NFPA 96 inspection and cleaning frequencies
NFPA 96 — the national standard for ventilation control and fire protection of commercial cooking operations — groups kitchens by what and how much they cook, then sets how often the exhaust system has to be inspected. Cleaning is required whenever that inspection finds grease. These are minimums, not targets.
| Cooking volume category | Typical kitchens | Inspection / cleaning frequency |
|---|---|---|
| Solid fuel cooking | Wood-fired, charcoal or mesquite grills, brick ovens and smokers | Monthly |
| High-volume cooking | 24-hour kitchens, hospital and institutional kitchens, busy fry-heavy operations | Quarterly (every 3 months) |
| Moderate-volume cooking | Standard sit-down restaurants, diners, hotel and banquet kitchens | Semi-annually (every 6 months) |
| Low-volume cooking | Church kitchens, seasonal businesses, day camps, occasional-use kitchens | Annually (every 12 months) |
What actually drives frequency
The category is a starting point. What moves a kitchen up the schedule is grease volume, and three things drive it: what you cook, how long the equipment runs, and how much of your line is fryers and char-grills. A breakfast place running two fryers for six hours loads a duct very differently than a wood-fired pizza kitchen running twelve.
Solid fuel is its own case because it produces both grease and creosote-type deposits, which is why it sits at monthly regardless of how busy the room is. At the other end, a church or camp kitchen that cooks a handful of times a month can hold an annual interval — as long as an inspection confirms it.
Airflow is the practical tell. When the kitchen gets hotter, smoke hangs at the line, or the fan sounds like it is working harder, grease has narrowed the system and it is past due whatever the calendar says.
What an inspector checks
An inspector is looking for measurable grease buildup in the places it collects rather than for a shiny hood canopy: the filters, the seams and corners inside the hood, the full run of ductwork including horizontal sections, and the exhaust fan and its housing on the roof. Access panels are part of it — a system that cannot be opened cannot be verified as clean.
They also look for the service record and the sticker on the hood. If the date is stale for your cooking category, that alone can be written up.
What documentation should look like
After a cleaning you should hold a record showing the date of service, what was cleaned, anything that could not be reached or cleaned and why, and the company and technician who did the work. A service sticker goes on the hood with the same date.
Before-and-after photos of the hood interior, duct access points and the rooftop fan are what make that record hold up — for a fire official, for a health inspector, and for an insurer after a claim. ARC leaves documentation with every job for that reason.
What happens if you skip it
Grease keeps accumulating in the duct and fan, where a flare-up at the line has somewhere to travel. That is the fire risk. Before it gets there, the ordinary consequences are a failed inspection and an order to correct, a harder conversation with your insurer, a hotter and smokier kitchen for your crew, and equipment working against restricted airflow.
None of that is dramatic and all of it is avoidable on a schedule. Figure out which row of the table above your kitchen is in, and hold that interval.
Frequently asked questions
- How often should a commercial kitchen hood be cleaned?
- NFPA 96 sets the minimum by cooking volume: monthly for solid fuel cooking, quarterly for high-volume and 24-hour operations, semi-annually for moderate-volume standard restaurants, and annually for low-volume kitchens such as churches, seasonal businesses and day camps.
- Does Michigan follow NFPA 96?
- Yes. NFPA 96 is the national standard for commercial kitchen ventilation control and fire protection, and Michigan follows it. Local fire officials and health inspectors check exhaust systems against it, and most insurers ask for proof of regular cleaning.
- Is the inspection interval the same as the cleaning interval?
- No. NFPA 96 requires the system to be inspected at those intervals; cleaning is required whenever the inspection finds grease buildup. A kitchen that cooks harder than its category suggests can need cleaning sooner than the schedule.
- What counts as cleaning the whole system?
- Hood, stainless filters, the full length of ductwork, and the rooftop exhaust fan. Cleaning only the visible hood canopy leaves grease in the duct and fan, which is where a fire spreads, and an inspector will note it.
- What documentation should I get after a cleaning?
- A record showing the date, the areas cleaned, any areas that could not be reached, and the name of the company and technician, plus a service sticker on the hood. Photos before and after make the record far easier to defend to an inspector or insurer.
- What happens if I skip hood cleaning?
- Grease accumulates in the duct and fan, which is a fire hazard and a code violation. It can mean a failed inspection, an order to correct, trouble with an insurance claim after a fire, and reduced airflow that makes the kitchen hotter and smokier to work in.
Not sure which interval your kitchen falls under? Tell us what you cook and we'll tell you straight.
Source for the frequencies above: NFPA 96, Standard for Ventilation Control and Fire Protection of Commercial Cooking Operations, published by the National Fire Protection Association. Your local fire official has final say on how it is applied to your building.