Dust Hazard Analysis (DHA)
A unified dust hazard analysis to NFPA 660 with ATEX dust zones, engineered against Kst, Pmax, MIE and MIT testing
Dust Hazard
Analysis (DHA)
NFPA published NFPA 660 in 2024 as the unified combustible dust standard that consolidates NFPA 652, 654, 61, 484, 655 and 664. This is the largest shift in combustible dust regulation in thirty years and it accelerates the mandatory dust hazard analysis regime first introduced under NFPA 652 and now intensified after Imperial Sugar in 2008 which took fourteen lives, Hayes Lemmerz in 2003, Didion Milling in 2017 and a continuing string of CSB investigated grain, metal, plastic and pharmaceutical incidents. A defensible analysis combines combustibility and explosibility testing for Kst, Pmax, minimum ignition energy, minimum ignition temperature, layer ignition temperature and limiting oxygen concentration under the ASTM and EN methods, source of release and ignition source mapping, engineering controls across the protection hierarchy of containment, prevention and mitigation, and explicit treatment of the hybrid scenarios that mix gas and dust, which recent industry data shows are increasingly common. For your international operations our team also maps the ATEX dust zones 20, 21 and 22 under IEC 60079 10 2 alongside the NFPA framework.
How the study is executed
A structured, facilitated process that runs from scope definition through close out and produces defensible, actionable outputs.
Scope Dust Hazard Analysis per NFPA 660 (2024, superseding NFPA 652), compile combustible dust inventory by location (mills, conveyors, dryers, dust collectors, silos), identify process specific dust types, particle size distributions, and production rates, define DHA boundaries and applicable standards.
Design test programme covering Kst (ASTM E1226), Pmax, MIE (ASTM E2019), MIT (ASTM E1491 / E2154), MEC (ASTM E1515), LOC, and LIT, classify dust per St 0 / St 1 / St 2 / St 3 by Kst (0 / 0, 200 / 200, 300 / >300 bar·m/s), assess hybrid (gas + dust) atmosphere interactions, MIE depression and lowered MEC.
Identify and rank ignition sources per EN 1127 1 / IEC 80079 36, hot surfaces, static electrostatic discharge, mechanical sparks, open flames, spontaneous combustion, electrical equipment, and lightning, specify ignition source elimination controls per source type and dust St class.
Apply NFPA 660 / IEC 80079 37 protection hierarchy, prevention (inerting with N₂ / CO₂, LOC control, oxygen reduction), containment (pressure shock resistant design), mitigation (venting, suppression, isolation), specify combinations appropriate to vessel Kst class and process constraints.
Size explosion vents per NFPA 68 / EN 14491 (Kst based, with K factor and efficacy correction), design suppression systems per NFPA 69 (agent selection, nozzle coverage, system trigger delay), specify chemical / mechanical isolation valves to prevent flame and pressure propagation between vessels.
Produce ATEX Dust Zone 20 / 21 / 22 classification drawings per IEC 60079 10 2 for EU facilities, select equipment EPL Da / Db / Dc per zone, issue DHA finding register with risk ranking, vent sizing calculations, suppression/isolation specifications, ignition source control schedule, housekeeping programme, and FM Global aligned design dossier.
What the study covers in full
Outcomes of Dust Hazard Analysis (DHA)
- We surface the silent hybrid gas and dust hazard pattern that CSB cases increasingly cite
- We drive your venting, isolation and suppression engineering with real explosibility data
- We address the secondary explosion propagation pathway seen at Imperial Sugar and Didion
- We close ignition source coincidence with proper non electrical control
- Your analysis holds up under the NFPA 660 unified standard
- It withstands the OSHA combustible dust national emphasis programme and CSB style retrospective scrutiny
- It aligns with IEC 60079 10 2 dust zones 20, 21 and 22 and ATEX protection levels Da, Db and Dc
- It satisfies FM Global Data Sheet 7 76 and 7 32 for an insurer grade design
- We drive credible housekeeping programmes that prevent layered dust secondary events
- We sharpen your hot work, management of change and permit to work controls in dust handling zones
- We strengthen inspection scope on dust collector vent panels, isolation valves and suppression bottles
- We enable realistic operator training scenarios for dust fire and explosion response
- You avoid the catastrophic multi fatality and facility loss profile of Imperial Sugar in 2008
- You reduce FM Global and underwriter premium loadings on combustible dust occupancies
- You target venting, suppression and isolation capital at the genuinely St 2 and St 3 dusts
- You cut business interruption exposure on your dust handling assets
Codes & standards we work to
Triggers that signal the need
Where Dust Hazard Analysis (DHA) applies
We assess your mills, dryers, conveyors, silos and dust collectors.
We cover fine chemical powders, milling, micronisation and blending.
We address active ingredient powders, sugars, flour, starches and sterile dust hazards.
We handle aluminium, magnesium, titanium and additive manufacturing dusts.
We assess battery materials, electrode coatings and hydrogen systems.
We cover sawdust, pellet plants, biomass boilers and agricultural feeds.
Tangible deliverables
- A dust hazard analysis to NFPA 660 with a finding register and risk ranking
- A combustibility and explosibility test data pack covering Kst, Pmax, minimum ignition energy, minimum ignition temperature and layer ignition temperature
- A vent sizing calculation to NFPA 68 and EN 14491
- A suppression design to NFPA 69
- A mechanical and chemical isolation specification
- An ignition source inventory to EN 1127 1 and IEC 80079 36
- A hybrid gas and dust atmosphere assessment
- ATEX dust zone 20, 21 and 22 classification drawings
- A housekeeping and inspection programme specification
- An FM Global aligned design dossier for your insurer dialogue
Ready to start your project?
Speak with our team to scope an engagement tailored to your facility, regulatory context, and lifecycle stage.