How Often Should a Restaurant Hood Be Cleaned? A Guide to NFPA 96 Frequencies

Grease is the fuel in most restaurant exhaust fires. Every time food is cooked, grease-laden vapor rises into the hood, through the filters and into the ductwork and exhaust fan. Some of that grease condenses and sticks. Over time the buildup becomes a fire hazard that can carry flames from the cooking line through the roof.

That’s why commercial kitchen exhaust systems are cleaned on a schedule. The most widely used reference for that schedule is NFPA 96, Standard for Ventilation Control and Fire Protection of Commercial Cooking Operations.

Frequency depends on what — and how much — you cook

NFPA 96 does not set one interval for every kitchen. It links inspection frequency to the type and volume of cooking. In general terms, the standard’s schedule looks like this:

The exhaust system is inspected at these intervals, and if it is found contaminated with deposits from grease-laden vapors, it must be cleaned. In practice, most restaurants schedule cleanings at these intervals because buildup is almost always present.

The edition of NFPA 96 adopted in your jurisdiction, and your local fire authority, determine what applies. Actual buildup can justify more frequent cleaning than the minimum.

Which category is my kitchen?

Most full-service restaurants fall into the moderate- or high-volume range. A sports bar running fryers all day, a steakhouse with a charbroiler, a wok-heavy menu or a 24-hour diner is likely high-volume. A church kitchen used for monthly fellowship meals is likely low-volume.

If your menu or hours change — adding a charbroiler, extending hours or opening for breakfast — revisit your cleaning frequency.

What a proper hood cleaning includes

A complete cleaning covers the entire exhaust path, not just the parts you can see:

1. Hood interior and plenum — the space behind the filters, where grease collects heavily
2. Grease filters — cleaned or replaced
3. Ductwork — horizontal and vertical runs, through access panels
4. Exhaust fan — usually on the roof, including the fan bowl and blades
5. Documentation — a service label/certificate and, ideally, before-and-after photos

If ductwork lacks access panels in the right places, a technician can’t reach every section. A good provider will note this and recommend corrective work rather than skipping it silently.

Signs your hood is overdue

• Grease dripping from filters or the hood edge
• Visible grease around the rooftop exhaust fan or roof membrane
• Reduced exhaust performance — a smoky or unusually hot kitchen
• The last service label is past the date your frequency requires
• A fire inspector, landlord or insurer has asked for documentation

Hood cleaning and your suppression system

Your kitchen fire suppression system and your exhaust hood work together. Suppression system detection and nozzles sit in the hood and ductwork, and grease buildup on fusible links and nozzles can affect performance. Many restaurants schedule hood cleaning and their semi-annual kitchen suppression inspection together so both are handled on one calendar.

Scheduling around your business

Hood cleaning is messy work, so it is normally done after closing or between shifts. Expect the crew to cover cooking equipment, contain runoff and leave the kitchen ready for the next service.

Key takeaways

• NFPA 96 links cleaning frequency to cooking type and volume — from monthly to annually.
• Clean the full system: hood, plenum, filters, ductwork and exhaust fan.
• Keep documentation, including photos and the service label.
• Coordinate hood cleaning with your suppression system service.

Ready to set up a cleaning schedule? Learn about our commercial kitchen hood cleaning or request a quote.

Sources & references

• NFPA 96 — Ventilation Control and Fire Protection of Commercial Cooking Operations