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Friday, January 17, 2014

Burns Lake sawmill explosion was preventable

Burns Lake sawmill explosion and fire called preventable - British Columbia - 
From CBC News

"No criminal charges are being laid, however. Last week, Crown counsel revealed it would not bring charges against the owners of the mill, saying WorkSafeBC's investigation didn't follow the rules for conducting criminal investigations and as a result a large amount of evidence would have to be thrown out."

"The various statements from the Babine mill workers certainly indicate that beetle-killed wood was producing more and finer dusts and waste than typical green wood."


Burns Lake sawmill explosion and fire called preventable

Premier orders surprise review of probe into blast that killed 2 workers

CBC News Posted: Jan 16, 2014 2:05 PM PT Last Updated: Jan 17, 2014 9:04 AM PT
Premier orders mill explosion review
Premier orders mill explosion review 2:15
B.C. Premier Christy Clark has ordered a review of the investigation into the Babine Forest Products sawmill explosion and fire in Burns Lake, B.C., that claimed two lives and injured 20 others in January 2012.

The long-awaited WorkSafeBC report released Thursday finds the disaster could have been prevented if mill management had been doing its job.

No criminal charges are being laid, however. Last week, Crown counsel revealed it would not bring charges against the owners of the mill, saying WorkSafeBC's investigation didn't follow the rules for conducting criminal investigations and as a result a large amount of evidence would have to be thrown out.

Clark says the people of Burns Lake deserve an explanation.

"That's why I've asked the head of the BC Civil Service, Deputy Minister John Dyable, to review the case  — to review the fact pattern, come back and give us the facts so that we know and understand what happened with the investigation and the decisions around it."

Mill management blamed

In the final report of its investigation into the incident, WorkSafeBC says sawmill management had known for some time that the dust collection system was undersized for this type of operation and had even made a down payment on a replacement.
'The accumulations of wood waste before the explosion … indicates that supervisors were not effectively or adequately monitoring the work that was being done.'-WorkSafeBC report
Unfortunately, the mill's electrical supply could not handle the additional load of the new dust collection system.

"An electrical upgrade was planned, but instead of curtailing production until the upgrade was complete, production levels were increased instead."

The 87-page report finds the explosion was caused by a buildup of wood dust that was ignited by rotating belts near a conveyor-belt motor.

Sawdust on Mill Motor
A view of the conveyor belt assembly shows sawdust accumulation. (WorksafeBC repĂ´rt)

"The dust was compacted and subjected to near constant friction from the rotating belts and sheaves. It caught fire and ignited the airborne wood dust that was dispersed in the area. An explosion and subsequent fire travelled through the mill, disturbing and dispersing the accumulated wood dusts and setting off secondary explosions that totally destroyed the mill, killing two workers and injuring 20, many seriously."

The WorkSafeBC report puts the blame squarely on a lack of supervision.
"The accumulations of wood waste before the explosion and the poor condition of some of the electrical equipment that was inspected after the incident indicate that supervisors were not effectively or adequately monitoring the work that was being done."

Workers deaths examined

The report also looks at the circumstances surrounding the death of the two workers. It says the booth operated by the cut-off saw operator was directly in the path of the explosion as it expanded north and west, fed by the wood dust in the air.

Burnt out Mill damage
An aerial view shows the east side of the sawmill. The large yellow arrow indicates the easterly direction of the explosion’s expansion from the point of origin (WorksafeBC report)

"The over pressure (from the explosion) breached the north wall and vented outward into his location. The operator’s booth was destroyed and the #1 Cut-off Saw Operator died while still in the booth."

The report says the lead hand was found inside the doorway of the round saw filing room in the sawmill's basement where he had gone to perform a variety of system checks.

The mountain pine beetle-killed wood used by the mill may have also been a factor in the accumulation of dust in the mill.  The report finds that decreasing amount of moisture in dead pine adds challenges to industrial sawmill operations.

"The various statements from the Babine mill workers certainly indicate that beetle-killed wood was producing more and finer dusts and waste than typical green wood."

WorkSafeBC recommendations

The worker safety agency says it's taking the following steps to prevent future disasters:
  • A directive order to every sawmill in B.C. to undertake a comprehensive risk assessment with respect to hazards created by combustible dusts and develop and implement an effective combustible dust control program.
  • Followup inspections of sawmills by WorkSafeBC prevention officers.
  • The expansion of inspections to similar wood-processing operations where dust accumulation could be a hazard.
  • The issuance of hazard alerts on the increased risk in winter of combustible dust.
Read the full WorkSafe B.C. report
WorkSafeBC says its report only addresses the cause of the sawmill explosion. However, it is currently considering enforcement action against the company under the Workers Compensation Act.
WorksafeBC report

Monday, January 13, 2014

OSHA Guidance on Combustible Dust Hazards

OSHA Issues Guidance on Combustible Dust Hazards Under New HazCom Rule
From Bloomberg BNA


By Robert Iafolla
Jan. 2 — When chemical manufacturers and importers lack direct experience with the combustible dust hazards of products they're shipping, they should use laboratory testing, published test results or particle size to classify them under the new hazard communication standard, according to an Occupational Safety and Health Administration memo released Dec. 31.

Manufacturers and importers are responsible for considering the combustible dust hazards of the chemical in the form they're shipped as well as those that might stem from normal use and foreseeable emergencies, OSHA said in its memo.

OSHA's standard interpretation memo is designed to guide agency inspectors in deciding whether products are classified properly for combustible dust hazards. The guidance is for inspections of manufacturers and importers, typically from referrals regarding faulty labels or safety data sheets, rather than for inspection of downstream users. Companies must comply with most provisions of the rule by June 2015.

Guidance Amid Uncertainty

The standard's handling of combustible dust has emerged as an area of great concern for industry, with some advocates claiming that the agency engaged in backdoor rulemaking by including combustible dust in the hazard communication rule. The regulation's treatment of combustible dust is the subject of an ongoing legal challenge in a federal appeals court.

The standard itself doesn't define combustible dust, pointing to ongoing OSHA rulemaking and efforts at the United Nations as a reason for that absence. Instead, the rule cited existing guidance on combustible dust, such as the agency's national emphasis program on the substance.

Given that uncertainty, the memo should be useful to companies by providing several different approaches for classifying a substance's combustible dust hazard, Daniel Levine, president of Product Safety Solutions, told Bloomberg BNA Jan. 2.

The material in the memo is consistent with previous combustible dust information published by OSHA, said John Howell, vice president of GHS Resources Inc.

“However, it might give some classifiers heartaches who hadn't previously thought about the issue and need, now more than ever, to consider whether their product might be a combustible dust under foreseeable emergencies,” Howell told Bloomberg BNA Jan. 2.

Direct Knowledge, Alternatives

If a company knows that a product has been involved in a dust fire or explosion, the OSHA memo said, then it should classify the product as a combustible dust. The exception is if the company can show the conditions around the dust event didn't arise from expected use of the product or foreseeable emergencies.

Absent direct knowledge, the memo provides three other approaches that shippers can use to classify combustible dust hazards: laboratory tests, published results and particle size.

The OSHA memo pointed to testing methods described in ASTM International standards for establishing whether a material poses a combustible dust hazard.

In addition, the memo cited lists of test results for various materials published by the National Fire Protection Association, and includes online links to its own list and a database maintained by the Institute for Occupational Safety and Health of the German Social Accident Insurance system.

De Facto Definition?

Companies can use test data for similar materials if there isn't any data available for the substance that they are trying to classify for dust hazards, the memo said. Classification based on dust particle size—borrowed loosely from the consensus standard NFPA 6549—can be used when there is no test data or if the testing is inconclusive, the memo said. The memo appears to provide a de facto definition of combustible dust.

“If the material will burn and contains a sufficient concentration of particles 420 microns or smaller to create a fire or deflagration hazard, it should be classified as a combustible dust,” the memo said.
In a nod to more recent consensus standards, the memo said companies can use 500 microns as a threshold particle size.

Perpetuating a Problem

Marc Freedman, the U.S. Chamber of Commerce's executive director of labor law policy, said the memo perpetuates the problems that OSHA created by including combustible dust in the standard. Freedman told Bloomberg BNA Jan. 6 that the agency didn't allow for full stakeholder comment on that topic during the rulemaking process, which is especially problematic given that even defining combustible dust is a complex and contentious issue.

“At the end of the day, OSHA still doesn't have a definition of combustible dust, and employers are still expected to identify combustible dust hazards and train their employees accordingly,” Freedman said. “That's not appropriate. The way the memo reads, it is effectively implementing a non-OSHA, consensus organization's definition without the benefit of rulemaking, without a feasibility analysis, economic analysis or examination of its effect on small business. That's not how it's supposed to be done.”

Downstream Processing

Freedman also took issue with the memo's explanation of a shipper's responsibility for predicting combustible dust hazards that could arise downstream after shipping, from normal use and foreseeable emergencies.

“ ‘Foreseeable emergencies'—that's a contradiction in terms,” he said. “An emergency by definition is not foreseeable.”

The consideration of combustible dust hazards arising from downstream processing is the area of the new hazard communication standard that people are struggling with the most, said Denese Deeds, senior consultant at Industrial Health & Safety Consultants Inc. It can be especially challenging for organic compounds like plastics, foods and wood that are not hazardous in the form that they're shipped in, but could generate combustible dust once they're processed, she told Bloomberg BNA Jan. 6.

Deeds said that although the OSHA memo doesn't directly address it, there doesn't seem to be anything preventing a company from adding further explanation in the body of the safety data sheet saying that the combustible dust is generated during processing.

“It does seem odd to look at a solid material and think that you're looking at a combustible dust hazard,” Deeds said.

To contact the reporter on this story: Robert Iafolla in Washington at riafolla@bna.com
To contact the editor responsible for this story: Jim Stimson at jstimson@bna.com
The OSHA memo on classifying combustible dust hazards is available at http://tinyurl.com/lpyod9n.

Thursday, January 9, 2014

Dangers of Wood Pellet Plants | Inherently Safer Design

Excellent article below from our friends at The Harrington Group, LLC

But first, I want to make a few comments about safe design of these pellet plants:

Here in general terms are current best practices for wood pellet mills based on NFPA 664 and over 3 decades of experience protecting wood, sawdust and wood flour processes.

As a primary consideration, understand that these wood pellet plants are making fuel, that plant operations and maintenance personnel are constantly working around fuel. Consider wood flour as dangerous as gasoline. Utilize inherently safer equipment and process design. Separate, segregate and isolate various hazardous processes and equipment from each other.

Risk is defined as probability of occurrence and severity of consequence. You will want to design in various layered engineering controls to reduce risk of probability of occurrence as well as severity of consequences in pellet mill processes.

We reduce risk by reducing probability of occurrence by designing in fire prevention technology and systems. Then reduce consequences by designing in fire and explosion protection systems.

Do a process hazard risk analysis and you will find that primary ignition sources of fires are the dryers, hammermills, and pellet mills. There are of course additional secondary ignition sources. The primary areas of dust cloud explosions are the bins, coolers, dust collectors and silos.

You will want to add layers of fire and explosion prevention and protection.

The primary prevention control technology to reduce probability of fire is to utilize spark detection and extinguishing systems after all spark sources, in all ducts and conveyors with a fire hazard, and prior to all enclosures with explosion hazard, as well as black body/hot particle detection in transfer points with fire and/or explosion hazard.

The second layer of protection is to design in automatic sprinkler and deluge systems, as well as manual deluge in each process conveyor or bin with a fire hazard.

The third level or layer of protection is to add explosion protection systems utilizing venting, isolation and suppression on all conveyors, elevators, bins and silos with an explosion hazard.

Additional levels of protection should also be considered, especially CO or combustion gas detection and inerting in the silos, and bins. Other possible layers of prevention and protection include not only spark, ember and hot particle detection and suppression, but also heat, temperature, flame detection, smoke detection; and bearing temperature, run time, and belt alignment monitoring among others.

Consider that every time the product is moved or manipulated, combustible dust called fines are created. These fines can migrate around and settle in various locations around the plant. The lighter the dust, the higher it will settle. Housekeeping is of primary consideration to preventing explosions, so also consider central vacuum systems and oscillating fans to help control dust.

This is your base level hazard mitigation strategy and systems for pellet mills.

_Jeff Nichols


Fire Protection Consultants: Dangers of Wood Pellet Plants 
Harrington Group, Inc.

The Dangers of Wood Pellet Plant Facilities

 

Posted on Thursday, January 9th, 2014

Photo: Frieda Squires/The Providence Journal

An explosion occurred on August 20, 2013 at Inferno Pellets Co. in East Providence, Rhode Island and the resulting fire, which spread throughout most of the 300,000 square-foot factory, took about four hours for firefighters to bring under control. One employee was injured by the explosion and subsequently released from Rhode Island Hospital after being treated for first and second degree burns.

In September 2013, another wood pellet incident was reported. This time, a dust explosion occurred at the Nature’s Flame facility in Rotoakawa, New Zealand. Also in September, an explosion incident was reported at the Anderson Hardwoods Pellet facility in Louisville, Kentucky, where at least one person was taken to the hospital with injuries.

Going back a little further, on October 20, 2011, an explosion and fire occurred at the New England Wood Pellet facility in Jaffrey, New Hampshire, which originated in the facility’s dust conveyor system. The large ensuing fire took approximately 14 hours to extinguish by over 100 firefighters from 14 different departments. OSHA was brought in to investigate the incident, which resulted in the company being fined a total of $147,000 for safety violations including, “poor dust collection system design” and “no explosion prevention / protection”.

In June of 2011, a dust explosion and resulting fire knocked down operations for a month at the Georgia Biomass facility near Waycross, Georgia, one of the world’s largest wood pellet manufacturing facilities. The $175 million plant had only been open for about a month when the incident occurred. According to plant manager, Ken Ciarletta, an investigation cited an overheated roller/bearing assembly in a pelletizer as the likely ignition source.

Clearly, the process of manufacturing wood pellets involves all the right ingredients for explosions and fires to occur with a concerning frequency the potential to cause serious injuries, damage to property, and interruption of production.

What are Wood Pellets and Biomass Fuels?
For many years, wood pellets were referred to as, well, “wood pellets”.  Recently, wood pellets are being referred to as one form of a broader category known as biomass fuels. The term biomass refers to materials that have originated from living, or recently living, organisms. Most often, it refers to plant material. Biomass, including wood, can be used directly (through combustion) or indirectly to create heat and electricity. In order to use biomass indirectly to create heat or electricity, it must first be converted into some form of biofuel. There are various types of biomass fuels, or biofuels; however wood pellets are the most common type, and are generally made from compacted sawdust.

Wood pellets and other biofuels are considered to sustainable.  Reportedly, they can help to reduce reliance on fossil fuels, like oil, to produce heat and energy. Because of this, the industry is expected to boom in the upcoming years. As the manufacturing of wood pellets grows to meet demand, it is fair to predict that the number of explosions and fires will increase in direct proportion.
Stay tuned for part two of this series: Fire Prevention Tips for Wood Pellet Plants.

By Jeff Harrington, CEO and Founder of Harrington Group, Inc.