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Detection in challenging environments

08 May 2017

WHAT MAKES a workplace special, in terms of the fire-detection capability it requires? This was the question addressed by FFE’s Gareth Dibden in the Fire Safety Seminar Theatre at Fire Safety Scotland.

Three particularly challenging sites, according to Gareth, are waste and recycling facilities, aircraft hangars and heritage properties. Starting with waste facilities, he explained: “Fires that happen at such sites are highly visible and can be very destructive. The smoke generated can cause huge disruption in the local area and there is a significant environmental impact. The main challenges, from a fire-detection point of view, are dust – which can cause false alarms if point detectors are used – and humidity, from dust-suppression systems, which makes the dust tacky and adhere to surfaces, thus obscuring lenses and beams and blocking filters. The mix of fuel types at waste and recycling sites is also a concern, as is the amount of friction – and thus potential for an ignition source – caused by the machinery in use.”

The ideal solution, he suggested, is an IR3 flame detector. “These are highly immune to dust and steam, detect a broad range of fuels and respond extremely quickly. They also provide localised detection.”

Moving on to aircraft hangars, Gareth acknowledged that the incidence of fire in such spaces is low but pointed out that when they do occur, the results can be catastrophic, with the loss of hugely expensive aircraft. Thus, protection of assets is the key requirement here, rather than protection of the hangar itself. He explained: “Ideally, protection needs to be localised to the aircraft and speed of detection is crucial to minimise damage. You don’t want false alarms, either, bearing in mind most hangars will have deluge systems, which cause a lot of mess. Hangars are also enormous spaces, so the likes of optical systems, which are height-limited, are not suitable.”

What would work well, he said, is a UV/IR2 flame detection system for asset protection. “It offers a very fast response time, has high immunity to false alarms and is extremely reliable,” added Gareth.

Finally, fire detection in heritage properties needs very careful consideration because of the substantial cultural and historical loss that can be caused by a fire at such sites. “One of the biggest challenges,” said Gareth, “is the listed status of such buildings. Nobody wants disruption to the fabric and character of the building, so any detection system needs to be very discreet but still effective. Often, such properties have elaborate and high ceilings, making point detectors unsuitable, and the general design – large rooms and long corridors – also present challenges.”

In this case, the most suitable option, according to Gareth, is an optical-beam smoke detection system. “This can easily be hidden in the building, it’s unobtrusive and ideal for protecting large open areas,” he concluded.