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October 30, 2017 4:48 pm

Green Wood Dust as Likely to Explode- Says WorkSafe

Thursday, August 16, 2012 @ 3:13 PM
Prince George, B.C.-  Just because a  sawmill is handling greenwood, that doesn’t  mean it is less likely to run the risk of an explosion than those mills dealing with just beetle kill wood.
 
 WorkSafe B.C.  says green wood dust samples were sent to a lab for comparison with beetle dust samples .
 
Tests show, greenwood dust which has less than 5% moisture content and is smaller than 75 micrometers, was just as combustible as the beetle dust.
 
WorkSafe BC says while there was broad speculation in the media about the volatility of beetle killed dust, WorkSafe BC says the investigations are still underway and they are alerting the industry that they must be just as vigilant on greenwood dust as they are on beetle kill dust.
 
“We are confident beetle kill wood is explosive” says Director of Investigations Jeff Dolan “the evidence we are receiving is showing that under all circumstances, all  wood dust can be dangerous.”
 
WorkSafe also noted  wood dust can be in the rafters of the mill, on the surface of  lighting  equipment,  and  as was the case in the  Lakeland and Babine Forest Products  tragedies, at the conveyor level.
 
WorkSafe has been inspecting mills for their dust control measures whether they are milling beetle kill or greenwood.   The investigations on those two  explosions continues.
 
 
WorkSafe has   issued  a release which says :

 

"WorkSafeBC has recently received laboratory test results that conclude that both beetle-kill and green wood* dust pose a high risk of explosion when the moisture content of the dust is below 5 percent and particle size is less than 75 μm (micrometers)*. Dust with this moisture content and particle size is found on elevated surfaces such as rafters, beams, inside dust collectors, and on the surface of air separation systems as well as in hot dry environments such as process equipment and light covers."

In this  case, WorkSafe  considers trees that were living before  being  harvested as "green".

Direction has previously been issued to industry regarding the importance of rigorous dust management procedures and WorkSafeBC is currently engaged in a multi-phase inspectional program. Phase 1 saw the inspection of all sawmills in the province processing either green or beetle-kill wood. Phase II, which began in July, expanded the inspectional program to include other wood processing operations such as pellet and planer mills where dust accumulation could be a safety hazard. Phase III will expand to industries that generate dust from wood and other sources; this would include workplaces that manufacture rubber, aluminum and sugar, for example.

Comments

Well they had to send dust samples to a lab to discover this? Dust explosions aren’t new as a matter of fact when a mill does fire training dust explosions are on the agenda.

Greenwood dust with less than 5% moisture? Are you kidding me? If that tree has 5% moisture when it was cut it definately wasn’t green.

Mills kiln dried lumber target is around 19% moisture content. Less than 19% moisture is considered dry not green.

If you google moisture content of green wood…you’ll discover wood that is considered dried and seasoned is at 20% moisture content. Doesn’t Worksafe know this? Maybe they need to study up a little more? Or is this article error ridden?

I think they’re refering to the moisture content of the dust as opposed to finished lumber. I would think that sawdust dries out quite a bit quicker sitting up in the rafters where it gets hot….

@mercenary, then it’s not green anymore it’s dry. Now maybe they are trying say none beetle killed pine sawdust that is dry is just as explosive as beetle killed sawdust.

To make it easy, just Google “explosive dust”
The Facts about it where known for Ages,why is the WCB revealing this like it would be a new discovery!

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