Does Your Facility Need a Dust Hazard Analysis?
Take the Self-Assessment
Combustible dust hazards can develop where fine particulate is generated, handled, transferred, collected, or stored. Material enters a facility as a powder, or processing generates finer particles through milling, grinding, drying, or material transfer. A Dust Hazard Analysis (DHA) evaluates where combustible particulate solids pose fire, flash fire, or explosion hazards, how those scenarios develop, and whether existing safeguards address them.
Use this self-assessment to identify combustible dust conditions, information gaps, and process changes that affect DHA applicability and scope. Select the answer that best describes your operation. The technical significance of each answer depends on the material, process, equipment, and operating conditions.
1. Does Your Facility Handle, Process, or Generate Dusts, Powders, Fines, Fibers, or Other Particulate Solids?
☐ Yes
☐ No
☐ Not Sure
Grinding, milling, crushing, cutting, sanding, and drying can generate fine particulate even when the incoming material is relatively coarse. The same holds for mixing, screening, conveying, packaging, and material transfer.
Location matters. The material entering the facility isn’t always the dust present at the point of concern. Attrition, size reduction, drying, and separation produce a finer fraction at specific process locations.
2. Do You Know Whether Any of These Materials Are Combustible or Capable of Forming an Explosible Dust Cloud?
☐ Yes, one or more are combustible or explosible
☐ No, testing indicates they are not combustible or explosible
☐ The materials have not been tested
☐ Not Sure
Combustibility determinations rely on representative material information. Particle size, moisture content, composition, and processing history all affect dust behavior.
When combustibility is unknown, material characterization establishes the technical basis for further hazard evaluation. Required testing varies by material, particle size, process conditions, and hazard scenario. It can include combustibility screening, Kst, Pmax, Minimum Ignition Energy (MIE), Minimum Explosible Concentration (MEC), Minimum Ignition Temperature (MIT), or Layer Ignition Temperature (LIT).
One catch: if existing test data represents incoming material but the process generates a finer or drier fraction, that data may not apply to the material actually present at the point being evaluated.
3. Can Your Process Generate Finer Particles or Change the Condition of the Material?
☐ Yes
☐ No
☐ Not Sure
Grinding, milling, crushing, cutting, sanding, drying, mixing, screening, conveying, recycling, and repeated material transfer all qualify.
Finer particles ignite more easily and burn faster in many materials, since particle size reduction increases the available surface area. Drying adds another variable, since it can change ignition sensitivity and combustion behavior.
4. Can Dust Become Airborne or Escape from the Process?
☐ Yes
☐ No
☐ Not Sure
Look at more than normal operation. Startup, shutdown, cleaning, maintenance, equipment opening, blockage clearing, and process upset conditions all create release opportunities.
Common release points include transfer stations, bag dumping operations, conveyor discharge points, flexible connections, access doors, mixers, packaging equipment, filter housings, and dust collection connections.
5. Can Dust Accumulate Outside Process Equipment?
☐ Yes
☐ No
☐ Not Sure
Look beyond floors and accessible equipment surfaces. Dust settles on structural members, beams, rafters, cable trays, ductwork, light fixtures, equipment tops, elevated ledges, and concealed areas too.
Deposited combustible dust can be disturbed and dispersed by an initial fire or deflagration. If an explosible concentration forms and an ignition source is present, the event can extend well beyond the equipment where it started.
6. Is Combustible Particulate Handled, Processed, Collected, Conveyed, or Stored Inside Enclosed Equipment?
☐ Yes
☐ No
☐ Not Sure
Think dust collectors, mills, grinders, mixers, dryers, silos, bins, hoppers, conveyors, bucket elevators, and pneumatic conveying systems.
When an explosible dust cloud ignites inside an enclosure, combustion produces a rapid pressure rise. Ductwork, conveyors, chutes, and pneumatic transfer lines can provide propagation pathways to connected equipment. Don’t stop the evaluation at the enclosure where ignition originates.
7. Does Your Facility Use a Dust Collection System for These Materials or Processes?
☐ Yes
☐ No
☐ Not Sure
Review the complete system: pickup points, ductwork, filters, the collector, hopper, discharge equipment, return-air arrangements, and connections to process equipment.
A dust collector concentrates fine particulate inside an enclosed volume. Treat the collector, connected ductwork, discharge equipment, and any explosion protection or isolation as one system, not separate components.
8. Could Credible Ignition Sources Be Present Where Dust Is Generated, Handled, Collected, Released, or Accumulated?
☐ Yes
☐ No
☐ Not Sure
Potential ignition sources include electrical equipment, hot surfaces, overheated bearings, mechanical friction or sparks, electrostatic discharge, open flames, welding, cutting, and other hot work.
Ignition sources get evaluated against the material and operating conditions, not in isolation. MIE data supports evaluation of electrostatic ignition sensitivity. Dust cloud or layer ignition temperature data supports evaluation of heated surfaces. The real question is whether a credible source and combustible particulate can ever occupy the same place at the same time.
9. Has Your Facility Experienced a Dust-Related Fire, Flash Fire, Deflagration, Explosion, Smoldering Event, or Significant Near Miss?
☐ Yes
☐ No
☐ Not Sure
Count smaller events, not just major incidents. Recurring dust collector fires, smoldering material, overheated equipment, bearing failures, sparks entering a collection system, or unexplained ignition provide information about process conditions and ignition mechanisms.
No incidents doesn’t mean no hazard.
10. Has Your Facility Already Completed a Dust Hazard Analysis for These Materials and Processes?
☐ Yes, for all relevant materials and processes
☐ Yes, but only for some materials, areas, or equipment
☐ No
☐ Not Sure
If Yes, when was the DHA last completed or reviewed?
☐ Less than 1 year ago
☐ 1 to 3 years ago
☐ 3 to 5 years ago
☐ More than 5 years ago
☐ Not Sure
Have there been significant changes since the DHA was completed?
☐ Yes
☐ No
☐ Not Sure
Watch for changes to raw materials or formulations, particle size or moisture content, process equipment, production rates, operating conditions, dust collection systems, process connections, facility layout, explosion protection, and explosion isolation systems.
An existing DHA reflects the materials, equipment, operating conditions, and assumptions in place when it was performed. Changes to those conditions can introduce new scenarios or alter the technical basis of the existing DHA. Process modifications need to loop back to DHA review through Management of Change. Treat the DHA as a living document, not a report you file away.
11. Has an Outside Party Asked Your Facility for a DHA or Combustible Dust Hazard Evaluation?
☐ Yes, an AHJ or fire official
☐ Yes, an insurer
☐ Yes, corporate/EHS
☐ Yes, a customer or other party
☐ No
☐ Not Sure
An external request can start the DHA conversation. It doesn’t set the scope. That still comes down to the materials, processes, equipment, and conditions at the facility.
What Do Your Answers Indicate?
Don’t just count Yes and No answers. One specific condition, like combustible material inside enclosed equipment, can matter more than several unrelated answers combined.
If You Answered ‘Yes’
The combination of ‘Yes’ answers determines what’s next:
- Known combustible or explosible material, plus dust generation, dispersion, accumulation, or credible ignition sources: identify where fire, flash fire, and explosion scenarios can develop.
- Dust inside enclosed equipment: evaluate the equipment and its connections as one complete hazard scenario, not just the vessel where ignition might start.
- Dust escaping or accumulating outside equipment: extend the evaluation to the surrounding building, not only the process itself.
- An existing DHA: compare it against current operating conditions and identify anything that’s changed since it was completed.
If You Answered ‘Not Sure’
Usually it comes down to a specific gap: untested material, an unreviewed process, or an existing DHA that hasn’t been checked against current operations. That gap sets the next step: material testing, process review, equipment documentation, facility inspection, or a fresh look at the existing DHA.
If Most of Your Answers Are ‘No’
That doesn’t rule out a DHA by itself. Applicability still comes down to the material, process, equipment, facility conditions, applicable codes and standards, and any requirements from the Authority Having Jurisdiction.
Final Note
A ‘Yes’ or ‘Not Sure’ answer doesn’t automatically mean you need a Dust Hazard Analysis. It flags a condition or information gap that needs further evaluation before DHA applicability and scope can be established.
If you’re unsure whether a DHA applies to your facility or need help defining the scope, contact Sigma-HSE. Our team can review your materials, processes, equipment, and available dust test data and identify what needs to be evaluated next.
This self-assessment is provided for general technical information. It is not a Dust Hazard Analysis and does not determine compliance with NFPA standards, OSHA requirements, or applicable fire and building codes. Facility-specific requirements should be evaluated based on the materials, processes, equipment, applicable codes and standards, and requirements of the Authority Having Jurisdiction.
