Get the combustible dust spec right — before it’s your change order
Your stamp goes on the drawings. Loop us in at schematic and your design accounts for the DHA, explosion venting, and collector space before any of it becomes an RFI, a redesign, or a change order you have to explain.
Allied Member, American Institute of Architects
Why design teams keep getting surprised by combustible dust
NFPA 660 is the unified combustible dust standard, in force since January 1, 2026 — it consolidates the former 652, 654, and 664 into one code. The change that lands on your desk: the owner has to complete a dust hazard analysis (DHA) for any facility handling combustible dust, and your building has to be designed to accommodate whatever that DHA requires.
That means vent locations, collector space, structural reinforcement for vent panels, housekeeping access paths, and utility routing for pulse-cleaning. Get it wrong at schematic and you’re looking at change orders, permit delays, redesign fees — or liability questions after occupancy.
You’ve seen how it goes. The mechanical engineer sizes the collector on old assumptions. The architect places it where it won’t fit once explosion vents are added. The structural engineer never gets the loading data. Everyone points fingers at submittal time. One conversation at schematic prevents all of it.
The earlier we’re in, the more we can do for you
Schematic design
Your design still has maximum flexibility. We can shape mechanical room size, roof and wall space for explosion vents, structural loading, housekeeping access, and utility routing before anything is locked.
Design development
Still workable, but your options narrow. Equipment locations are usually set. We can provide Revit families, spec sections, and guidance — but major moves get expensive from here.
Construction documents
Now we’re answering RFIs and turning submittals. Significant scope changes trigger change orders. Your client won’t be happy — and neither will you.
Do you have to provide or stamp the DHA? No.
NFPA 660 is clear: the owner — or a qualified third party — is responsible for completing the dust hazard analysis. You’re not required to write or stamp it.
But your downstream responsibility is real. Your building has to accommodate whatever the DHA requires — roof and wall space for venting, structural capacity for vent panels, room for collectors and duct risers, housekeeping access, routing for suppression or isolation valves. If the DHA calls for 12 m² of roof venting and there’s no roof space in your set, you’re in change-order territory.
That’s where we come in early. We coordinate the DHA and testing process — dust type, process volumes, housekeeping practices — and prepare review-ready documentation for your team. You keep the drawing and the seal; your licensed PE stamps the final work where the AHJ requires it. We’re not a licensed engineering firm and don’t stamp drawings or reports.
What your design team receives
Engineering documentation
Lab-tested Kst/Pmax data, NFPA 68 vent sizing calculations, placement recommendations, and structural loading notes — prepared so your licensed PE can review and stamp.
BIM / Revit families
Parametric families for cartridge collectors, baghouses, ductwork, and explosion vents — accurate dimensions, clearance zones, shared parameters. LOD 300–400, Revit 2020+.
Specification packages
Complete three-part CSI specs (Section 23 40 00), customized for your dust type — wood, metal, food, pharma — with performance requirements, submittals, QA, and warranty terms. Drops into your project manual.
Submittal & RFI support
Submittals returned within 48 hours, RFI responses same day when possible. During construction you get a direct line — not a support ticket. Your schedule is our schedule.
Whether you’re drawing the building or writing the spec
Architects, MEP engineers, and PEs need different things from us at different phases. Here’s how we work with each.
Your layout has to accommodate the DHA before it’s locked.
We work with your project architect from schematic so the building can support whatever NFPA 660 requires — mechanical room sizing, roof and wall space for explosion vents, structural loading for vent panels, and housekeeping clearances.
- Schematic-stage DHA scope consultation — no charge
- Space and clearance requirements for your drawings
- Explosion vent sizing and placement guidance
- AHJ expectations across AZ, CA, NV, NM, and UT
- Revit families ready for coordination
You write the spec. We make sure it works — and we’re there when the RFIs hit.
Your mechanical spec drives the contractor’s selection. If Section 23 40 00 isn’t tight, you get submittals that don’t match the DHA — or equipment that can’t be installed where it was drawn. We give you a direct contact during construction, not a general inbox.
- Section 23 40 00 spec sections for your dust type
- CFM sizing guidance by process and dust classification
- NFPA 68 vent sizing calculations (Pred = 0.1 bar)
- Revit families — LOD 300–400, Revit 2020+
- 48-hour submittal turnaround, same-day RFI response
Common Kst & Pmax values
Indicative ranges for early planning. Actual values for your facility require lab testing of the specific dust.
| Material | Kst (bar·m/s) | Pmax (bar) | St-Class | Typical protection |
|---|---|---|---|---|
| Wood dust (pine, oak, MDF) | 100–224 | 8.0–9.5 | St 1–2 | Venting or suppression; isolation often required |
| Aluminum | 400–600 | 11.0–12.5 | St 3 | Suppression or isolation mandatory; venting limited |
| Sugar | 100–300 | 8.5–9.5 | St 1–2 | Venting common; suppression for enclosed systems |
| Flour (wheat) | 60–300 | 8.0–9.5 | St 1–2 | Venting or suppression; housekeeping critical |
| Cornstarch | 100–200 | 8.0–9.0 | St 1–2 | Venting common; suppression for enclosed systems |
| Phenolic resin | 200–400 | 9.0–10.5 | St 2–3 | Suppression or flameless venting |
Need the expanded tables, NFPA 68 vent sizing, and a DHA scoping questionnaire? They’re in the Spec Starter Kit below. For the full breakdown, see the Kst values guide.
Designing to the standard
NFPA 660 has been the unified combustible dust standard since January 1, 2026, bringing the former NFPA 652, 654, and 664 under one code. For your set, the practical requirements are space, structure, and access — designed in early, not retrofitted at CD.
Your facility might involve woodworking, metal fabrication, food manufacturing, pharmaceutical, aerospace, or battery production — each with its own dust behavior and protection strategy.
Your team navigates building codes, fire marshals, and AHJ expectations that vary across Arizona, California, Nevada, New Mexico, and Utah. We flag the issues before they hit permitting.
What NFPA 660 requires
Dust hazard analysis (DHA): identify combustible dust sources; evaluate Kst/Pmax and ignition risk.
Engineered controls: venting, suppression, or isolation sized to the dust.
Space & structure: room for collectors, duct risers, and vent panels — with the structural capacity to carry them.
Access: housekeeping paths and maintenance clearances designed in.
Documentation: a DHA report, design records, and submittals the AHJ will accept.
Get your free spec starter kit
Expanded Kst tables, a DHA scoping questionnaire, a Section 23 40 00 spec template, NFPA 68 vent sizing reference, and an AHJ checklist — sent to your inbox.
When your project may not need us
Not every project needs early specialist coordination. If your facility handles only non-combustible dust — nuisance particulate, HVAC filtration, light housekeeping dust — standard mechanical specs and a competent MEP engineer are likely enough without bringing us in at schematic.
If your project is a small tenant improvement in an existing facility where dust collection is already designed and installed, there’s probably nothing for us to add at the design stage — a maintenance assessment is the right first call there.
And if you’re not sure whether your project involves combustible dust, that question itself is worth a 15-minute call. We’ll tell you honestly whether you need us or not.
We come to your office. We bring lunch. We talk NFPA 660.
Your team gets a clear, one-hour picture of what combustible dust compliance asks of architects and engineers — real project examples, a spec walkthrough, and the Spec Starter Kit to keep. No sales pitch in the session.
In-person or virtual
We come to your office across AZ, CA, NV, NM, and UT — or join by video if that’s easier.
One hour, no fluff
Timing, space planning, DHA scope, and spec writing — what design teams actually need. Not a product brochure.
Take-home spec kit
Everyone keeps the printed kit — Kst tables, DHA checklist, Section 23 40 00 template, and NFPA 68 vent sizing reference.
Working on a project with combustible dust?
Loop us in at schematic and your design accounts for the DHA, explosion protection, vent sizing, and collector space — before any of it becomes a change order. We’ll guarantee it passes inspection.
Serving AZ, CA, NV, NM & UT · Allied Member, American Institute of Architects