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1 Combustible Dust National Emphasis Program Ignition Source March 25, 2010 Ignition Source Confinement Oxygen in Air/Oxidizers Dispersion Combustible Dust Deflagration Explosion FIRE
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2 Overview History of Combustible Dust Incidents Hazard Mitigation Techniques Combustible Dust NEP
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3 Catastrophic Combustible Dust Incidents since 1995
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4 Malden Mills Methuen, MA December 11, 1995 37 Injured Nylon Fiber Combustible Dust Explosions History
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5 Firefighting efforts following the explosion at Malden Mills (Methuen, Massachusetts, December 11, 1995).
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6 Combustible Dust Explosions History Jahn Foundry Springfield, MA February 26, 1999 3 dead 9 Injured Phenolic resin dust
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7 Combustible Dust Explosions History May 16, 2002 Rouse Polymerics Vicksburg, MS 5 dead, 7 injured Rubber Dust
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8 Combustible Dust Explosions History January 29, 2003 - West Pharmaceutical Services, Kinston, NC –Six deaths, dozens of injuries –Facility produced rubber stoppers and other products for medical use –Plastic powder accumulated above suspended ceiling ignited
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9 West Pharmaceutical facility destroyed by polyethylene dust
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10 Combustible Dust Explosions History February 20, 2003 – CTA Acoustics Corbin, KY –Seven Workers died –Facility produced fiberglass insulation for automotive industry –Resin accumulated in production area and was ignited
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11 http://www.csb.gov/co mpleted_investigation s/docs/CSBFinalRepo rtCTA.pdf
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12 Imperial Sugar Port Wentworth, Georgia 14Killed Many Hospitalized February 7, 2008 Sugar Involved
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13 Types of Dust Involved in incidents
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14 Types of Industries Involved in Dust Incidents
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15 Definitions and Terminology Combustible Dust Combustible Particulate Solid Hybrid Mixture Class II Locations Deflagration Detonation Explosion Minimum Explosible Concentration (MEC) Lower Flammable Limit (LFL) Upper Flammable Limit (UFL) Minimum Ignition Temperature (MIT) Minimum Ignition Energy (MIE)
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16 NFPA 654 (2006) Definitions Combustible dust. A combustible particulate solid that presents a fire or deflagration hazard when suspended in air or some other oxidizing medium over a range of concentrations, regardless of particle size or shape. Combustible Particulate Solid. Any combustible solid material composed of distinct particles or pieces, regardless of size, shape, or chemical composition. Hybrid Mixture. A mixture of a flammable gas with either a combustible dust or a combustible mist. What is Combustible Dust? Definitions and Terminology
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17 Definitions and Terminology NFPA 69 (2002), and 499 (2004) Definitions –Combustible Dust. Any finely divided solid material 420 microns or less in diameter (i.e., material passing through a U.S. No 40 Standard Sieve) that presents a fire or explosion hazard when dispersed 1 micron (µ) = 1.0 x 10 -6 m = 1.0 x 10 -4 cm = 1.0 x 10 -3 mm 420 µ = 420 x 10 -4 cm =.042 cm = 0.4mm A typical paper thickness is approximately 0.1mm What is Combustible Dust?
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18 Standard Sieve Sizes Sieve NumberSieve opening (µm) 40425 60250 80180 100150 20075 23063 32545 40038
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19 Particle Size of Common Materials
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20 Increase of Surface Area Surface Area Increases with increasing subdivision Figures Source: Dust Explosions in the Process Industries, Second Edition, Rolf K Eckhoff
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21 Combustion Rate Increase Combustion Rate Increases with Increasing Subdivision Slow Combustion Fast CombustionDeflagration/Explosion Source: Dust Explosions in the Process Industries, Second Edition, Rolf K Eckhoff
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22 Deflagration Vs. Explosion Deflagration. Propagation of a combustion zone at a speed that is less than the speed of sound in the unreacted medium. Detonation. Propagation of a combustion zone at a velocity that is greater than the speed of sound in the unreacted medium. Explosion. The bursting or rupture of an enclosure or a container due to the development of internal pressure from deflagration. Explosion Deflagration Detonation Definitions and Terminology
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23 Source: Dust Explosions in the Process Industries, Second Edition, Rolf K Eckhoff Explosible Range Dust Deposit Explosible Range IH Range 10 -3 10 -2 10 -1 11010 1 10 2 10 3 10 4 10 5 10 6 MASS OF POWDER/DUST PER UNIT VOLUME [g/m 3 ]
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24 Dust Fire/Explosion Combustible Dust Oxygen in Air Ignition Source Dispersion Confinement Explosion FIRE Deflagration
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25 The “Typical” Explosion Event Process Equipment Initial Internal Deflagration Time, msec. 0 25 50 75 100 125 150 175 200 225 250 300 325
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26 The “Typical” Explosion Event Process Equipment Initial Internal Deflagration Shock Wave Time, msec. 0 25 50 75 100 125 150 175 200 225 250 300 325
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27 The “Typical” Explosion Event Process Equipment Initial Internal Deflagration Elastic Rebound Shock Waves Time, msec. 0 25 50 75 100 125 150 175 200 225 250 300 325
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28 The “Typical” Explosion Event Time, msec. 0 25 50 75 100 125 150 175 200 225 250 300 325 Process Equipment Initial Internal Deflagration Dust clouds caused by Elastic Rebound
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29 The “Typical” Explosion Event Process Equipment Containment Failure from Initial Deflagration Dust Clouds Caused by Elastic Rebound Time, msec. 0 25 50 75 100 125 150 175 200 225 250 300 325
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30 The “Typical” Explosion Event Process Equipment Secondary Deflagration Initiated Dust Clouds Caused by Elastic Rebound Time, msec. 0 25 50 75 100 125 150 175 200 225 250 300 325
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31 The “Typical” Explosion Event Process Equipment Secondary Deflagration Propagates through Interior Time, msec. 0 25 50 75 100 125 150 175 200 225 250 300 325
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32 The “Typical” Explosion Event Process Equipment Secondary Deflagration Vents from Structure Time, msec. 0 25 50 75 100 125 150 175 200 225 250 300 325
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33 The “Typical” Explosion Event Secondary Deflagration Causes Collapse and Residual Fires Time, msec. 0 25 50 75 100 125 150 175 200 225 250 300 325 Diagrams Courtesy of John M. Cholin, P.E., FSFPE, J.M. Cholin Consultants, Inc.
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34 Hazard Mitigation
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35 Hazard Mitigation Dust control Ignition source control Explosion Prevention
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36 Dust Control Design of facility & process equipment Contain combustible dust Clean fugitive dust Regular program Access to hidden and overhead areas Safe cleaning methods
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37 Ignition Source Control Electrical equipment Static electricity control Mechanical sparks & friction Open flame control Design of heating systems & heated surfaces Use of tools, & vehicles
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38 Explosion Prevention Oxidant Concentration Reduction Deflagration Venting Deflagration Pressure Containment Deflagration Suppression Systems Isolation of equipment
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39 OSHA Standards/Citations Includes: Ventilation Standard Housekeeping Standard. Housekeeping in storage areas. Section 5(a)(1) (general duty clause) Housekeeping violations at coal-handling operations Personal Protective Equipment (PPE) Process Safety Management Electrical Powered Industrial Trucks Welding, cutting, and brazing Warning Signs Hazard communication Egress Fire protection
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40 Partial List of Relevant NFPA Standards NFPA Number Title 61Prevention of Fires and Dust Explosions In Agricultural and Food Products Facilities 68Venting of Deflagrations 69Explosion Protection Systems 70National Electrical Code 77Recommended Practice on Static Electricity 86Ovens and Furnaces 484Standard for Combustible Metals, Metal Powders, and Metal Dusts 499 Recommended Practice for the Classification of Combustible Dusts and Of Hazardous (Classified) Locations for Electrical Installations in Chemical Process Areas 654 Prevention of Fire and Dust Explosions From the Manufacturing, Processing, And Handling of Combustible Particulate Solids 664 Prevention of Fires and Explosions in Wood Processing and Woodworking Facilities
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41 Inspections Conducted
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42 Types of Industries Inspected by Percent
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43 Industries Inspected under NEP
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44 Total Violations Issued
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45 % Inspections In-Compliance (Insps W/O Violations & Closed)
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46 Combustible Dust Related Violations 234 439 151 232 388 88 171 55 193 0 100 200 300 400 500 600 700 5(a)(1) HazCom Fire Extinguishers Electrical (Haz Loc) House Keeping Compressed Air PPE First Aid Powered Industrial Trucks* *The number of violations pertaining to powered industrial trucks includes those that are combustible dust related (approved for class II locations) and other violations (e.g., training and other items covered under 1910.178).
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47 Combustible Dust Related Violations
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48 Some Combustible Dust NEP Findings 1.Hazardous levels of dust accumulations in the workplaces due to poor housekeeping practices. 2.Electrical equipment and Powered Industrial Trucks not approved for locations handling combustible dusts 3.Dust collectors were located inside buildings without proper explosion protection systems, such as explosion venting or explosion suppression systems. 4.Deflagration isolation systems were not provided to prevent deflagration propagation from dust handling equipment to other parts of the plant. 5.The rooms with excessive dust accumulations were not equipped with explosion relief venting distributed over the exterior walls and roofs of the buildings.
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49 Some Combustible Dust NEP Findings 6.The horizontal surfaces such as beams, ledges and screw conveyors at elevated surfaces were not minimized to prevent accumulation of dust on surfaces. 7.Air from the dust collector was recycled through ductwork back into the work area. 8.Magnetic separators and tramp metal separators were not installed or not functioning to prevent foreign material process stream and potentially cause a spark 9.Explosion vents on bucket elevatior(s) and dust collectors were directed into work areas and not vented to a safe, outside location away from platforms, means of egress, or other potentially occupied areas
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50 Some Combustible Dust NEP Findings 10.Equipment (such as grinders and shakers) were not maintained to minimize escape of dust into the surrounding work area. 11.Ductworks used in transporting combustible dust were not constructed of metal (conductive) and were not bonded or grounded to minimize generation and accumulation of static electricity. 12.Hot work (open flame or sparks from welding, cutting, grinding) was performed in the combustible dust handling areas without hot work procedures.
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51 Oct 1, 2007 – March 22, 2010 SIC 3089 Data Criteria SIC 3089 Total number of Inspections64 Total Violations Issued249 Avg. Number of Violations Issued Per Initial Inspection5.1 Percent Total Violations Cited As Serious66% Avg. Current Penalty Per Serious Violation$946
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52 1910.1200Hazard Communications -- 22 Violations 1910.147Lockout/Tagout -- 20 Violations 1910.212Machine Guarding – 20 Violations 1910.022Housekeeping – 16 Violations 1910.134Respiratory Protection -- 16 1910.305Electrical (Wiring Methods, Components and Equipment) -- 13 1910.217Mechanical Power Presses -- 12 5(a)(1)General Duty Clause – 11 Violations 1910.132Personal Protective Equipment -- 11 1910.219Mechanical Power Transmission -- 10 OSHA Standards Violated at Facilities with SIC 3089
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53 OSHA Training Over 350 compliance officers trained on PSM with combustible dust being a component 200 compliance officers have received specific combustible dust training Approximately 1400 state and federal compliance officers received webinar refresher training
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54 OSHA Compliance Assistance Resources: Combustible Dust Safety and Health Topics Page Fact Sheet Poster Safety and Health Information Bulletin (2005) OSHA’s Combustible Dust Poster
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55 Combustible Dusts Regulations Status?
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56 Questions?
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