Putting out the flames

Thermal imaging technology has let the waste management industry prevent fires before they ignite.

Fires are fast becoming a concern at Australia’s waste management facilities, as operators seek to minimise their risks through monitoring.

Such conscientious monitoring has been sparked by new research which has begun to look into the cause of the issue. In June of 2016, the University of Technology Sydney (UTS) released a report prepared for the Commonwealth Department of the Environment into waste fires in Australia. The report, titled Waste Fires in Australia: Cause for Concern?, found waste fires can arise across all stages of the waste management chain, both publicly and privately owned, including waste collection, transport, transfer stations, recycling and disposal to landfill. The source of combustible material varies greatly and includes tyres, used oils, green waste, wood waste, solvents, batteries and municipal solid waste.

It noted that research has shown prevention is cheaper than the cost of fighting waste fires and clean-up after a fire has occurred.

Property damage, waste facility downtime, environmental clean-up costs and long-term health effects are just a few consequences of a fire. The report into the causes of waste fires in NSW found that for a majority of cases, the causes were unknown, with the next biggest cause being arson, followed by spontaneous combustion and the dumping of hot coal/ash. The report also found more than half of all waste sent to landfill is potentially flammable. Some recommendations for effective site management include maintaining good security, prohibiting deliberate burning on landfill sites and correct storage of tyre stockpiles.

The cause of spontaneous combustion is just one of many risks looming within Australia’s waste transfer stations. The process of sorting the various types of waste deposited at transfer stations is a volatile one, with the risk of fire ever present.

And the risk is much higher at waste transfer stations than landfills, says Tim Snell, Industrial Monitoring & Control Managing Director, due to their position in residential areas and stockpiling of flammable materials, such as paper and green waste.TAV-2

“Traditionally, when everything was going to landfill, it would all get squashed and buried. With more transfer stations opening up in place of landfill, the risk of a fire is greater. This is because these environments are open air.

“The repercussions of a fire are much higher too, because you’re in among houses and your social license to operate is dependent on you not causing disruption to the businesses and houses around you.”

UTS’s report argued correct storage of tyre stockpiles and hazardous chemicals would reduce the risk of fires. Many of the examples in the report of previous fires were also linked to excessive stockpiling.

Cleanaway is one waste management company to implement new technologies to reduce risk. Its Dandenong Transfer Station, which opened in May of this year, uses FLIR (forward looking infrared) thermal imaging cameras, part of an early fire detection system designed by equipment suppliers Industrial Monitoring & Control (IMC). Sean Towner, Sales Manager, FLIR Systems Australia, says thermal imaging technology has gained momentum in the waste industry over the past 10 years, particularly with more transfer stations cropping up. Sean says that thermal imaging differs from traditional fire detection devices. These systems can detect heat before a fire even starts.

“Prior to the use of infrared you would have CCTV – normal visual. There’s a couple of issues with that. If you’re looking at a potential fire in a visual, the horse has bolted because by the time the CCTV picks up a plume of smoke, the fire has probably already started. With infrared you can pick up the source of heat much earlier and assess the risk,” Sean says.

And when it comes to reducing the risk of fires, Cleanaway’s Head of Major Programs Mark Sheridan says the latest best practice technology is included across all of the company’s infrastructure plans.

“We want to ensure we have class leading preventative tools to protect our people, our assets and the communities in which we work. Stockpile management is the key to a successful and safe working environment for all, strongly aligned with our core value of home safe,” Mark says.

Because human beings can only feel heat rather than seeing it, infrared radiation is measured through thermal imaging technology. Sean says that the human eye sees only a tiny fraction of the electromagnetic spectrum, which is a collective term to refer to the entire range of frequencies of electromagnetic radiation – the different kinds of energies released into space by stars. These include heat – measured through infrared radiation, microwaves and radio waves. Thermal imaging technology can detect heat levels by measuring electromagnetic radiation, producing images of that radiation called thermograms. The amount of radiation emitted by an object increases with temperature, which appears on the thermal image in colours representing a variety of temperature levels.

“Within the electromagnetic spectrum are radio waves, microwaves, gamma waves, infrared and visible waves. Our eyes are only attuned to visible waves. Our eyes can’t see heat, which is the precursor to fire, whereas infrared is able to pick it up,” Sean says.

IMC use FLIR’s radiometric thermal cameras to detect heat that should not be present. Tim says radiometric thermal cameras are calibrated, which means every single pixel of the image provides an exact temperature measurement. The cameras are configured with temperature thresholds and are integrated into an automatic alarming system to provide operators with rapid notification of a risk.

“There is straight thermal imaging where you wouldn’t be able to measure temperature, but you still see an image and there’s radiometric thermal imaging which can measure temperature in a variety of locations,” Tim explains.

Read the full story on page 12 of Issue 13 of Waste Management Review.