ARN: Thermal cameras detect fires at an early stage

Although the NEN 2535, the standard for fire safety of buildings, does not write anything about the use of thermal cameras in fire detection, they are nowadays regularly used and seen as an equivalent solution in certain situations.
Thermal cameras have recently been installed at the high-tech ARN waste-to-energy plant in Weurt (near Nijmegen). In a large ARN transhipment hall of no less than 2400 m2, two thermal cameras are installed for fire detection.
Plastic waste is brought into the hall by trucks.
In the mountains of plastic, there is a risk of scalding, which in turn can lead to fire.
An early detection of a temperature rise is therefore desirable.
Although part of the hall had already been equipped with an aspiration system, ARN wanted to further minimise the risks by detecting an incipient fire even more quickly.
A few years ago, Mactwin renewed the entire fire alarm system at ARN and, as a matter of course, was also commissioned to realise the extension.
Since a modern modular installation had been chosen at the time, this extension could now be connected relatively easily.
The desire to detect heating as early as possible (earlier than the current aspiration system), in a large hall with a height of no less than 15 meters, required a less common solution.
Erik Poulussen, Sr.
Account manager at Mactwin, explains: “Given these circumstances, we opted for thermal cameras. Thermal, or thermal imaging, cameras show heat differences very accurately. The cameras measure the intensity of the amount of infrared emitted by an object. Based on this, the cameras can determine the temperature. In this way, a thermal camera can also detect so-called hot spots, such as ARN heating in a waste mountain. Thermal cameras also have a long range, which allowed us to cover the entire area with just two cameras. In addition, they work excellently at great heights and can be set to signal the underlying fire alarm system when a certain temperature is reached. At ARN, we took into account the specific conditions in the transhipment hall when setting the alarm threshold. For example, the hot parts of the shovels that drive around, such as the exhaust, are not seen. This prevents unwanted fire alarms.”
There was still one problem: thermal cameras are not included in the NEN 2535.
Erik Poulussen: “We have therefore implemented the system in such a way that it is equivalent to the solutions that are included in this standard. For example, it is continuously monitored whether the cameras are still working and measuring. The system is also designed according to the fail-safe principle. As soon as there is a failure of the system, a fault message is sent immediately. Furthermore, an independent inspection agency tested whether the use of thermal cameras in this situation could be seen as equivalent to the NEN, according to established protocols. That was the case. Finally, we have demonstrated with a standardised fire test (see box) that the system meets the set performance requirements. For ARN, this means that this expansion can simply be certified along with the existing fire alarm system.”