How Often Does a Restaurant Hood Need Cleaning? NFPA 96 Intervals Explained

If you run a restaurant in Denver, one of the first questions about your kitchen exhaust is simple: how often does it need to be cleaned? The honest answer is that it depends on what and how much you cook. This guide walks through the intervals that are commonly cited from NFPA 96, the standard that covers ventilation control and fire protection for commercial cooking operations, and explains how to confirm the schedule that actually applies to you.

Why cleaning frequency matters

Cooking produces grease-laden vapor. As it travels up through the hood, filters, duct and fan, some of it condenses and builds up on interior surfaces. Heavy grease accumulation inside an exhaust system is a fire risk, which is why fire codes and insurers pay close attention to it. Cleaning removes that buildup before it becomes a problem and keeps the system working the way it was designed to.

Commonly cited NFPA 96 intervals

NFPA 96 links inspection and cleaning frequency to the type and volume of cooking. The intervals most often cited are:

• Monthly: systems serving solid-fuel cooking, such as wood- or charcoal-fired equipment.
• Quarterly: systems serving high-volume cooking, such as 24-hour operations, charbroiling and wok cooking.
• Semi-annually: systems serving moderate-volume cooking.
• Annually: systems serving low-volume cooking, such as day camps, seasonal operations or senior centers.

Treat these as general guidance, not a ruling on your kitchen. Editions of the standard differ, local fire codes adopt and amend it, and the final call about which category you fall into is made by your fire inspector and often by your insurer too.

Inspection comes before cleaning

The standard is generally described as requiring regular inspection of the exhaust system, with cleaning required when grease buildup is found. In practice, that means a calendar interval is a starting point. If a system builds up grease faster than expected, for example because the menu changed or a second fryer was added, it may need cleaning sooner than the calendar says.

How to figure out which category you are in

• List your cooking equipment: fryers, charbroilers, griddles, woks, ovens and any solid-fuel equipment.
• Note your hours and how many covers or orders a day the line produces.
• Look at past service records and the date on any cleaning sticker on your hood.
• Ask your fire inspector how they classify your operation, and check your insurance policy for any stated frequency.

Signs a system is due sooner

• Visible grease dripping or pooling at hood edges or filter trays.
• Strong cooking odors in the dining room or building that did not used to be there.
• Smoke that lingers rather than clearing up the duct.
• A greasy residue on the rooftop around the fan.
• A change in menu, hours or volume since the last cleaning.

Keep records

Dated service reports show your inspector and insurer that cleaning happens on schedule. Keep them somewhere your managers can find them, and note any areas of the system that could not be reached so they can be addressed next time.

Fire suppression is separate

Hood cleaning and fire suppression system inspection are different services. Wet-chemical suppression systems are typically inspected on their own schedule by licensed suppression companies. A cleaning company can coordinate timing with yours, but should not be presented as doing the suppression inspection unless it actually does.

A practical way to plan

Start with your cooking type, confirm the interval with your inspector and insurer, and set a recurring schedule instead of waiting for a problem. Many operators find recurring visits easier to budget and less disruptive than emergency cleanings before an inspection.

Denver Hood Cleaning Co provides commercial kitchen exhaust cleaning for Denver restaurants, including scheduled plans. Call (714) 333-0178 to talk through your kitchen.