Combustible Dust Hazard Analysis (DHA) — NFPA 660 / NFPA 652 Methodology
The hazard analysis required by NFPA 652, now carried into NFPA 660, for any facility handling combustible particulate solids. Hazard identification, mitigation, dust collector evaluation, and the housekeeping and management procedures fire marshals and OSHA NEP inspectors expect. NFPA 652 section 7.2.2 requires the DHA to be performed or led by a qualified person: this is the structure, the worksheets and the record, not that person.
When this template is required
Required by NFPA 652 — now the fundamentals chapters of NFPA 660, Standard for Combustible Dusts and Particulate Solids, 2025 edition, effective December 6, 2024 — for facilities handling combustible particulate solids. NFPA 652 required a DHA for all new processes on issue and, for existing processes and facility compartments, by September 7, 2020 under section 7.1.1.2: five years after the effective date of the first edition, extended from the three years the 2016 edition allowed. The DHA must then be reviewed and updated at least every five years. OSHA enforces dust hazards under the General Duty Clause and the Combustible Dust National Emphasis Program.
Why this template
Qualified person and team record
A DHA is only as defensible as the record of who performed it. Appendix C captures the qualified person and each team member with the knowledge, training and experience the qualification rests on; Appendix O is the pre-analysis readiness checklist that assembles material data, test results, drawings and process descriptions before the first walkdown.
NFPA 660 / NFPA 652 methodology
NFPA 660, Standard for Combustible Dusts and Particulate Solids (2025 edition, effective 6 December 2024), consolidated NFPA 61, 484, 652, 654, 655 and 664 into one standard; its fundamentals chapters carry NFPA 652 forward. Fire code adoption lags, so most jurisdictions still enforce NFPA 652-2019 plus a commodity standard. The template works to the NFPA 652 methodology, names NFPA 660 as the current document, and crosswalks the industry-specific standards.
Combustibility data worksheet
Critical to a defensible DHA: the explosibility characteristics of your dust — Kst (deflagration index), Pmax (maximum explosion pressure), MIE (minimum ignition energy), MIT (minimum ignition temperature). The worksheet captures lab test results and references for each material.
Dust collector evaluation
Dust collectors are typical incident locations. The evaluation worksheet covers location (indoor vs outdoor), deflagration protection (venting, suppression, isolation), hopper design, and fire/explosion prevention measures.
What you receive
- DHA template (Word .docx) — NFPA 652 / NFPA 660 methodology
- Combustibility / explosibility data worksheet (Kst, Pmax, MIE, MIT)
- Process hazard identification matrix (per process step)
- Dust collector evaluation worksheet (deflagration protection, location, hopper)
- Housekeeping plan with frequency matrix
- Ignition source assessment (electrical, mechanical, hot work, static)
- Mitigation measures selection guide (explosion venting, suppression, isolation)
- Management of Change procedure for new equipment / materials
- 5-year DHA review schedule
- Industry-specific reference: NFPA 654 / 484 / 61 / 664 crosswalk
How you get it
This document is written and reviewed against the standard it cites, and it is ready now. The download link is emailed as soon as your payment clears.
Revisions included — if something about your operation changes what the document should say, reply to the delivery email and we will amend it.
Who buys this
- Food and grain processing facilities (NFPA 61)
- Wood and pulp/paper manufacturing (NFPA 664)
- Metal manufacturing (NFPA 484) — aluminum, magnesium, titanium
- Chemical, dye, and pharmaceutical (NFPA 654)
- Plastics and rubber manufacturing
- Bulk material handling facilities
- 3D printing / additive manufacturing (metal powders)
Frequently asked
Who needs a DHA?
Per NFPA 652 §7 — now the fundamentals chapters of NFPA 660 — any facility that handles, processes, or generates combustible particulate solids must perform a DHA. This includes: food and grain processors, wood and paper manufacturers, metal manufacturers (aluminum, magnesium, titanium), chemical / pharmaceutical processors, plastics and rubber manufacturers, and many others. If your facility has dust that can ignite or explode, you likely need a DHA — even if the dust is a byproduct rather than a primary product. Note who must lead it: NFPA 652 section 7.2.2 requires the DHA to be performed or led by a qualified person — someone who can demonstrate knowledge, training and experience in combustible dust hazards and in the analysis methodology. This template is the structure, the worksheets and the record; it does not supply that person, and vent, suppression and isolation sizing must be designed under NFPA 68 / NFPA 69 by someone competent in explosion protection design. Existing processes and facility compartments were required to have a DHA by September 7, 2020, so a facility without one is overdue rather than early.
What's NFPA 652 vs the industry-specific standards?
NFPA 652 is the umbrella standard — applies to all combustible particulate solids. Industry-specific NFPA standards layer on top with more detailed requirements: NFPA 654 (chemical, dye, pharmaceutical, plastic), NFPA 484 (combustible metals), NFPA 61 (agricultural and food), NFPA 655 (sulfur), NFPA 664 (wood). NFPA 660 (2025 edition, effective 6 December 2024) has since consolidated all six of those documents into a single standard, with fundamentals chapters carried forward from NFPA 652 and a commodity chapter for each of the others; NFPA 652-2019 is the last standalone edition. Because fire codes adopt by reference and adoption lags publication, most jurisdictions still enforce NFPA 652 plus a commodity standard — confirm which document and edition your authority having jurisdiction has adopted. The DHA template covers the NFPA 652 methodology, names NFPA 660 as the current standard, and crosswalks the industry-specific standards.
What is Kst?
Kst is the deflagration index — a measure of how rapidly a dust explosion develops pressure. Measured in bar·m/s. Dusts are classified: St 0 (non-explosive, Kst = 0), St 1 (weak, Kst ≤ 200), St 2 (strong, Kst 200-300), St 3 (very strong, Kst > 300). Most building materials and food dusts are St 1; metals and some chemicals can be St 2 or St 3. The Kst value drives explosion protection design (vent sizing, suppression capacity, etc.).
How often does the DHA need to be reviewed?
NFPA 652 §7, now the corresponding fundamentals chapter of NFPA 660, requires review at least every 5 years, and whenever significant changes occur — new materials, new equipment, new process configurations. The template includes the 5-year review schedule and the Management of Change procedure for triggering off-cycle reviews.
Does OSHA enforce NFPA 652?
OSHA does not directly adopt NFPA 652 or NFPA 660 as a standard. Combustible dust enforcement comes from the General Duty Clause (Section 5(a)(1)) when serious hazards exist, plus the Combustible Dust National Emphasis Program (CPL 03-00-008) which directs targeted inspections of dust-handling facilities. Most state and local fire codes adopt the NFPA combustible dust standards by reference through the IFC, and the adopted edition is often several cycles behind — in most jurisdictions still NFPA 652-2019 with a commodity standard rather than NFPA 660. In practice, OSHA inspectors and fire marshals both expect to see a DHA meeting the NFPA methodology at facilities with combustible dust.