DSS 004: Nova Scotia Dust Collector Safety Program and Explosion Safety with Jeramy Slaunwhite

In this episode of the Dust Safety Science podcast we discuss dust collector fire and explosion safety in wood working shops with Jeramy Slaunwhite, Explosion Safety Engineering Consultant with REMBE®, INC.

In this episode, Jeramy shares his extensive knowledge from material handling and ventilation systems, to government safety and education, and to evaluating fire and explosion hazards in industrial facilities. Jeramy has a rare background which covers a broad spectrum that gives him an interesting vantage point that is not typically available in the combustible dust safety community.

Nova Scotia Dust Collector Safety Program

In this episode we spend a good amount of time discussing the Nova Scotia Dust Collector Fire and Explosion Safety Program that Jeramy was a part of through various roles.

In this project an initial assessment demonstrated unsafe explosion venting from a dust collector at a recently built high-school in the province. This lead to a review of 15 schools in 2010. During this review, all 15 schools demonstrated fire and explosion deficiencies in the handling of combustible dust and needed to be updated. This lead to a province-wide review, audit, and updating, of dust collectors at all government owned buildings.

This province wide review resulted in about 150 technology and wood production labs at schools in the province being shut down from eight to 10 weeks while the dust collectors were evaluated for fire and explosion hazards. In addition to the school wood shop classes, Jeramy also worked on review of dust collectors in all government operated buildings which also demonstrated deficiencies.

Most Common Deficiencies

Based on the interview, the most common deficiencies from Jeramy’s memory included:

Incorrect explosion venting including absence of venting, venting to non-safe locations, undersized vents, and painted over vent panels or doors.
Incorrect dust collector location including collectors being indoors without explosion venting.
Absence of fire protection systems to reduce the severity of an incident.
Absent or under maintained back-flow preventers meant to stop an explosion from propagating back into the building.
Incorrect exhaust air systems without fire or explosion prevention methods.

Another difficulty that Jeramy mentions in wood shops, is not cleaning sawdust out of equipment such as saws, planers, and mills. He mentioned incidents where sawdust had completely covered the equipment motors causing them to heat up and catch fire. This is similar to the planner mill sawdust fires in New Brunswick discussed in the second episode of the podcast, further illustrating fire and explosion hazards in woodworking shops.

Dust Above Drop Ceilings – A Serious Explosion Hazard

In the interview Jeramy mentions that incorrect return air ducting and under maintained dust collector systems can lead to sawdust being deposited into drop ceilings above the classroom. This is a very dangerous situation in which a fire or explosion in the dust collector could lead to a catastrophic secondary explosion (for example see the West Pharmaceutical Services Dust Explosion and Fire Investigation Report from the US Chemical Safety Board).

In the introduction to the interview, I recommend that any facility handling combustible dust that has a drop ceiling, should check above it routinely for dust accumulation. This should be done when all machinery is turned off, so that a fire or explosion is not initiated. If any accumulation of dust is found (even one-quarter of an inch or more) there may be enough fuel to completely destroy the facility with a secondary explosion.

Conclusion

The breadth and wide-spread nature of the deficiencies in fire and explosion protection found in the Nova Scotia Dust Collector Safety program illustrates a potentially serious systematic issue across the province. Furthermore, this begs the question how many schools have incorrect protection throughout Canada or even throughout North America?

From January to June 2018, we recorded four notable wood dust/saw dust fires at high-schools and educational facilities in the United States (General McLane High School-PA, East Greenwich High School-RI, Mason High School-OH, and Dale Jackson Career Center-TX). As mentioned in the podcast episode, each of these incidents could of served to ignite a larger sawdust explosion under certain circumstances. If these dust collectors are not properly protected, the occupants of the wood shop classroom could be severally injured should an incident occur.