Combustible Dust Course for Die Casting Industry Employees - PowerPoint PPT Presentation

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Combustible Dust Course for Die Casting Industry Employees

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  1. NADCA North American Die Casting Association Combustible Dust Course for Die Casting Industry Employees Preventing Dust Explosions and Fires Protecting Employees from the Effects of Dust Explosions and Fires

  2. NADCA North American Die Casting Association Unit 1 Preventing Dust Explosions and Fires in the Die Casting Industry Unit 2 Protecting Employees from the Effects of Dust Explosions and Fires in the Die Casting Industry Unit 3 Unit 4

  3. Finely Divided Solid Particles • Introductions • Class Schedule • Instructions Are Known to Explode

  4. Terminal objectives for this Course Upon completion of this course students should be able to: 1. Explain how the materials used in die casting facilities may cause dust explosions and fires, the consequences of these events and how they may be prevented and mitigated. 2. Implement the work practices and procedures that will keep employees in the die casting industry safe from the hazards of dust explosions and fire. Alloy dusts explode!

  5. NADCA North American Die Casting Association Preventing Dust Explosions and Fires in the Die Casting Industry Unit 1

  6. Enabling Objectives Students should be able to: Discuss dust explosions and fires as a significant safety problem that may affect them; Explain how these events occur and how they may have catastrophic consequences to employees themselves and to the die casting plant; and, Identify the materials used in die casting that may cause dust explosions and/or fires and how they may be prevented or reduced in severity if they occur. Metal Dust Collector - Exploded and Collapsed

  7. This presentation is based on “Combustible Dust in Industry. . .” - OSHA Safety and Health Information Bulletin (SHIB 07-31-2005) (download at http://www.osha.gov/dts/shib/index.html ) NFPA 484 “Standard for Combustible Metals”, 2009 Ed.    (on-line free viewing at http://www.nfpa.org/aboutthecodes/list_of_codes_and_standards.asp )

  8. Combustible Dust Explosions

  9. Background • This section describes a series of horrific dust explosions that have occurred recently. • The US Chemical Safety and Accident Investigation Board (CSB) and OSHA have identified these explosions as representative of a national safety problem. • The list includes a spectacular metal dust explosion and fire in Indiana that killed one and injured one employee.

  10. Background • Organic Dust Fires and Explosions: • Massachusetts • (3 killed, 9 injured) • North Carolina • (6 killed, 38 injured) • Kentucky • (7 killed, 37 injured Metal Dust Fire and Explosion: Indiana (1 killed,1 injured) Recent Sugar Dust Explosion

  11. Common Causal Factors • Housekeeping to control dust accumulations unacceptable; • Ventilation system design flaws; • Lack of Hazard Assessment; • Lack of explosion prevention and mitigation.

  12. Phenol formaldehyde resin polyethylene dust Aluminum

  13. Imperial Sugar Company Port Wentworth GA Explosion and Fire February 7, 2008 14 Deaths and Numerous serious injuries

  14. US Chemical Safety and Hazard Investigation Board Photo

  15. 19:15:38 US Chemical Safety and Hazard Investigation Board Photo

  16. 19:15:41 US Chemical Safety and Hazard Investigation Board Photo

  17. 19:15:46 US Chemical Safety and Hazard Investigation Board Photo

  18. 19:15:55 US Chemical Safety and Hazard Investigation Board Photo

  19. US Chemical Safety Board • Found a pattern of catastrophic dust explosions • Recommended that OSHA take action • MSDS sheets often fail to provide dust explosion information

  20. OSHA INSTRUCTION U.S. DEPARTMENT OF LABOR Occupational Safety and Health Administration DIRECTIVE NUMBER: CPL 03-00-008 EFFECTIVE DATE: March 11, 2008 SUBJECT: Combustible Dust National Emphasis Program OSHA inspectors are to go out and inspect facilities across the US.

  21. With confinement there is an explosion Dust Explosion Requirements • Dust is combustible. • It must be dispersed in air or another oxidant, and • The concentration is at or above the minimum explosible concentration (MEC). • There is an ignition source, such as • an electrostatic discharge, • - spark, • - glowing ember, • - hot surface, • - friction heat, or • - a flame • that can ignite the dispersed combustible mixture

  22. Dust explosion in a work area Dust Dust settles on flat surfaces Some event disturbs the settled dust into a cloud Dust cloud is ignited and explodes Adapted from CSB

  23. Dust explosion in equipment Dust collector venting flame jet

  24. Dust explosion in equipment Dust Collector Dust explosion in equipment With dispersal and ignition of 2 kg dust by the flame jet

  25. Dust explosions • An initial (primary) explosion in • processing equipment or in an areawhere fugitive dust has accumulated: • may shake loose more accumulated dust; or, • damage a containment system (such as a duct, vessel, or collector). • The additional dust dispersed into the air may causeone or more secondary explosions. • These can befar more destructivethan a primary explosion.

  26. A Dust Explosion Event 0 25 50 75 100 125 150 175 200 225 250 300 325 Primary deflagration inside process equipment Time, msec. (Timing of actual events may vary)

  27. A Dust Explosion Event Shock wave caused by primary deflagration 0 25 50 75 100 125 150 175 200 225 250 300 325 Time, msec.

  28. A Dust Explosion Event 0 25 50 75 100 125 150 175 200 225 250 300 325 Time, msec. Shock waves reflected by surfaces within the building cause accumulated dust to go into suspension

  29. A Dust Explosion Event 0 25 50 75 100 125 150 175 200 225 250 300 325 Time, msec. Dust clouds thrown in the air by the shock waves

  30. A Dust Explosion Event 0 25 50 75 100 125 150 175 200 225 250 300 325 Time, msec. Primary deflagration breaks out of the equipment enclosure - creating a source of ignition

  31. A Dust Explosion Event 0 25 50 75 100 125 150 175 200 225 250 300 325 Time, msec. Secondary deflagration ignited

  32. A Dust Explosion Event 0 25 50 75 100 125 150 175 200 225 250 300 325 Time, msec. Secondary Deflagration is propagated through the dust clouds

  33. 0 25 50 75 100 125 150 175 200 225 250 300 325 Time, msec. Secondary deflagration bursts from the building

  34. A Dust Explosion Event 0 25 50 75 100 125 150 175 200 225 250 300 325 Time, msec. Collapsed building with remaining fires Adapted from OSHA diagrams prepared by John M. Cholin, P.E., FSFPE, J.M. Cholin Consultants, Inc.

  35. Combustible dust explosion hazard may exist in a variety of industries • dyes, • coal, • metals (e.g., aluminum, chromium, iron, magnesium, and zinc), and • fossil fuel power generation. • food (e.g., candy, starch, flour, feed), • plastics, • wood, • rubber, • furniture, • textiles, • pesticides, • pharmaceuticals,

  36. Dust Explosion Hazard “. . .any industrial process that reduces a combustible material and some normally noncombustible materials • to a finely divided state • presents a potential for a serious fire or explosion.” (NFPA’s Industrial Fire Hazards Handbook)

  37. Combustible Dust Explosions • Practice Quiz • 1. A combustible dust explosion or deflagration may occur when combustible dust, an ignition source, air or other oxidant, ______________ are present. • Dispersion of the dust • B. Confinement • C. A. and B. above • D. None of the above • 2. Combustible dust explosion hazards frequently exist in which of the following industrial activities? • A. Collecting beach and lake bottom sand • B. Mixing cement • C. Manufacturing and finishing magnesium and aluminum alloy castings. • D. All of the above

  38. Combustible Dust Explosions • Practice Quiz • 3. A combustible dust explosion in a piece of equipment or area where dust has accumulated: • May shake loose more accumulated dust • B. Damage a containment system • C. Cause one or more destructive secondary explosions • D. All of the above

  39. Combustible Dust Explosions • Practice Quiz • 1. A combustible dust explosion or deflagration may occur when combustible dust, an ignition source, air or other oxidant, ______________ are present. • Dispersion of the dust • B. Confinement • C. A. and B. above • D. None of the above • 2. Combustible dust explosion hazards frequently exist in which of the following industrial activities? • A. Collecting beach and lake bottom sand • B. Mixing cement • C. Manufacturing and finishing magnesium and aluminum alloy castings. • D. All of the above

  40. Combustible Dust Explosions • Practice Quiz • 3. A combustible dust explosion in a piece of equipment or area where dust has accumulated: • May shake loose more accumulated dust • B. Damage a containment system • C. Cause one or more destructive secondary explosions • D. All of the above

  41. Combustible Dust Explosions • In this section, we described a series of horrific dust explosions that have occurred recently. • Common causes were identified • How the explosions occurred was outlined • The factors needed to produce an explosion and the explosion process was discussed in detail.

  42. Particles • In this section, particles that participate in the explosion process are discussed. • Their characteristics are identified. • How they form in an industrial process is outlined Metal Dust Particles

  43. Particles Size • Pellets > 2mm diameter • Granules 0.42mm - 2mm • dust particles < 0.42mm (420μm) Hazard increases as particle size decreases • larger surface area for combustion • Fine particles may have a larger role in dust cloud ignition and explosion propagation.

  44. Particle Size of Common Materials Source: OSHA and Filtercorp International Ltd.

  45. may break into or This Particles Dusts may occur in the process stream and cause a hazard, regardless of starting particle size of the material

  46. Particles • Practice Quiz • 1. Regarding combustible dust particles – grinding and polishing waste: • A. Hazard decreases as particle size increases • B. Hazard increases as particle size decreases • C. They produce no hazard • D. None of the above • 2. Dusts may occur in the process stream and cause a hazard, regardless of starting particle size of the material : • True • False

  47. Particles • Practice Quiz • 1. Regarding combustible dust particles – grinding and polishing waste: • A. Hazard decreases as particle size increases • B. Hazard increases as particle size decreases • C. They produce no hazard • D. None of the above • 2. Dusts may occur in the process stream and cause a hazard, regardless of starting particle size of the material : • True • False

  48. Particles • In this section, particles that participate in the explosion process were discussed. • Their characteristics were identified. • How they form in an industrial process was outlined Metal Dust Particles

  49. Dust Hazard Analysis Couch Facility Analysis Components In this section, the various components of facility analysis are discussed. Several factors are identified as critical to the analysis: • Material combustibility; • Electrical classification; • Dust control; • Ignition control; and, • Damage control.

  50. Facility Analysis Components Carefully identify: • Materials that can be combustible when finely divided; • Processes which use, consume, or produce combustible dusts; • Open areas where combustible dusts may build up; • Hidden areas where combustible dusts may accumulate; • Means by which dust may be dispersed in the air; and • Potential ignition sources.