Guide
How often to inspect a commercial kitchen exhaust system
Your cook line makes grease. The question is how often someone qualified looks at the whole exhaust path — and when that look turns into a clean. Operators who only “clean when it looks dirty under the canopy” get surprised on duct and fan inspections.
Inspection interval by cooking type
Secondary industry sources cite NFPA 96 Table 12.4 (2024 ed.) as an inspection schedule. Confirm against the edition your city adopts.
| Cooking type | Typical examples | Inspect |
|---|---|---|
| Solid-fuel | BBQ, wood-fire pizza, charcoal | Monthly |
| High-volume | 24-hour kitchens, charbroil, wok lines | Quarterly |
| Moderate-volume | Most sit-down restaurants | Semiannually |
| Low-volume | Churches, day camps, seasonal, senior centers | Annually |
What good looks like
- Calendar matches your heaviest cooking type on site
- Inspection covers hood → filters → plenum → ducts → fan
- Written finding if cleaning is due; photos if cleaned
- Next-due date on the hood service label
What a cheap wipe looks like
- “We clean every 6 months” with no cooking-type logic
- Only filters or canopy wiped; ducts/fan never opened
- No measurement notes; no inaccessible-area callouts
- Sticker date with nothing behind it
Field detail to check tonight
- Hood sticker / service label — last service date and company name visible?
- Access panels — enough panels to reach horizontal and vertical duct, or “couldn’t access” forever?
- Rooftop fan — hinged for cleaning? Grease cup / containment present?
- Before/after photos — plenum, duct opening, fan interior — not just a shiny canopy
- Next-due date — on the report and on your wall calendar
Inspection vs cleaning (what the schedule actually is)
Secondary sources summarizing NFPA 96 (2024 ed.) treat Table 12.4 as an inspection cadence, not a fixed “clean every X months” calendar. Cleaning is triggered when grease depth crosses the limits your AHJ applies. Confirm section numbers and limits against the edition your city adopts — do not treat this page as the code book.
| Where grease is measured | Depth often cited as the clean trigger (secondary) |
|---|---|
| Hoods, filters / grease removal devices, fans, ducts | ~0.002 in (≈50 µm — about copy-paper thickness) |
| Other surfaces inside the system | ~0.078 in (≈2 mm) |
| Fan housings | ~0.125 in (⅛ in) |
Practical operator read: solid-fuel and high-volume lines usually need a real clean on the same visit as the inspection. Moderate- and low-volume kitchens may pass an inspection without a full clean that cycle — but they still need the written report and a current service label. Related maintenance cadences secondary sources also flag: wet-chemical suppression service on its own schedule (often semiannual), and grease drip containers checked/emptied on a short staff cadence (often weekly).
Volume-specific planners on this site
Use the table above to pick your tier, then open the matching planner:
- Solid-fuel (wood/charcoal) — monthly reality check
- High-volume fryer line — quarterly planner
- Moderate-volume restaurant — semiannual checklist
- Low-volume / church kitchen — annual minimums
Who it’s for / not for
- For: kitchen managers, multi-unit facilities, owners planning vendor cadence
- Not for: treating this table as a legal determination — your AHJ and adopted code edition control
Sources
- Facilitec Southwest — NFPA 96 frequency / inspection-vs-cleaning guide (secondary; depth table + Table 12.4 summary)
- Facilitec — NFPA 96 codes reference (secondary)
- Total Fire Protection — frequency summary (secondary)
- IKECA FAQs
Next step
Open your last invoice or sticker. If the date doesn’t match the cooking-type row above, schedule an inspection — not a canopy wipe — and require duct and fan photos.