A commercial kitchen carries two fire protection obligations that are easy to confuse. One is the wet chemical suppression system in the hood, governed by NFPA 17A and inspected on a semiannual cycle. The other is the hood and duct system itself, governed by NFPA 96, which has to be inspected for grease buildup on a schedule set by how much and what kind of cooking happens under it, and cleaned whenever the inspection finds it. Fire marshals check both, insurers ask for both, and a restaurant that has one done and not the other is out of compliance. This article covers the intervals, what each service involves, and who is allowed to do it.
Intervals below follow the 2021 editions of NFPA 96 and NFPA 17A. The Authority Having Jurisdiction (AHJ) enforces a specific edition, and some jurisdictions license hood cleaners and suppression technicians separately.
Hood suppression service and grease inspections run on different schedules
| Item | Interval | Standard | Who |
|---|---|---|---|
| Suppression system inspection and service | Semiannual | NFPA 17A | Trained and certified person |
| Fusible links and glass-bulb elements | Fusible metal-alloy and glass-bulb fixed-temperature elements replaced at least semiannually; other detection devices examined and replaced per their listing | NFPA 17A, NFPA 96 | Certified person |
| Owner's inspection of the suppression system | Monthly | NFPA 17A | Owner or agent |
| Grease inspection of hood, ducts, and fan: solid fuel cooking | Monthly; cleaned when contaminated | NFPA 96 | Trained, qualified, and certified company |
| Grease inspection: high-volume cooking (24-hour, charbroiling, wok) | Quarterly; cleaned when contaminated | NFPA 96 | Same |
| Grease inspection: moderate-volume cooking | Semiannually; cleaned when contaminated | NFPA 96 | Same |
| Grease inspection: low-volume cooking (churches, day camps, seasonal) | Annually; cleaned when contaminated | NFPA 96 | Same |
| Class K portable extinguisher | Monthly inspection, annual maintenance | NFPA 10 | Owner monthly; certified person annually |
The semiannual suppression service
Every six months a trained and certified person inspects and services the wet chemical system: the cylinder pressure or weight, the piping and nozzles with their blow-off caps in place and aimed at the right appliances, the detection line and its fusible links or heat detectors, the manual pull station, the automatic gas shutoff valve or electrical shunt trip, and the interconnection to the building fire alarm where one exists. Fusible metal-alloy links and glass-bulb fixed-temperature elements are replaced at least semiannually, with the date on each; other detection devices are examined at the service and replaced on the schedule their listing and the manufacturer set. The service ends with the system re-armed, the tag updated with the date and the technician, and the owner told about anything that has changed under the hood: a new fryer where a range used to be means the nozzle coverage no longer matches the appliances.
Between services the owner has a monthly inspection of their own: the system is in place with the seals intact, the pressure gauge reads in range, the nozzle caps are on, the manual pull is accessible, and nothing has been added or moved on the cook line.
Hood and duct cleaning
NFPA 96 requires the hood, filters, ducts, and exhaust fan to be inspected for grease accumulation on a schedule keyed to the cooking, and cleaned to bare metal when the inspection finds it. Solid fuel cooking is monthly. High-volume operations, including 24-hour kitchens and any charbroiling or wok cooking, are quarterly. Moderate-volume cooking is semiannual, and low-volume operations such as churches, day camps, and seasonal businesses are annual. The cleaning is done by a company that is trained, qualified, and certified to do it, and after each cleaning the company posts a sticker or certificate on the hood with the date, the company, and the areas cleaned, and gives the owner a written report listing anything it could not reach. Inaccessible duct sections, missing access panels, and a fan that could not be tilted are the common findings, and each is a deficiency the owner has to resolve.
Where the two meet
The suppression technician and the hood cleaner are often different companies on different schedules, and the gap between them is where fires start: a hood cleaned in January and a nozzle blocked by grease by June, or a suppression system serviced on schedule over a duct that has not been cleaned in two years. The AHJ reads both records together. Contractors that do both, or that coordinate with the cleaner, can put both services on one building record so the owner sees the whole kitchen at once. The suppression trade page covers the question sets for hood systems, and the extinguisher requirements article covers the Class K unit every kitchen cooking with combustible oils or fats needs within 30 feet of the cooking.
Common questions
Can the restaurant clean its own hood?
Filters can be cleaned by staff as often as needed. The hood, ducts, and fan cleaning NFPA 96 requires has to be done by a trained, qualified, and certified company, with the certificate to show for it.
The suppression system was serviced; does that cover the cleaning?
No. They are separate requirements under separate standards, and a suppression tag does not satisfy the grease inspection and cleaning requirement.
What if the cooking changes?
A new appliance, a moved appliance, or a change from moderate to high-volume cooking changes both the nozzle coverage and the cleaning frequency. Tell the suppression contractor before the next service, not after.
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