Short answer: Commercial cooking that produces grease-laden vapors needs a listed automatic fire-extinguishing system under the hood, tested to UL 300 if it's a pre-engineered wet- or dry-chemical system. A new kitchen needs one designed around its exact appliance line-up, and an existing system has to be brought into compliance when appliances are replaced or moved or the cooking oil changes. Your local fire department or fire protection district reviews the plans and witnesses the acceptance test.
STL Kitchen Suppression doesn't design or install systems. We're an independent referral resource: with your consent, we'll pass your request to an independent fire protection provider that serves your area, and that provider designs, permits, and installs the work.
When You Need a New or Modified System
The fire codes used around St. Louis point to the same set of triggers. Under the IFC (2018 IFC §904.12 in the City of St. Louis; 2021 IFC §904.13 in many county and St. Charles County jurisdictions), an existing system must be brought into compliance when the cooking media changes, appliances are moved, or appliances are replaced. The 2021 edition of NFPA 96 adds a fourth trigger for systems not listed to UL 300: the equipment is no longer supported by the manufacturer.
- New restaurant or commissary kitchen. Every grease-producing appliance under the hood needs protection.
- Remodel or new hood. New hoods, ducts, or a rearranged line change what the system must cover.
- Appliance swap. Replacing a griddle with a fryer changes the nozzle type, position, and flow points the system needs.
- Moving equipment. Appliances must stay in their design position under the nozzles.
- Adding a smoker box or solid fuel. NFPA 96 says a solid-fuel holder shouldn't be added to an existing appliance until the service provider has evaluated the system.
- Old dry-chemical system. See the UL 300 section below.
ANSUL's own owner's guide says the same thing in plain terms: before you change your kitchen layout, have a trained provider evaluate the system.
UL 300 Upgrades
UL 300 is the fire-test standard for kitchen suppression systems, effective November 21, 1994. It was tightened because low-fat vegetable oils and well-insulated fryers made most older dry-chemical agents ineffective. Signs of a pre-UL 300 system include dry-chemical agent, nozzles about 2 inches across (wet-agent nozzles are about ¾ to 1 inch), and no UL 300 label on the tank or cabinet.
Pre-UL 300 systems aren't automatically illegal. UL leaves the original listings in place, and your fire official decides. But they're generally considered obsolete, they must be brought up to UL 300 when the cooking oil, appliances, or layout change, and a lack of replacement parts can void the listing. Some insurers also require UL 300. The Fire Equipment Manufacturers' Association recommends upgrading when hoods, ducts, or appliances change, or when the manufacturer, the AHJ, or the insurer recommends it. Our UL 300 compliance guide explains how to tell what you have.
Design Considerations
A pre-engineered system has to be installed within its manufacturer's listing and, for wet-chemical systems, NFPA 17A. These are the points worth discussing with the provider:
- Nozzle coverage. Each appliance gets nozzles matched to its type and size, plus nozzles for the plenum and duct. Some systems, like ANSUL R-102, offer overlapping coverage across a run of appliances, and Amerex's Zone Defense design lets appliances move within its listing without moving nozzles. That flexibility matters if you rearrange the line often.
- Detection. Most systems use fusible links in the hood and duct. Some hood-integrated systems, like CaptiveAire's CORE, use electronic detection.
- Manual pull station. The IFC places it at or near a means of egress, 10 to 20 feet from the exhaust system, mounted 42 to 48 inches above the floor and labeled for the hazard it protects. The 2021 IFC adds that it must be readily accessible and unobstructed. Check the edition your AHJ enforces.
- Fuel and electric shutoff. Discharge must automatically shut off fuel or electric power to the protected equipment, and the reset must be manual. Some fire departments also require gas appliances under the same hood to shut down even if they don't need protection.
- Fire alarm tie-in. Where the building has a fire alarm system, the suppression system generally has to be connected to it. Edwardsville's hood review, for example, includes fuel, electric, and alarm interlocks.
- Makeup air and exhaust fan. Where the system is designed to interlock makeup air, that's tested too. NFPA 96 also calls for a way to start the exhaust fan whenever an appliance under the hood is on.
- Appliance positioning. Wheel stops, floor markings, or another means keep appliances in their design spot. A Texas fire department lists missing positioning as its top reason installs fail inspection.
- Class K extinguisher. One must be within 30 feet of travel from the cooking equipment, with a placard saying to activate the system first. See Class K extinguisher requirements.
Plan Review, Permits, and Acceptance Testing by Region
Missouri has no statewide fire code for restaurants, so the permit path depends on which city or fire district you're in. These are examples from published local documents. Always confirm the current process with your AHJ.
| Area | What we found |
|---|---|
| St. Louis City | 2018 IFC (Ord. 70796). The Fire Department's Bureau of Fire Prevention reviews fire protection system plans with the Building Division. We didn't find a hood-specific permit form. |
| St. Louis County | Dozens of separate fire departments and districts. Creve Coeur FPD lists "Hood Suppression" as a permit type. Clayton (2021 IFC) lists kitchen hood systems among its fire-protection permits and reportedly requires the permit card and approved plans on site. Metro West FPD's 2021 IFC amendment requires wet- and dry-chemical systems to be tested by a discharge of the agent at acceptance. |
| St. Charles County | Mostly 2021 IFC. Wentzville FPD requires construction permits before work starts and occupancy permits before a business operates. O'Fallon FPD's permit application includes a fire suppression system option and a district occupancy permit. The City of St. Charles reportedly won't issue occupancy until its fire inspection is approved. |
| Metro East (IL) | Belleville (2015 IFC) and Edwardsville (2021 IFC) hood permits include plan review, rough-in, interlocks, and an inspector witnessing a wet function test. The Illinois OSFM offers free, voluntary plan review for kitchen suppression systems. |
In Illinois, the state requires kitchen-system installers to hold an OSFM Class 2K license and work for a Class B licensed distributor; confirm current rules with the Office of the State Fire Marshal.
Timeline Factors
Installation time varies a lot. What drives it:
- Whether the hood and duct are new, existing, or being modified.
- How quickly the plans are drawn and how long your AHJ's review takes.
- Lead time on the tank, nozzles, and detection hardware for your system brand.
- Coordination with the gas, electrical, and fire alarm trades for the interlocks.
- Rough-in inspections and scheduling the final acceptance test with the fire official.
- Health department and building occupancy steps, which are separate from the fire permit.
What Affects the Price
The biggest factors are the number of hoods, appliances, and nozzles, tank count, duct length, the system brand, gas versus electric shutoff hardware, whether an old system is being modified or replaced for UL 300, permit and acceptance-test fees, and after-hours work. Compare quotes line by line. Our restaurant fire suppression cost guide covers how.
After installation, the system needs a semiannual kitchen fire suppression inspection, and any future discharge calls for a hood system recharge. Running a truck or trailer instead? See food truck fire suppression. For how the standards fit together, read NFPA 96 vs. NFPA 17A.
Sources: 2015 IFC §904.12 text; Thornton FD commercial cooking requirements (2021 IFC); Intertek NFPA 96 update notice; Lafayette FD on UL 300; FEMA recommended practice; ANSUL R-102 Owner's Guide; Prosper FD top reasons hood systems fail; St. Louis FD Bureau of Prevention; Creve Coeur FPD permit application; Metro West FPD Ord. 121; Wentzville FPD permits; O'Fallon FPD permit application; Belleville FD permit package; Edwardsville fire permit packet; Illinois OSFM plan review services. Requirements vary by jurisdiction; confirm with your local fire official.