Page 24 - OHS, January/February 2022

COMBUSTIBLE DUST
Combustible Dust Insights Help Shape Training and Education
To help professionals and practitioners in various industries safely manage pesky particles, NFPA has developed six standards.
EBY CATHY LONGLEY
arlier this year, after an industrial manufacturing explosion in Singapore killed three and injured
1 seven more, NFPA Journal put
out a timely piece entitled Dust Disaster2 and an NFPA Learn Something New video that answered the question, “What is a Combustible Dust Explosion?”3
Speaking to NFPA Associate Editor Angelo Verzoni, Alexander Ing, one of the Association’s hazardous chemicals engineers, explained that combustible dusts are created when finely divided solids are turned into smaller pieces. We see this with metal manufacturing where chipping and grinding are commonplace, chemical processing plants when raw materials are turned into plastics and during agricultural manufacturing when grain or products are often converted into a flour or powder, as was the case in Singapore.
Ing pointed to the dust explosion pentagon, which is an expansion of the fire triangle as it relates to dust to set the stage for what might have happened in that February incident. The fire triangle starts with fuel, oxygen and an ignition source. If the three elements are present at the same time, you can get a fire. For example, if a pile of potato starch is exposed to a sufficient ignition source, fire can erupt on the top of that pile because that is where the surface area of the potato starch interacts with oxygen and all three elements of the fire triangle are present. If that same pile is dispersed into the air, a flash fire can be started from it. And, if that pile is dispersed in an enclosed space, that is considered confinement, which allows pressure to build as the gases rapidly expand during the reaction. So, a dust fire can occur if the three elements of the fire triangle—fuel, oxygen and an ignition source—are present and an explosion can occur if you add dispersion and confinement to the three elements of the fire triangle.
So, how common are combustible dust incidents? According to the 2021 Mid- Year Combustible Dust Incident Report4
generated by Dust Safety Science, there were 51 fires and 28 explosions reported globally in the first six months of the year. These incidents caused 44 injuries and eight fatalities, with two incidents causing more than $1 million in losses. The data shows that wood processing, wood products, agricultural activity and food production typically make up a large portion of the overall fire and explosion incidents, but from January through June this year, the “other” category of industries made up 45 percent of the injuries and 37 percent of the fatalities reported. Other settings include facilities that deal with pulp, paper or ethanol, and include places like high schools and educational facilities.
A running tally of recent incidents on the Dust Safety Science site indicates that there were 12 fires or explosions around the world in October alone. These incidents wrought varying degrees of havoc on facilities and resulted in employees being evacuated, response resources being called in, water supplies being tapped, operations coming to a halt and export schedules being affected.
To help professionals and practitioners in various industries safely manage pesky particles, NFPA has developed six standards—one that covers the fundamentals of combustible dust and five more addressing commodity-based considerations:
■ NFPA 652, Standard on the Fundamentals of Combustible Dust,5 which lays out the basics of things that are common throughout the dust world
■ NFPA 654, Standard for the Prevention of Fire and Dust Explosions from the Manufacturing, Processing, and Handling of Combustible Particulate Solids,6 which generally handles chemical dusts
■ NFPA 61, Standard for the Prevention of Fires and Dust Explosions in Agricultural and Food Processing Facilities,7 which generally handles agricultural and food dusts
Combustible Metals,8 which generally handles combustible metals
■ NFPA 664, Standard for the Prevention of Fires and Explosions in Wood Processing and Woodworking Facilities,9 which generally handles wood dust
■ NFPA 655, Standard for Prevention of Sulfur Fires and Explosions, which handles the size reduction and handling of sulfur10
This fall, a new training program also debuted. It applies the guidance found within the 2019 edition of NFPA 652. NFPA tapped into an expert training advisory group to glean specialized industrial knowledge and input for the training that is set in a grain mill. The three modules cover different forms of dust, proactive preventative measures to be taken to reduce risk and the impact that compliance has on protecting people and property. Completion of a dust hazard
www.ohsonline.com
■NFPA 484, Standard for 20 Occupational Health & Safety | JANUARY/FEBRUARY 2022
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