Combustible Dust

The reissue of the OSHA Combustible Dust National Emphasis Program (NEP) due to the fatal accident at Imperial Sugar has provided combustible dust hazards additional exposure throughout all industries. SMS provides a wide range of services related to combustible dust hazard characterization, prevention, and mitigation. These services include dust hazards analysis, combustible dust testing, onsite assessments, OSHA and NFPA compliance assistance, audit preparation, training, ignition source evaluation and vent sizing calculations. Our process safety professionals have served clients in a variety of industries including metal processing, wood/paper products, agriculture, food products, textiles, plastics, pharmaceuticals and many others.

Combustible Dust Hazard Assessment or Dust Hazards Analysis (DHA)

How can SMS help with my combustible dust hazards?

SMS has been working in the combustible dust industry for over 25 years. SMS specializes in process and site assessments that are based on both compliance with regulations and realistic risk reduction methods. SMS philosophy is to provide real solutions that are based on sound engineering and safety principles to our clients. This includes working closely with the safety and management teams of each location or process. For combustible dust, this means developing sampling plans, dust testing, gathering process safety information, conducting Dust Hazards Analysis, and making recommendations that are realistic, supported by data, and targeted at improving safety.

Who needs a Dust HA?

When a dust fails either combustibility or flammability screening tests (go/no-go) you are required to complete a Dust Hazards Analysis per NFPA 652 or any of the commodity specific regulations (i.e. NFPA 484 for metal dusts or NFPA 654 for Combustible Particulate Solids).

What is a Combustible Dust?

Most solid organic materials and metals are combustible when in a dust form.  This includes sugar, flour, wood, aluminum, titanium, etc.

Per OSHA, a combustible dust is “a solid material composed of distinct particles or pieces, regardless of size, shape, or chemical composition, which presents a fire or deflagration hazard when suspended in air or some other oxidizing medium over a range of concentrations.” For more information click here.

How do you conduct a Dust Hazards Analysis?

  • It must be led by a “qualified person”
  • Must evaluate the process and areas where fire, flash fire, and explosion hazards exist
  • When these hazards exist, the analysis must include documentation of
    • Safe operating ranges
    • Safeguards to manage fire, deflagration, and explosion hazards
    • Recommendations for additional safeguards where warranted, including a plan for implementation
  • Evaluation of both dust and fire/explosion propagation
    • Intended and unintended transport of combustible dust
  • Documentation of oxidizing atmosphere and credible ignition sources
  • Documentation of all areas that have sufficient quantity of combustible dust and potential:
    • Oxidizing atmosphere
    • Credible Ignition source
    • Credible suspension mechanism

What Hazard Assessment tools or methods should be used?

The acceptable methods list in NFPA 652 Appendix B and OSHA 1910.119 (PSM) include:

  • “what-if” analysis
  • Checklist & what-if (combined) analysis
  • Failure Modes and Effects Analysis (FMEA)
  • Fault Tree Analysis
  • Hazards and Operability Study (HAZOP)

What other items need to be addressed at part of a Dust HA?

  • Incident investigations related to combustible dusts
  • Electrostatic discharge (ESD) ignition sources
  • Sampling plan and locations for collecting dust for testing
  • Employee training
  • Venting calculations
  • Process safety programs required by NFPA
    • Operating procedures
    • Inspection, testing, and maintenance
    • Training
    • Contractors and contractor training
    • Emergency Planning and response
    • Incident investigation
    • Management of change
    • Document retention
    • Audits
    • Employee participation