Sawdust fuelled most sawmill fires

Being involved in helping protect the wood products industries from fires and explosions for the last 3 decades, we have seen first hand the results of many of these types of fires - and the lack of understanding of causes of combustible dust related fires.  As such a complex subject, it is not often someone from the press understands and reports accurately on the causes of industrial combustible dust related fires.  This is a fine article from Gordon Hoekstra at the Vancouver Sun.  It also shines a light on the need for stakeholders to understand the combustible dust problem in these mills, as well as the solutions - efficient dust collection and storage, spark detection, fire suppression, explosion protection, housekeeping etc.

Sawdust fuelled most sawmill fires in last decade

Explosion warning should have been issued: expert

Sawdust, wood shavings and chips, which are suspected to have played a part in two recent deadly sawmill explosions, have also fuelled dozens of fires at B.C. sawmills over the past decade.

Sawdust was listed as the material that first caught fire in more than half of 89 sawmill fires in Interior B.C. between 2001 and 2011, according to B.C. Fire Commissioner incident reports obtained by The Vancouver Sun.

It was ignited most often by sparks (52 per cent), followed by friction heat (25 per cent), hot objects and direct flame (each eight per cent).

The sources of the ignition included bearings, electric panels, welding equipment, cutting torches, wiring, general machinery and in one case a halogen lamp.

The explosive capacity of dust in the sawmills was noted in comments attached to the individual incident reports filed by local assistant fire commissioners, which were obtained under a provincial freedom of information request.

However, the commissioner's office, which is the senior fire authority in the province for fire safety and prevention, could not recall issuing any blanket warnings or cleanup recommendations.

The comments show there was at least one minor dust explosion, as well as separate incidents of a blown fuse that ignited dust, an electric short that caused sparks that ignited fine dust and an overheated motor that caused sparks that ignited sawdust.

The 89 incidents do not capture all sawmill fires in B.C.'s Interior between 2001 and 2011 because not all fires were reported to the fire commissioner's office. The Sun's request was also limited to companies where fires were previously reported publicly in the media.

The fact that sawdust was a major factor in these fires should have provided a warning of the potential danger of catastrophic dust explosions, said John Astad, a combustible dust consultant from Texas.

Forest companies, the United Steel-workers union, individual workers at the two mills that exploded and the province's safety agency, Work-SafeBC, have all said the risk of wood dust explosions wasn't widely known.

Astad said he believes industry and provincial regulators had been lulled into a false sense of security because the fires in the past had not killed people, and the fires often didn't cause significant damage.

The belief that "since nothing bad had happened, [nothing] bad can hap-pen in the future" overshadows the fact wood dust can be an element in a chain reaction that can lead to catastrophic explosions, he said.

"Address the fires and you'll minimize the probability and the severity of a secondary catastrophic explosion," said Astad, who conducted a combustible dust workshop for WorkSafeBC in March 2010 and last month delivered several more public presentations in B.C.

That not only means addressing cleaning at sawmills but adding proper ventilation equipment, he noted.

Sawmills were ordered to clean up wood dust after the second deadly explosion on April 23 at Lakeland Mills in Prince George killed two workers. The first explosion Jan. 20 at Babine Forest Products in Burns Lake also killed two workers.

B.C.'s Fire Commissioner officials said they believe they may have issued advisories about sawdust being an ignition risk before the fatal explosion earlier this year, but could not immediately provide any examples.

Kelly Gilday, the province's deputy fire commissioner, acknowledged the incident reports from the local assistant fire commissioners are meant to provide the fire commissioner's office with information to track trends.

But Gilday said because sawdust is a byproduct of the sawmilling pro-cess, it's the responsibility of business owners to ensure the site is clean of sawdust.

"Even if an inspector goes through a property once a year, there's 364 other days for that material to accumulate," he said.

United Steelworkers safety specialist Ron Corbeil said he's concerned that not all sawmill fires are being reported to the fire commissioner.

"Statistics can identify trends, and that's when things are put into place to ensure we don't have a catastrophe like we had twice," said Corbeil.

There were three fire incident reports filed with the fire commissioner in the past decade for Lakeland Mills in Prince George.
In August 2004, a hot bearing threw sparks into sawdust and ignited wood piled up against a wall, and a fire was started in November 2006 by welding above an area housing wood shavings.

There was also a fire in February 2012 in Lakeland's dust-filtering bag-house where the material first ignited could not be determined.
Sawmill worker Darryl Kennedy said, however, it was started by a portable halogen light that heated dust that ignited.

Still, Kennedy said workers did not generally make any connection between previous fires and the explosive potential of wood dust.
Greg Stewart, president of Sinclar Group, which owns the mill, declined to comment on the fire history at Lakeland.

The fire incident reports also found: . In May 2005 at Tolko's Soda Creek sawmill in Williams Lake, wiring to an electrical motor had loosened and arced, igniting dust and sawdust in the room and creating a "minor" dust explosion.

. In July 2009 at West Fraser saw-mill in Williams Lake, large fuses blew, igniting dust above panels. Fire damage was minimal.
. In October 2006 at Canfor's Prince George Sawmill, an electric short of breakers caused sparks that ignited fine sawdust in the lumber edger. Damage was contained to electrical controls and catwalk.

. In August 2011 at Dollar Saver Lumber in Prince George, sparks from an overheated electrical motor ignited sawdust and hydraulic fluid. The interior walls of the compressor room were charred.
Annotated Response Records


Popular posts from this blog

The Fire Triangle, Fire Tetrahedron and Dust Explosion Pentagon

Introducing the NFPA 652 Combustible Dust Standard