Combustible dust isn't a "maybe." If the process can create an explosive condition, the exhaust system needs an explosion-control strategy that matches IFC and is documented on the drawings.
Plain English: Plain-English Highlights
510.1.5 explosion control is required (IFC-driven) Explosion control must be provided per the International Fire Code for systems conveying:
1. Combustible dust, or
2. Combustible refuse/stock that produces combustible dust, when concentrations/conditions could create a fire or explosion hazard.
If you claim "no hazard," that determination must be backed by a Dust Hazard Analysis (DHA) per IFC 2203.2.
510.1.5.1 screens at safety relief vents
If a screen is installed at a safety relief vent, it must be attached to readily release under explosion pressure (i.e., it can't "hold" the vent closed).
510.1.5.2 relief vent hoods/cowls/covers
Relief vents must have an approved noncombustible cowl/hood, or a counterbalanced relief valve/cover, arranged to prevent escape of hazardous materials, gases, or liquids.
On Plans: Why it matters
Common redlines: "explosion vent by others," no DHA basis, vent screens detailed like bird screens (non-releasing), and relief vent terminations that can discharge hazardous material toward people/equipment.
Code Path: Where to show it
M-001: "EXPLOSION CONTROL PER IFC (DHA PER IFC 2203.2 WHERE APPLICABLE)" + responsibility note (RDP/owner/industrial hygienist as applicable).
Plans/Roof plan: relief vent location, discharge direction, and separation from occupied areas/intakes where relevant.
Details: vent device/cowl/relief valve, and the "screen releases under pressure" requirement.
Equipment schedule/submittals: explosion-control method type (per IFC), basis reference to DHA (if used).
Check: Do
Put a clear DHA/IFC trigger note on the drawings when combustible dust exists.
Call out that screens at relief vents must release under explosion pressure.
Coordinate relief vent discharge so it doesn't create a new hazard.
Review Risk: Don't
Don't cover explosion control with a generic note and no IFC/DHA basis.
Don't use fixed screens that can restrict or defeat explosion relief.
Don't aim relief vent discharge toward walkways, doors, or service areas.
Field Tip: Field tip
Run the "DHA → RELIEF PATH" check:
1. Is there combustible dust? If yes → IFC explosion control required unless a DHA says otherwise.
2. If there's a relief vent: where does it discharge, and will any screen release under pressure?
If either answer is unclear → expect plan review comments.
Comment "IMC510-P4" if you want a paste-ready M-001 note set + a one-page "combustible dust exhaust" QA checklist.
Masterbuild QA Lens
Exhaust systems need a source-to-discharge story. Identify what is being captured, how it is captured, how it is routed, where it terminates, and what interlocks or separations protect the building.
Drawing / Submittal Check
Verify source classification, hood or pickup point, duct material, route, cleanouts or access, fan selection, discharge location, make-up air, controls, and required coordination with fire protection or alarms.
Common Review Risk
The expensive miss is treating all exhaust the same. Grease, dryer, dust, hazardous, smoke control, battery, and specialty exhaust systems carry different proof requirements.
When To Escalate
Escalate when exhaust involves grease, hazardous materials, combustible dust, battery charging, smoke control, rated shafts, energy recovery, or any discharge that can re-enter the building.
Kitchen Exhaust Coordination
For kitchen exhaust, tie the hood schedule, appliance lineup, grease duct route, cleanouts, fan discharge, fire suppression interface, and make-up air strategy into one reviewable story.
Special Exhaust Coordination
For specialty exhaust, start with the contaminant and source. Then confirm capture method, duct material, routing, discharge, separation, controls, and whether another consultant or AHJ review is required.