NFPA Combustible Dust Standards

Fine dust from wood, metal, sugar, grain, plastic and many other materials can burn explosively. NFPA publishes standards that explain how to find the hazard and control it. OSHA often points to them in citations.

• Plant Managers
• Safety Staff
• Insurers

Which standard applies

Key requirements (plain language)

• Dust Hazard Analysis (DHA): the owner must identify where combustible dust exists and the fire and explosion risks, and review it at least every five years or when processes change. A qualified person should lead it.
• Test the dust. Know its properties, such as particle size and explosibility.
• Housekeeping: limit dust layers on surfaces. A common rule of thumb is to clean when a layer covers about 1/32 inch over a significant area, though the standard uses specific criteria. Use vacuums approved for dust, not compressed air or dry sweeping.
• Control ignition sources: hot work, static, hot surfaces, mechanical sparks and electrical equipment suitable for classified areas. See Hazardous Locations.
• Dust collection: design for the hazard, keep collectors outside when possible, and provide explosion protection such as venting, suppression, isolation and flame arrestors.
• Management of change and training. See Management of Change.

Practical steps

• Identify dusty areas and equipment such as collectors, mills, conveyors and bins
• Complete or review the DHA and keep records
• Clean elevated surfaces and hidden ledges as well as floors
• Inspect collectors, vents and isolation devices regularly
• Use hot work permits and spark detection systems
• Train workers on dust hazards and emergency response

Last updated: October 8, 2026