For companies involved in waste management, spontaneous fires are a fact of life and the critical issue is therefore to detect an outbreak as efficiently as possible and prevent it spreading. For one such company in Sweden, FLIR thermal imaging cameras have played an essential role in this effort since 2016.
Jönköping Energi turns up to 160 000 tons of waste per year – or 20 tons an hour – into heat and electricity, sufficient to cover the annual needs of 25 000 households. Preventing and controlling fires is not only a matter of safety, but also of economics.
“We have trucks bringing in waste not just from the surrounding area but from all over Europe which is dumped in a waste bunker, mixed by automatic cranes and stored awaiting transportation to the boiler,” explained plant manager, Magnus Olsson.
He continued: “These waste piles can be a dangerous mix. Spontaneous combustion from biological products or other heat sources is a continual threat that needs to be monitored 24/7. Apart from the environmental consequences and obvious safety risks, an outbreak of fire can be very costly, up to £100 000 (about R1,7 million) per day. That’s why it is so important to have a reliable early warning system.”
Historically, the plant relied on aspiration-based smoke detection that pulled in air from the environment to analyse it for the presence of smoke. Its main failing was speed. For the system to generate an alarm, smoke had to make physical contact with the sensor which was installed high up in the ceiling of the waste bunker. By the time this happened any fire would have already taken hold.
To provide the sixth sense it clearly needed, Jönköping Energi switched to a system from Termisk Systemteknik, based on FLIR thermal imaging. For fire detection, infrared is a superior technology because it senses the surface temperature of material. In effect, it ‘sees’ the source of the fire in its infancy, before it has the chance to develop.
The chosen system comprises two FLIR A615 thermal imaging cameras in protective housings, mounted on pan-and-tilt systems, one at each end of the bunker. They are controlled via Termisk’s dedicated TST Fire software so that when a hot spot is detected by one camera, the other camera is trained on it too.
The software calculates the co-ordinates of the hotspot, based on the combined thermal images and an alarm is generated. From the waste bunker control room, operators can then direct the water canon to the hotspot to extinguish the fire.
“This system has proved to be very accurate as it is able to measure temperatures to a fraction of a degree,” confirmed Claes Nelsson of Termisk Systemteknik. “Thanks to the high resolution of the two FLIR cameras – 640 x 480 pixels – the entire bunker can be monitored in detail. This enables the control room operators to detect really small hot spots. The FLIR A615 is one of our preferred FLIR cameras for this type of application as it operates with a Gigabit Ethernet interface so it integrates very well with our software.”
Compliance with GigEVision and GenICam standards allows the FLIR A615 to be integrated with a wide variety of similarly compliant equipment and is supported by a choice of third-party software, such as TST Fire. Trigger and synchronisation capabilities enable it to control, or be controlled by a host of other types of equipment. And when used with wireless and fibre-optic line adaptors, this high-performing camera can be used almost anywhere, including over long distances.
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