Combustible Dust FAQ
- What NFPA Codes are applicable to Combustible Dust?
| NFPA Number | Title | Current Edition |
|---|---|---|
| 61 | Standard for the Prevention of Fires and Dust Explosions in Agricultural and Food Processing Facilities | 2002 |
| 68 | Guide for Venting of Deflagrations | 2002 |
| 69 | Standard on Explosion Prevention Systems | 2002 |
| 70 | National Electrical Code | 2005 |
| 77 | Recommended Practice on Static Electricity | 2000 |
| 85 | Boiler and Combustion Systems Hazards Code | 2007 |
| 86 | Standard for Ovens and Furnaces | 2007 |
| 91 | Standard for Exhaust Systems for Air Conveying of Vapors, Gases, Mists, and Noncombustible Particulate Solids | 2004 |
| 484 | Standard for Combustible Metals | 2006 |
| 499 | Recommended Practice for the Classification of Combustible Dusts and of Hazardous (Classified) Locations for Electrical Installations in Chemical Process Areas | 2004 |
| 654 | Standard for the Prevention of Fire and Dust Explosions from the Manufacturing, Processing, and Handling of Combustible Particulate Solids | 2006 |
| 655 | Standard for Prevention of Sulfur Fires and Explosions | 2007 |
| 664 | Standard for the Prevention of Fires and Explosions in Wood Processing and Woodworking Facilities | 2007 |
- How does the NFPA define Combustible Dust?
- According to NFPA 654 “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.”
- What is DEFLAGRATION?
- According to NFPA 654, 3.3.7 “Propagation of combustion zone at a volictiy that is less than the speed of sound in the un-reacted medium.”
- What are the necessary conditions for Dust Deflagration?
- Combustible particulate solid small enough to be deflagrable.
- Deflagrable particle suspended in air.
- Deflagrable particulate of high enough concentration.
- Adequate igniter.
- What are Combustible Particulate Solids (CPS)?
- Any combustible solid material with a distinct particles or pieces. They can include fibers, chips, fines, dusts, and flakes.
- How small does a particulate need to be for a dust explosion?
- The smaller the particle size the more dangerous the particulate and greater likelihood of explosion.
- Where do you generally find the finest, which are more hazardous, accumulations of particulate in a building?
- Typically in the Highest compartments of buildings, such as rafters, top of ductwork, top of lights, etc.
- When does ignition occur?
- When sufficient energy per unit (temperature) of time and volume is applied to a suspended deflagrable particle.
- What is the one most important factor to mitigate the risk of a dust explosion?
- Limiting, or eliminating accumulated fugitive dust in the workplace.
- How much of the Floor Area in a typical Industrial Plant does the Surface area of Top of Ductwork, Conduit, Rafters, and all high surfaces account for?
- Rough calculations show that the available surface area of bar joists is approximately 5 % of the floor area and the equivalent surface area for steel beams can be as high as 10%.
- What is the Minimum Explosible Concentration (MEC)?
- The minimum concentration that will propagate a flame front through a suspension of the particulate in air or other medium of concern.”
- What industries may have Combustible Dusts?
| SICS | Industry | NAICS |
|---|---|---|
| 0723 | Crop Preparation Services for Market, Except Cotton Ginning | 115114, 115111 |
| 2052 | Fresh cookies, crackers, pretzels, and similar “dry” bakery products. | 311821 |
| 2062 | Refining purchased raw cane sugar and sugar syrup. | 311312 |
| 2087 | Flavoring extracts, syrups, powders, and related products, not elsewhere classified. | 311930 |
| 2099 | Prepared foods and miscellaneous food specialties, not elsewhere classified. | 311212 |
| 2221 | Broadwoven Fabric Mills, Manmade Fiber and Silk | 313210 |
| 2262 | Finishers of Broadwoven Fabrics of Manmade Fiber and Silk | 313311 |
| 2299 | Textile Goods, Not Elsewhere Classified | 313111 |
| 2421 | Sawmills and Planing Mills, General | 321113 |
| 2431 | Millwork | 321911 |
| 2434 | Wood Kitchen Cabinets | 33711 |
| 2439 | Structural Wood Members, Not Elsewhere Classified | 321213, 321214 |
| 2452 | Prefabricated Wood Buildings and Components | 321992 |
| 2493 | Reconstituted Wood Products | 321219 |
| 2499 | Wood Products, Not Elsewhere Classified | 321920, 321219 |
| 2511 | Wood Household Furniture, Except Upholstered | 337122 |
| 2591 | Drapery Hardware and Window Blinds and Shades | 337920 |
| 2819 | Industrial Inorganic Chemicals, Not Elsewhere Classified | 325188, 325998, 331311 |
| 2821 | Plastic Materials, Synthetic Resins, and Nonvulcanizable Elastomers | 325211 |
| 2823 | Cellulosic Manmade Fibers | 325221 |
| 2834 | Pharmaceutical Preparations | 325412 |
| 2841 | Soap and Other Detergents, Except Specialty Cleaners | 325611 |
| 2851 | Paints, Varnishes, Lacquers, Enamels, and Allied Products | 32551 |
| 2861 | Gum and Wood Chemicals | 325191 |
| 2899 | Chemicals and Chemical Preparations, Not Elsewhere Classified | 325510, 325998 |
| 3011 | Tires And Inner Tubes | 326211 |
| 3061 | Molded, Extruded, and Lathe-Cut Mechanical Rubber Goods | 326291 |
| 3069 | Fabricated Rubber Products, Not Elsewhere Classified | 326299 |
| 3081 | Unsupported Plastics Film and Sheet | 326113 |
| 3082 | Unsupported Plastics Profile Shapes | 326121 |
| 3086 | Plastics Foam Products | 326140, 326150 |
| 3087 | Custom Compounding of Purchased Plastics Resins | 325991 |
| 3089 | Plastics Products, Not Elsewhere Classified | 326199 |
| 3291 | Abrasive Products | 327910 |
| 3313 | Alumina and Aluminum Production and Processing | 331312 |
| 3334 | Primary Production of Aluminum | 331312 |
| 3341 | Secondary Smelting and Refining of Nonferrous Metals | 331314 |
| 3354 | Aluminum Extruded Products | 331316 |
| 3363 | Aluminum Die-Castings | 331521 |
| 3365 | Aluminum Foundries | 331524 |
| 3369 | Nonferrous Foundries, Except Aluminum and Copper | 331528 |
| 3398 | Metal Heat Treating | 332811 |
| 3441 | Metal Cans | 332431 |
| 3469 | Metal Stampings, Not Elsewhere Classified | 332116 |
| 3471 | Electroplating, Plating, Polishing, Anodizing, and Coloring | 332813 |
| 3479 | Coating, Engraving, and Allied Services, Not Elsewhere Classified | 332812 |
| 3496 | Miscellaneous Fabricated Wire Products | 332618 |
| 3499 | Fabricated Metal Products, Not Elsewhere Classified | 332999 |
| 3548 | Lighting Equipment, Not Elsewhere Classified | 335129 |
| 3644 | Noncurrent-Carrying Wiring Devices | 335932 |
| 3714 | Motor Vehicle Parts and Accessories | 336322 |
| 3761 | Guided Missiles and Space Vehicles | 336414 |
| 3799 | Transportation Equipment, Not Elsewhere Classified | 333924 |
| 3995 | Burial Caskets | 339995 |
| 3999 | Manufacturing Industries, Not Elsewhere Classified | 321999, 325998, 326199 |
| 4221 | Farm product warehousing and storage | 493130 |
| 4911 | Electric Services Establishments engaged in the generation, transmission, and/or distribution of electric energy for sale. | 221112 |
| 4952 | Sanitary treatment facilities. | 221320 |
| 4953 | Refuse Systems | 562920 |
| 5093 | Scrap and waste materials | 423930 |
| 5162 | Plastics materials and basic forms and shapes | 424610 |