Dust Explosions

Exponent engineers offer services for the protection of life, property, business operation, and the environment from the harmful effects of combustible-dust fires and explosions. Our staff has extensive experience in the investigation of past combustible incidents, performing dust hazard analyses (DHAs), and the prevention and mitigation of future incidents.

Our services include:

  • Dust explosion origin, cause, and propagation analysis
  • Combustible-dust testing to evaluate the hazards of specific materials
  • Facility reviews and inspections for compliance with regulations, consensus standards, and best practices
  • Dust hazard analyses (DHAs) of new and existing facilities
  • Development of methods to mitigate dust explosion hazards
  • Evaluation of proposed and existing fire suppression and explosion protection systems
  • Analysis of performance-based design alternatives for facilities and dust-handling equipment
  • Code and engineering consulting for unique operations, equipment, and facilities
  • Evaluation of OSHA citations and proposed mitigation methods
  • Engineering evaluations of process risks and hazards associated with product flow, personal protective equipment, life safety and egress, fire suppression, standard operating procedures, maintenance and other process related issues.

The Prevalence of Dust


Many materials, ranging from baking flour to metal dusts, can fuel dust explosions when present in a finely divided state. Most materials that can burn or oxidize become a combustible dust explosion hazard when they are divided into small particles. Some materials are intentionally used in a powder or dust form in manufacturing, while other dusts are created as unintentional byproducts. Examples of materials that have historically caused dust fires or explosions include:

  • Coal
  • Cosmetics
  • Dyes
  • Grain and other agricultural products
  • Metals
  • Pharmaceuticals
  • Plastics and rubbers
  • Printer toner
  • Soaps
  • Textiles
  • Wood and paper

Addressing the Issue

Exponent inspects facilities that contain potentially combustible dusts, identifying areas where combustible-dust hazards may exist, and audits those areas for compliance with regulations, consensus standards, and best practices. Samples of material from different portions of facilities are typically collected, either by Exponent or the client, and the samples are tested at Exponent’s Combustible Dust Testing Laboratory. Standard ASTM testing methods and custom methods developed by Exponent are used to evaluate the fire and explosion hazard of materials.

Based on the measured hazard level, when appropriate, we assist the client in identifying mitigation techniques and applicable standards and regulations for the prevention of dust explosions, including standards developed by the National Fire Protection Association (NFPA). Exponent can also aid clients in evaluating proposals from equipment vendors to find cost-effective options to mitigate the hazards.

Familiarity with Regulations and Standards

Dust Regs

Exponent professionals track changes to federal and state regulations and enforcement practices. As part of the ongoing OSHA combustible-dust rulemaking process, Exponent engineers have attended stakeholder meetings and expert panels. We regularly analyze databases of OSHA citations to identify common areas of noncompliance in facilities.

Exponent engineers are well versed in NFPA Standards, and many serve as members of the technical committees or technical correlating committee responsible for the following standards related to combustible dust:

  • NFPA 61 — Standard for the Prevention of Fires and Dust Explosions in Agricultural and Food Processing Facilities
  • NFPA 68 — Standard on Explosion Protection by Deflagration Venting
  • NFPA 69 — Standard on Explosion Prevention Systems
  • NFPA 91 — Standard for Exhaust Systems for Air Conveying of Vapors, Gases, Mists, and Noncombustible Particulate Solids
  • NFPA 484 — Standard for Combustible Metals
  • NFPA 499 — Recommended Practice for the Classification of Combustible Dusts and of Hazardous (Classified) Locations for Electrical Installations in Chemical Process Areas
  • NFPA 652 — Standard on the Fundamentals of Combustible Dust
  • NFPA 654 — Standard for the Prevention of Fire and Dust Explosions from the Manufacturing, Processing, and Handling of Combustible Particulate Solids
  • NFPA 655 — Standard for Prevention of Sulfur Fires and Explosions
  • NFPA 664 — Prevention of Fires and Explosions in Wood Processing and Woodworking Facilities



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