Caught on camera

Thermal imaging cameras can bring benefits and create new business opportunities for heating engineers. Testo looks at how they work and some useful applications.

Thermography has been established as a valuable tool for diagnosis in the industrial maintenance sector for many years. And with lower-cost thermal imaging cameras now available, heating engineers are increasingly taking advantage of their technical and commercial benefits.

A thermal imaging camera works by capturing information based on the subject’s emitted levels of infrared energy and then converting this into a pictorial representation based on the different levels of infrared.

All objects emit infrared energy, even down to absolute zero (-273°C). However, for most cameras, a working range will typically allow measurements between -20°C and +650°C. We apply a colour palette to the image generated by the camera to help us evaluate it with regard to surface temperature.

It’s important to bear in mind that the accuracy of any apparent surface temperature shown is directly related to the camera having the correct ‘emissivity’ value set for the subject under inspection.

For heating contractors, major uses of thermal imaging cameras are areas with hot water pipework requires faults in pipework to be identified in a property where pipework runs are less obvious, thermal imaging cameras are the perfect tool because they can trace the hot water pipework without causing any unnecessary damage.

Once the hot water pipework than either the pipework run or the background, and this area usually grows in size as the hot water is pushed out into the screed material. suspected area by opening a door or window. that are covered or that are difficult to access. They are ideal for detecting leaks and blockages in pipework and can detect differences in temperature as small as 0.05°C. This level of sensitivity is perfect in situations where pipework is buried in several inches of screed material.

In some cases, creating a higher difference in temperature is necessary to highligh a possible leak site. This can be done by opening all doors and windows to make the area as cold as possible before switching on the heating system at a high setting.

Conduction enables heat to be transferred from pipework and this heat signature can be detected on a flooring surface. When a job has been located, the thermal imaging camera can also diagnose any areas in the system with potential sites of leaks. This is another benefit of a highsensitivity camera, because normal pipework runs will typically show up as ‘linear’ lines of much higher temperature than the background.

Areas with potential leaks will show up as anomalies at a distinctly higher temperature

Thermography can also be used in cold-water pipework detection. Most of the time, the background temperature of the floor will be the same as the temperature of pipework carrying cold water – which doesn’t always allow an adequate temperature difference to be located on thermal cameras.

However, some cameras can detect cold water that has penetrated through the flooring material or screed. This is because the damp area can be detected through the evaporative cooling effect, especially if airflow can be introduced across the

Thermal imaging cameras are not only an invaluable tool for use on traditional heating systems; they are also ideal for the installation and commissioning of underfloor heating (UFH). Thermal imaging can prove both the correct operation and zoning of any UFH system and the correct installation of pipework coils. The ability to prove that the system has been installed correctly and is functioning as it should can be a major benefit in countering against any follow-ups relating to the quality or specification of the work being carried out.

They can also help with the efficient diagnosis of blockages caused by sludge or air causing issues in radiator systems.

They can be used to give your customer a visual report of issues in order to justify powerflushing or any other remedial work that may be needed. ■

•We can clean microbore, one pipe and plastic pipe systems.

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•We can fix blocked systems and blocked heat exchangers.

•No need to replace or re-run pipes.