Case Study
Dust Hazard Analysis (DHA) & Dust Testing Project for a Storage Facility
Scope and Objectives
A large warehousing and logistics provider planned to introduce a new bulk product that could generate combustible dust during handling and storage. Because OSHA relies on NFPA combustible dust standards as key benchmarks, the client needed to understand the implications of NFPA 652/660, confirm whether existing facilities were suitable, and identify any needed modifications. The SDS also lacked key combustible dust properties, so the data needed to support an NFPA‑compliant Dust Hazard Analysis (DHA) was missing.
Material Hazard Characterization
The first step was to characterize the dust using ASTM methods referenced by NFPA, including explosion severity (Kst, Pmax), Minimum Ignition Energy (MIE), Minimum Explosible Concentration (MEC), and layer/cloud ignition temperatures (MIT/LIT). Testing was completed at Sigma‑HSE’s accredited laboratories, confirming whether the material was explosible, and provided the ignition sensitivity and explosion severity data needed for the Dust Hazard Analysis (DHA) and any protection design.
Dust Hazard Analysis (DHA) and Facility Evaluation
Using the material‑specific data, our engineers performed a DHA per NFPA 652/ NFPA 660 to identify where combustible dust clouds and layers could occur and when fire, flash‑fire, or deflagration hazards would exist.
The Dust Hazard Analysis (DHA) included:
Identifying areas where combustible dust atmospheres could form and where fugitive layers could accumulate (e.g., transfer points, conveyor areas, loading/unloading).
Evaluating potential ignition sources (electrical equipment, mechanical sparks, hot surfaces, and electrostatic discharge) in light of the material’s MIE and ignition temperatures.
Reviewing existing dust control measures and explosion protections, and identifying shortfalls relative to NFPA guidance for containment, collection, and explosion protection.
Where indicated by the DHA, a hazardous (classified) area evaluation was performed to determine whether any areas warranted Class II (or Zone) classification based on credible dust clouds or hazardous layers.
Results
The client obtained the critical dust flammability and explosibility data missing from the SDS, enabling evidence‑based DHA decisions instead of assumptions.
The DHA identified a need for targeted local exhaust / dust collection in specific handling areas, directing investment into NFPA‑aligned LEV rather than generic ventilation.
Analysis against NFPA criteria showed that the existing enclosed luminaires (e.g., IP65‑type fixtures) did not require blanket replacement with Class II equipment in the evaluated areas, avoiding unnecessary capital costs.
Practical limits and guidance for storage quantities, stacking, and residence times were provided to manage self‑heating and dust accumulation risks, allowing safe, NFPA‑aligned handling of the new product. parameters.
