Start from the dust hazard analysis and the list of process equipment that handles particulate, then trace each collector, duct, isolation device, vent, and hazard area through every discipline. AI can flag conflicts; the engineer of record and the authority having jurisdiction decide compliance.
What does NFPA 660 cover?
NFPA 660 is the Standard for Combustible Dusts and Particulate Solids. NFPA’s page states that NFPA 660 combines NFPA 61, NFPA 484, NFPA 652, NFPA 654, NFPA 655, and NFPA 664 under its Combustible Dust Document Consolidation Plan, so agricultural and food dusts, combustible metals, the fundamentals of combustible dust, particulate solids, sulfur, and wood processing now sit in one standard. The pages for the older standards show their last stand-alone editions.
NFPA’s official NFPA 660 page identifies the 2025 edition as current when checked on October 5, 2026. Confirm the edition, local amendments, and project scope that actually govern the work. The publisher’s newest edition does not establish local adoption.
Projects designed under one of the older standards may still cite it, and the authority may adopt either the consolidated standard or a predecessor. Record which document the specifications, the dust hazard analysis, and the authority name before comparing anything. Deflagration venting and explosion prevention have their own references in the NFPA 68 venting guide and the NFPA 69 prevention guide, and the exhaust ductwork that carries dust follows the NFPA 91 process exhaust guide.
Start from the dust hazard analysis and the equipment list
Collect the dust hazard analysis or its summary, the process flow diagram and equipment list, the process and equipment layout, the dust collection ductwork plans and sections, the collector, isolation, and venting product data, the architectural plans and sections for rooms where dust can accumulate, the electrical hazardous area classification drawings, the fire protection drawings, and the specifications for the dust collection system.
Mark which equipment handles which material. A plant can have a wood dust system, a metal dust system, and a food ingredient system side by side, and each may follow a different part of the standard.
Follow the dust from source to collector
| Review question | Sources to compare | Decision to record |
|---|---|---|
| Material and equipment | Dust hazard analysis, equipment list, process layout | Confirm each piece of equipment that handles dust appears in the analysis and on the layout with the same tag. |
| Collectors | Equipment schedules, product data, site and roof plans | Match each collector’s tag, location, and indoor or outdoor placement across sources. |
| Duct routing | Ductwork plans, sections, architectural plans | Trace each duct from pickup to collector and match the route through walls, floors, and roofs. |
| Isolation and venting | Process and ductwork plans, product data, roof and elevations | Check that isolation devices and vents named in the analysis are drawn, and that vent discharge paths are shown. |
| Hazard areas | Electrical classification drawings, process layout, analysis | Compare the drawn classified areas with the equipment and rooms the analysis identifies. |
| Building and housekeeping features | Architectural plans, sections, specifications | Identify ledges, ceilings, and concealed spaces the analysis or specifications address but the drawings leave unclear. |
Carry hazardous areas into the NFPA 70 electrical guide, protection inside collectors into the NFPA 15 water spray guide where specified, and the plant itself into the manufacturing project review.
Example: a collector that moved indoors
Hypothetical example. The dust hazard analysis and the original site plan place a dust collector outside, with a vent discharging away from the building. A later process layout moves the collector inside a production room, while the roof plan and ductwork still show the outdoor arrangement and no vent duct to the exterior.
The process layout shows the dust collector inside the production room, but the dust hazard analysis, site plan, and ductwork plans place it outside with a vent to open air. Please confirm the collector location and update the venting, isolation, and analysis to match.
The engineer of record confirms the arrangement and revises the documents. Whether the new location and protection meet the adopted standard is the engineer’s and authority’s decision.
Review a combustible dust package with Groundbook
Upload the current project PDFs and relevant specifications to Groundbook. Identify the governing issues and add the applicable NFPA 660 reference from a copy you are licensed to use, where the license permits uploading it. State the edition, amendments, review area, and known exclusions in your instructions.
Compare the dust hazard analysis, equipment list, process layout, dust collection ductwork plans, collector, isolation, and venting data, architectural plans, electrical classification drawings, and specifications. Flag equipment, collector locations, routes, protection devices, and hazard areas that differ between sources. Use the supplied NFPA 660 edition where applicable and cite both sources.
Groundbook links each potential finding to the sheets behind it. It does not decide whether a material is combustible or perform a dust hazard analysis.
Document review does not test dust, size vents, collectors, or ducts, or approve the installation. Those decisions remain with the engineer of record, the owner’s dust hazard analysis, and the authority having jurisdiction.