The technical guidance on this page reflects these published codes and standards, which your local authority (AHJ) adopts, amends, and enforces. It is educational, not engineering or legal advice — confirm the current requirements for your jurisdiction.
Grease-laden vapor from cooking condenses on hood surfaces, filters, ductwork, and the exhaust fan. That buildup is fuel, and it sits directly above open flame — which is why commercial exhaust cleaning is governed by NFPA 96, the Standard for Ventilation Control and Fire Protection of Commercial Cooking Operations. This is not a nice-to-have. Inadequate cleaning is a leading cause of restaurant fires, and an uncleaned system is the first thing an insurer will point to after one.
NFPA 96 doesn't set one universal interval; it ties frequency to how much and what you cook. The widely used minimum benchmarks are:
| Cooking operation | Minimum inspection/cleaning frequency |
|---|---|
| Solid fuel (wood, charcoal) | Monthly |
| High volume (24-hour, charbroiling, or ~12–16 hrs/day) | Quarterly (every 3 months) |
| Moderate volume (most sit-down restaurants, ~6–12 hrs/day) | Semi-annually (every 6 months) |
| Low volume (churches, seasonal, day camps) | Annually |
These are floors, not ceilings. The authority having jurisdiction (AHJ) — your fire marshal or inspector — can require more frequent cleaning based on what they find. Heavy wok, char, or fryer use loads a system faster than the calendar suggests.
NFPA 96 requires the exhaust system to be cleaned by properly trained, qualified, and certified persons — and the whole system, meaning hood, filters, ducts, and fan, not just the visible grease. NFPA itself doesn't certify contractors; technicians earn credentials through independent bodies such as IKECA. Wiping the hood front yourself between services is fine, but the full-system cleaning that satisfies code and insurance needs a certified contractor who documents the work.
After each cleaning, a compliant contractor leaves a service report and a dated certification sticker on the hood noting areas cleaned and anything inaccessible. Keep those records — they're what a fire inspector checks and what your insurer will demand if you ever file a claim. Skipping cleaning can void fire-insurance coverage, so a rejected claim can be far costlier than the cleaning. Also confirm your cleaning company carries general liability and workers' comp; without it, an accident on your property becomes your exposure.
A code-compliant cleaning is far more than wiping the stainless. NFPA 96 expects the entire grease path to be brought back to bare metal where accessible, which is why the job usually happens after hours with the line cold:
Ask the contractor whether any areas were inaccessible; those spots keep collecting grease and are exactly where inspectors and insurers look after a fire. Adding access panels is a small cost that keeps the whole system cleanable.
Tip: Set the cleaning interval to your real cooking load, not the minimum on paper. If your fryers and char run all day, quarterly may not be enough — and your inspector can say so. See requirements by location for local AHJ rules.