Combustible Dust National Emphasis Program

Transcription

1 Combustible Dust National Emphasis Program Ignition Source Dispersion Deflagration Explosion FIRE Confinement Combustible Dust Oxygen in Air/Oxidizers May 5,

2 Background History of Combustible Dust Incidents Overview of Combustible Dust NEP Resources 2

3 3 Catastrophic Combustible Dust Incidents since 1995

4 Combustible Dust Explosions History Malden Mills Methuen, MA December 11, Injured Nylon Fiber 4

5 5 Firefighting efforts following the explosion at Malden Mills (Methuen, Massachusetts, December 11, 1995).

6 Combustible Dust Explosions History Jahn Foundry Springfield, MA February 26, dead 9 Injured Phenolic resin dust 6

7 Combustible Dust Explosions History Ford River Rouge: Secondary Coal Dust Explosion February 1, 1999 Killed six workers and injured 36 7

8 Combustible Dust Explosions History May 16, 2002 Rouse Polymerics Vicksburg, MS 5 dead, 7 injured Rubber Dust 8

9 9 Combustible Dust Explosions History January 29, 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

10 West Pharmaceutical facility destroyed by polyethylene dust 10

11 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 11

12 12 Combustible Dust Explosions History October 29, 2003 Hayes Lemmerz Manufacturing Plant Two severely burned (one of the victims died) Accumulated aluminum dust Facility manufactured cast aluminum automotive wheels

13 Imperial Sugar Recent explosion Imperial Sugar Company Sugar refinery 13 killed; + 40 injured $8,777,500 in penalties 13

14 U-Tube Videos Sawdust Cannon Creamer cannon 14

15 Types of Dust Involved in incidents Coal 8% Inorganic 4% Other 7% Food 23% Plastic 14% Metal 20% Wood 24% 15

16 Types of Industries Involved in Dust Incidents Equipment Manufact'g. 7% Fabricated Metal Products 7% Electric Services 8% Rubber & Plastic Products 8% Furniture & Fixtures 4% Other 7% Primary Metal Industries 8% Food Products 24% Lumber/ Wood Products 15% Chemical Manufact'g. 12% 16

17 Dust Incidents, Injuries & Fatalities Not even close to being a complete summary of incidents Injuries / Fatalities Incidents Fatalities Injuries Incidents Figure 11. Dust incidents, injuries & fatalities, Source: CSB

18 Important Points Regarding the CSB Data According to the CSB, The combustible dust incidents the CSB lists from 1980 to 2005 are likely only a small sampling, as no federal or state agency keeps specific statistics on combustible dust incidents, nor does any single data source provide a comprehensive collection of these incidents. Information about small combustible dust incidents and near-misses is also generally unavailable. Incidents that cause no fatalities, significant injuries or major fires may not be recorded in the OSHA and fire incident databases The true extent of the problem is likely understated. Due to these limitations, the CSB does not represent the incident data as complete or error free and other compilations of dust explosion data are available. 18

19 What Combustible Dusts are explosible? Metal dust such as aluminum and magnesium Wood dust Coal and other carbon dusts Plastic dust Biosolids (dried wastes from sewage treatment plants) Organic dust such as sugar, paper, soap, grains and foodstuffs, and dried blood Certain textile materials 19

20 20 Which Industries have Potential Dust Explosion Hazards? Food products Agriculture Chemical Textile Forest and furniture products Metal Processing Paper products Pharmaceuticals Recycling operations (metal, paper, and plastic recycling operations.)

21 Definitions and Terminology 21 Combustible Dust Combustible Particulate Solid Hybrid Mixture Fugitive Grain Dust 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)

22 22 Definitions and Terminology What is Combustible Dust? 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.

23 Definitions and Terminology What is Combustible Dust? 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 23

24 Particle Size of Common Materials Common Material Size (microns) Table salt 100 White granulated sugar Sand 50+ Talcum (baby) powder 10 Mold spores Human hair Flour Source: Filtercorp International Ltd. 24

25 Definitions and Terminology Class II Locations those that are hazardous because of the presence of combustible dust. The following are Class II locations where the combustible dust atmospheres are present: Group E. Atmospheres containing combustible metal dusts, including aluminum, magnesium, and their commercial alloys, and other combustible dusts whose particle size, abrasiveness, and conductivity present similar hazards in the use of electrical equipment. 25

26 26 Definitions and Terminology Group F. Atmospheres containing combustible carbonaceous dusts that have more than 8 percent total entrapped volatiles as per ASTM D 3175 *, OR Those that have been sensitized by other materials so that they present an explosion hazard Coal, carbon black, charcoal, and coke dusts are examples of carbonaceous dusts. Group G. Atmospheres containing other combustible dusts, including flour, grain, wood flour, plastic and chemicals. * ASTM D 3175: Standard Test Method for Volatile Matter in the Analysis Sample of Coal and Coke (used for coal and coke dusts)

27 Definitions and Terminology 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 27

28 Definitions and Terminology How are MEC and LFL Different? Minimum Explosible Concentration (MEC): The minimum concentration of combustible dust suspended in air, measured in mass per unit volume that will support a deflagration. This is the proper technical term for dusts. Lower Flammable Limit (LFL): The lower flammable limit is the lowest concentration of a combustible substance in an oxidizing medium that will propagate a flame (vapors & gases). Upper Flammable Limit (UFL): The upper flammable limit is the highest concentration of a combustible substance in an oxidizing medium that will propagate a flame (vapors & gases). 28

29 Explosible Range IH Range Explosible Range Dust Deposit MASS OF POWDER/DUST PER UNIT VOLUME [g/m 3 ] 29 Source: Dust Explosions in the Process Industries, Second Edition, Rolf K Eckhoff

30 Definitions and Terminology Minimum Ignition Temperature (MIT). The lowest temperature at which ignition occurs. the Smaller the particle size the Lower the MIT the Lower the moisture content - the Lower the MIT Minimum Ignition Energy (MIE). The lowest electrostatic spark energy that is capable of igniting a dust cloud. Energy Units (millijoules) Decrease in particle size and moisture content decreases MIE An increase in temperature in dust cloud atmosphere decreases MIE 30

31 The Typical Explosion Event Initial Internal Deflagration Process Equipment Time, msec.

32 The Typical Explosion Event Initial Internal Deflagration Shock Wave Process Equipment Time, msec.

33 The Typical Explosion Event Initial Internal Deflagration Elastic Rebound Shock Waves Process Equipment Time, msec. 33

34 The Typical Explosion Event Initial Internal Deflagration Dust clouds caused by Elastic Rebound Process Equipment Time, msec. 34

35 The Typical Explosion Event Containment Failure from Initial Deflagration Dust Clouds Caused by Elastic Rebound Process Equipment Time, msec. 35

36 The Typical Explosion Event Dust Clouds Caused by Elastic Rebound Process Equipment Secondary Deflagration Initiated Time, msec.

37 The Typical Explosion Event Process Equipment Secondary Deflagration Propagates through Interior Time, msec.

38 The Typical Explosion Event Process Equipment Secondary Deflagration Vents from Structure Time, msec.

39 The Typical Explosion Event Secondary Deflagration Causes Collapse and Residual Fires Time, msec. Diagrams Courtesy of John M. Cholin, P.E., FSFPE, J.M. Cholin Consultants, Inc.

40 40 NEP/ Industry Application Food products Agriculture Chemicals Textiles Forest and furniture products Metal processing Tire and rubber manufacturing plants Paper products Pharmaceuticals Wastewater treatment Recycling operations (metal, paper, and plastic) Coal dust in coal handling and processing facilities

41 Other Programs State plan participation in this national emphasis effort is strongly encouraged but is not required Does not replace the grain handling facility directive, OSHA Instruction CPL , Inspection of Grain Handling Facilities, 29 CFR Not intended for inspections of explosives and pyrotechnics manufacturing facilities covered by the Process Safety Management (PSM) standard ( ) Does not exclude facilities that manufacture or handle other types of combustible dusts (such as ammonium perchlorate) covered under the PSM standard 41

42 Primary Applicable OSHA Standards General Housekeeping Hazardous (Classified) Locations Powered Industrial Trucks Bakery Equipment Sawmills Grain Handling General Duty Clause 42

43 43 Resources

44 44 Safety and Health Information Bulletin Purpose Background Elements of a Dust Explosion Facility Dust Hazard Assessment Dust Control Ignition Control Damage Control Training References

45 OSHA Outreach Materials PowerPoint Presentation SHIBs and TIBs Posters State program materials 45

46 NFPA Standards Dust Hazards 61 Agriculture 68 Deflagration Venting Systems 69 Explosion Prevention Systems 70 National Electric Code 77 Static Electricity 85 Boiler and Combustion Systems 86 Ovens and Furnaces 91 Exhaust Systems 46

47 NFPA Standards Electrical & Systems 484 Combustible Metals Includes Magnesium, Titanium, Zirconium, Aluminum, Tantalum and other reactive metals 499 Classification of Combustible Dust 654 manufacturing, Processing and Handling of Combustible Particulate Solids 655 Sulfur 664 Wood and more 47

48 Viewing NFPA Standards Point to Codes and Standards Click Document List Click on standard desired, NFPA XXX On bottom, click Preview this Document Below disclaimer, click I Agree Click Open NFPA XXX After standard opens, the button gives you the Table of Contents 48

49 Typical hazards Citations Accumulation of combustible dust in areas which have/may have ignition sources Lack of, or inadequate, explosion mitigation Failure to control ignition sources inside equipment Cleaning dust with non-explosion proof equipment (e.g., vacuums) 49

50 Citations Typical hazards (con t) Cleaning dust with compressed air (electrostatic issue) PPE Inadequate Ventilation HazCom training 50

51 51 Citations Other important standards HazCom Failure to train Inadequate MSDS Also a possible source of employer knowledge (a) Properly assess workplace hazards & provide Non-static clothing Flame retardant clothing Footwear

52 Citations Other important standards When dust is listed in Appendix A, can be cited in its entirety Possible citations if dust explosion hazard not evaluated in Process Hazard Analysis and could affect covered processes May lead to additional citations such as:»siting»training» Operating procedures, etc. 52

53 a) Scope: this section contains requirements for the control of grain dust fires and explosions, and certain other safety hazards associated with grain handling facilities. b) Application: grain elevators, feed mills, flour mills, rice mills, dust pelletizing plants, dry corn mills, soybean flaking operations, and the dry grinding operations of soycake. d) Emergency Action Plan: the employer shall develop and implement an emergency action plan meeting the requirements contained in

54 i) Contractors: the employer shall inform contractors performing work at the grain handling facility of known potential fire and explosion hazards related to the contractor s work and work area.and applicable safety rules of the facility. j) Housekeeping: the employer shall develop and implement a written housekeeping program that establishes the frequency and method(s) determined best to reduce accumulations of fugitive grain dust. Ledges, floors, equipment, and other exposed surfaces Priority housekeeping areas Floors within 35 of bucket elevators Floors of enclosed areas containing grinding equipment Floors of enclosed areas containing grain dryers located inside the facility. 54

55 j) (continued) Immediately remove any fugitive grain dust accumulations whenever they exceed 1/8 inch at priority housekeeping areas, pursuant to the housekeeping program, or shall demonstrate and assure, through the development and implementation of the housekeeping program, that equivalent protection is provided. Compressed air to blow dust from ledges, walls, and other areas shall only be permitted when all machinery that presents an ignition source in the area is shut-down, and all other known potential ignition sources in the area are removed or controlled. 55