It is unusual for more than a few months to pass without hearing at least one report of a fire at a recycling facility. Ranging in size and ferocity, these fires not only present an immediate danger to life but also have long-term consequences, affecting business continuity and costing time and money to put right.
In terms of fire detection, MRFs are one of the most difficult environments to specify for. Fire is a constant risk and varies depending on the nature of the materials and the manner in which they are processed.
As well as the risk of sorting equipment overheating, ‘tramp’ metal can find its way into moving machinery and cause localised hotspots; some materials have been reported to spontaneously combust, such as rubber crumb; and other materials can become explosive if found in a fine (dust) condition.
Understanding the fire risks presented by particular materials, as well as vigilance being demonstrated by staff, is essential as a first line of defence. But in the hot and noisy environment of a recycling facility, the protection provided by reliable fire detection equipment is vital.
In MRFs, dust is a major issue for the effective operation of most detectors. Excessive amounts can lead to inaccurate readings and false alarms. In most other environments, the careful placement of detectors can avoid dusty areas while still providing adequate protection, but within MRFs this is not feasible.
Repeated false alarms can be inconvenient and costly, resulting in downtime for the site.
The other major concern is the nature of fire risk. MRFs may have to deal with extremely flammable and even explosive materials. Electrical equipment needs to be designed so it cannot ignite an explosive mixture in either normal or faulty conditions.
One industry that, at first glance, has few similarities to recycling has helped to ensure that technology capable of meeting these unique set of circumstances exists. The marine and offshore world deals with extreme environments and explosive materials on a day-to-day basis. Fire detection technology designed to meet this challenging environment is now finding a role in recycling facilities.
Flame-proof fire detection equipment has been developed that is contained in a box so strong that an internal explosion (from the equipment) will neither damage the box nor be transmitted outside of it. The surface will remain cool enough not to ignite any explosive mixture.
Intrinsically safe detectors are also available, which operate at such low power and with such small amounts of stored energy that they are incapable of causing ignition in normal conditions or with up to two faults.
The dust issue has also been addressed with the introduction of ‘drift compensation’ into detection technology, which makes allowances for dirt and dust ingress into the equipment while maintaining detection quality.
Because this technology originated in the marine environment, it can operate at high temperatures, often up to 70+°, making it an excellent fit for the recycling industry.
Making a decision about the right technology to protect your facility is not an easy one as there is a bewildering choice on the market. But as technology continues to develop and the recycling industry grows, fire detection is likely to become ever more effective and those horror stories we read about all too often may become a thing of the past.
Paul Pope, business innovation manager at Apollo Fire Detectors