How to Prevent a Combustible Dust Explosion

Are my facilities and employees protected from the dust hazards created from my manufacturing process? Is my dust flammable or combustible? Do I have the proper measures in place to prevent risky occurrences or manage my hazardous dust? If you are asking these questions, you are not alone. With OSHA tightening down on restrictions, NFPA continuously creating and updating guidelines and codes, insurance companies and local authorities having jurisdiction (AHJ) creating stronger mandates, all companies are looking for answers on how to properly deal with the safety concerns associated with process dust hazards.

What is combustible dust?

• NFPA 654 and 484 defines hazardous combustible dust as any finely divided material that is dispersed and can be ignited in air.
• Process dust that is generated in industries such as food, plastics, wood, pharmaceutical, rubber, metals and chemicals can be work environments that create flammable and explosive dust. Knowing your industry and dust generation process will be the starting point for identifying combustible dust.
• MSDS sheets can be helpful in identifying if your material is categorized as flammable or explosive
• Dust testing can be completed by an industrial/chemical process safety company. These tests are completed by providing a dust sample and combustible dust testing is completed identifying key items such as Explosion Severity (Kst, Pmax, dP/dtmax), Minimum Ignition Energy (MIE), Minimum Explosible Concentration (MEC), Minimum Autoignition Temperature of a Dust Cloud (MIT), Hot Surface Ignition Temperature of Dust Layers (LIT), Limiting Oxygen Concentration (LOC). The data collected from these tests will create a framework for which decisions such as general dust handling, dust collection, protection equipment selection, housekeeping standards and internal risk standards can be generated.

How to handle combustible dust?

• NFPA 654 provides extensive direction on handling of combustible material. Key items include :
  • Minimizing dust escape from manufacturing processes
  • Using properly designed dust collection systems, filters, and ducting to efficiently evacuate the process dust into a containment system
  • Create housekeeping standards that keep work environments and equipment clean from dust buildup
  • Regular inspection and cleaning of walls, joists, piping, hidden areas where explosive dust can build up.
  • Proper selection of cleaning equipment such as vacuum cleaners that can safely handle combustible dust.
• OSHA (29 CFR) outlines ventilation requirements which involves combustible dust and cleanliness standards.
• NFPA 654 and OSHA outline ignition control measures that must be taken to prevent explosions such as electrical guidelines, static electricity and bonding, open flame control, spark control and properly identifying hazardous areas and classifying them accordingly.

Dust Collection Systems and Protection Equipment Selection

• Once a dust hazard has been identified, a properly sized dust collection system is the crucial next step to provide protection for your employees, facility and getting under compliance for national or local codes. Pollution Control Systems specializes in dust collection and can assist in proper selection of equipment, design (CFM, conveying velocity, dust capture measures, duct design, filter selection) along with fire and explosion protection items that interface with the dust collector and ducting.
• Pollution Control Systems is a master distributor for Donaldson Torit dust collectors and Donaldson Torit continues to provide quality equipment to assist in most manufacturing dust collection need and supports combustible dust strategies that meet NFPA and OSHA codes.
• PCS provided, NFPA and OSHA approved ancillary equipment items:
  • Explosion Vents
  • Spark detection and/or mitigation
  • Fire protection, chemical or sprinkler
  • Explosion backdraft dampers
  • Chemical explosion isolation
  • Dust Collector discharge protection, airlock or drum assembly
  • Control Panel design for integration
• Contact Pollution Control Systems today and a representative will be happy to assist in any item related to combustible dust or equipment selection and design. Our goal is to ensure your dust control procedures are correct and efficient to allow the safest work environment possible.