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Managing Combustible Dust in Manufacturing - My Experience in Ontario Paul Bozek, PEng CIH ROH RT 215 Managing and Regulating Combustible Dust.

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Presentation on theme: "Managing Combustible Dust in Manufacturing - My Experience in Ontario Paul Bozek, PEng CIH ROH RT 215 Managing and Regulating Combustible Dust."— Presentation transcript:

1 Managing Combustible Dust in Manufacturing - My Experience in Ontario Paul Bozek, PEng CIH ROH RT 215 Managing and Regulating Combustible Dust

2 Outline Definition of “Combustible” Dusts Typical hazardous processes Typical controls and Issues (examples) Regulatory Requirements/Guidelines and Programs to manage the risk

3 Manufacturing Sites TypeTypical Combustible Dusts Food and BeverageSugar, Cocoa, Flours, Starch, hops, grains PharmaceuticalsActives, fillers/additives PlasticsPolymer powders and granules Recycling/E-waste handling many Not a comprehensive list, just example industries

4 Definition of “Combustible Dust” [P max x (dP/dt) max ] 2 Explosion Severity = (>0.5) [P max x (dP/dt) max ] 1 [MIT x MIE x MEC] 1 Ignition Sensitivity = (>0.2) [MIT x MIE x MEC] 2 1 = Pitt Coal 2 = Subject Dust

5 Definition of “Combustible Dust” – “…..presents risk of fire or deflagration hazard when suspended in air…. – Definition used to include, “<420 microns” – Good Aspects Not “normally present” suspended in occupied workspaces Min Explosive Conc. often 1000x OEL

6 Definition of “Combustible Dust” Problems: (in Hazard Identification) – Parameters are size dependent! “ as is” testing vs “sieve <420 microns” – Full testing is expensive ($3,000+) Testing for K ST alone gives only (dp/dt) max – Moisture content, fat content affect results – MSDS’s often silent or misleading “as is” product may be too large to be combustible but may contain fines that are combustible

7 Typical “Settled Dust” Hazards Re-suspended Dust hazard – requires Electrical “Hazardous Location” (Class 2 Division 1 or 2).

8 “Settled Dust” Hazard Control Positive press? Maintenance Ignition Controls Documented Cleaning Schedule

9 Typical Hazardous Processes (Explosions Inside Equipment) – Silo and Container Filling – Pneumatic conveying – “Air Material Separators” Dust Collectors Cyclones – Size reduction processes (eg grinding) – Sieving, Blending – Drying (eg fluidized bed)

10 Control: Explosion Venting Vents may be needed in ducts or piping Fireball hazard – Size? Where? Alternately, “suppression”

11 Dust Collector :Explosion Vent - Locations Vent duct to outdoors “Flameless” Vent

12 Dust Collector – Air Discharge Location? Directly Outside or Inside + secondary filter + “Hazloc”

13 Electrical “Hazardous Locations” Drawing stamped by P.Eng Elec equipment specs meet “Hazloc” classification? Installation inspected by Electrical Authority? Lift trucks rated for Hazloc?

14 Issues: Static Bonding OK?

15 Issues: Plastic Containers/Liners Size matters – static can build-up on containers or in bulk powders during transfer

16 Combustible Dust Policy/Programs – Identify, Assess Risk, Control Recognizing its’ presence historically a problem – Scope of Program Requirements OH&S Act, Fire Codes, many best practice guides (NFPA) – Change Management A good time to review compliance/conformance In Ontario, “Pre-Start H&S Review” requirements have triggered good project-based reviews

17 Ontario: “Pre-Start H&S Review” Report Requirements – Legally required when new or modified processes “process involves a risk of ignition or explosion that creates a condition of imminent hazard to a person’s health or safety” “use of a dust collector involves a risk of ignition or explosion” – Guidelines from Ministry and PEO for P.Eng Scope of report goes well beyond strict compliance Includes NFPA 68, 69, 499, 505 & ACGIH Ind Vent.

18 Thank You! – Acknowledgement: Paul Bozek, PEng CIH ROH RT 215 Managing and Regulating Combustible Dust


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