dependent on the severity of the leak as well as its depth from the surface. Also, an apartment with a water leak can reach temperature equilibrium even after the water has been removed. When this happens, if the damp drywall or cement screed under the ceramic tile has the same temperature as the surrounding air, the thermal imager won’t be able to “see” the temperature difference between the materials. This is especially true for inexpensive thermal imaging cameras with low temperature sensitivity and low matrix resolution. This situation can be corrected by turning on the air conditioner or even by opening the door to create a draught. Such actions instantly affect the temperature of humid areas due to the effect of evaporation.

To detect a leak in a wall (or find a leak in a radiant heating system) you need a thermal imaging camera with high resolution and thermal sensitivity, as well as level and range settings. Many people try to use an inexpensive entry level thermal imaging camera to detect moisture, but it is doomed to fail about 60% of the time, because the lack of temperature sensitivity and the lack of level and range adjustment make it impossible to visually see wet spots on the screen of such devices.

It is important to entrust the search for a leak to a competent specialist

When telling the customer whether an area is wet or not, the thermal imaging camera operator uses temperature, not the actual humidity level, as his argument. Some dishonest “experts” may take advantage of customers’ inexperience by pointing out the colorful visual effects shown on the Imager’s display. Images of wall areas with bricked-up cold water pipes and ducts may give the impression that the area is humid, when in fact it is only thermally cooler than the surrounding areas. A “hot” spot on the route of a heat pipe that is in a floor screed may not be a leak at all, but a connection socket or outlet.

If a thermal imaging camera is used incorrectly, or if the landlord is deliberately misled, the images on the screen of the camera can lead to false conclusions and unnecessary repairs. However, when it comes to positioning yourself as a leak detection expert, an infrared camera and the visual effects it provides can demonstrate to an apartment owner or business owner that using these advanced technologies is a sign of professionalism.

When used properly, a thermal imaging camera can be one of the great tools you use when searching for leaks. But remember, it is only a tool and should always be used in conjunction with other instruments, such as moisture meters and leak detectors, to ensure that the anomaly detected by a thermal imaging camera is in fact a leak. A competent leak technician will use the moisture tool to find out the true picture of moisture intrusion and to confirm or deny the results of a leak detected by a thermal imaging camera.

You can’t find leaks with thermal imaging alone!

The the most common tool is water leak detection used for home inspections. It measures moisture at a depth of 20 to 100 mm below the surface, depending on the model and sensor used. Like a thermal imaging camera, the moisture meter is only an indicator and in non-contact mode its readings are relative. Nevertheless, in the hands of an experienced leak technician, the moisture meter is an important device to provide additional evidence of possible moisture intrusion. It is extremely important to understand that diagnostic instruments must be used by a person who is trained, skilled and experienced to, using a variety of methods and tools, piece together the evidence and interpret it correctly to accurately report the results.

Despite these seemingly obvious findings, the use of thermal imaging cameras still causes a lot of myths and misconceptions. They don’t detect moisture and they certainly can’t see through walls. Basically, they detect thermal radiation, which forms an image that shows changes in surface temperature. Cooler areas can indicate the presence of moisture or leaks, but they require additional inspection with a moisture meter and other instruments. Using thermal imaging alone is very risky. Without confirming a leak with various methods and devices, the results of a thermal imaging camera search for a leak will not be reliable and will not be sufficient for making decisions.

We would like to point out that a thermal imaging camera can also show a “uniform thermogram” without any suspicious spots, but that does not mean that there are no problems. For various reasons they simply could not have been detected by this tool on that day. The best and safest way to identify leaks is to call on the services of experts who have been dealing with leaks for a long time and have a whole suite of different equipment in their arsenal to find problems in apartments. Our professionals use a full arsenal of modern, high-tech equipment, including a professional thermal imaging camera, moisture meter, inspection camera, and various leak detectors.