Short answer: ANSUL is a Johnson Controls brand, and its R-102 wet-chemical system is one of the most common restaurant hood systems. ANSUL calls for inspection at least every six months, after any discharge, and immediately after major hood and duct cleaning, by a distributor it has authorized. Send a request and we'll pass it to an independent provider serving your area; ask that provider to confirm its ANSUL training.
What an Ansul System Is
"Ansul system" is how many owners refer to any hood suppression system, whatever the make. Strictly, ANSUL is a fire protection brand owned by Johnson Controls, and its main restaurant product is the R-102. According to the manufacturer, R-102 is a pre-engineered system that uses ANSULEX Low pH Liquid Agent to protect the hood, ducts, plenum, filters, and cooking appliances such as fryers, griddles, range tops, broilers, char-broilers, and woks. It's listed to UL 300, the fire-test standard for commercial cooking systems, and it can be laid out with appliance-specific nozzles or with overlapping nozzles that cover a continuous zone along the line.
If your system is old enough to use dry chemical, it predates UL 300. Our UL 300 compliance guide explains how to tell and when an upgrade is required.
How an Ansul R-102 System Works
- Detection. Fusible links in the hood melt at a set temperature and release tension on a cable to the control unit.
- Release. The control unit fires a cartridge that pressurizes the agent tank. Staff can also start it with the manual pull station.
- Shutoff. Gas or electric power to the cooking equipment shuts off automatically, and it can only be restored by a manual reset.
- Discharge. Agent sprays through nozzles into the plenum, duct, and onto the appliances.
- Suppression. The agent reacts with hot grease to form a foam layer that smothers the fire and helps keep it from reigniting.
Once it discharges, the system is empty until it's recharged. Clean the residue promptly; ANSUL's guide says within 24 hours with warm soapy water while wearing rubber gloves. Our article on what to do when an Ansul system goes off covers cleanup and reopening, and Ansul recharge and repair covers getting the system back in service.
Piranha Basics
PIRANHA is ANSUL's dual-agent system. A wet agent called PRX discharges first, then water follows through the same nozzles, supplied from the building's domestic or sprinkler water line. Manufacturer literature lists PIRANHA-7, -10, and -13 tank sizes (1.5, 2.25, and 3.0 gallons) and claims it uses less agent and cools oil faster than single-agent systems. Those are the manufacturer's claims, not independent test results. Because Piranha depends on a water supply as well as agent, the inspection includes the water side.
Ansul System Inspection Requirements
ANSUL's R-102 owner's guide asks for inspection "at a maximum of 6 month intervals and immediately after major hood and duct cleaning," and says maintenance must be done semi-annually. That lines up with NFPA 96 and with the International Fire Code (2018 IFC §904.12; 2021 IFC §904.13), which require service at least every six months and after activation. The full visit is walked through on our kitchen fire suppression inspection page.
Between visits, ANSUL asks owners to:
- Inspect the system at least monthly.
- Check daily for loose pipes and for missing or grease-covered nozzle caps.
- Confirm the releasing unit hasn't been tampered with and visual seals are intact.
- Keep the pull station unobstructed.
- Keep the tank area between 32°F and 130°F.
- Avoid corrosive or high-alkaline cleaners on fusible links and cables.
- Call the servicing company before changing the appliance layout, so the system can be re-evaluated.
Metal fusible links are replaced at least every six months under NFPA 17A, NFPA 96, and ANSUL's guidance; some code texts set an annual minimum. The R-102 manual also has separate annual and 12-year maintenance sections, and the 12-year work includes a hydrostatic test of the agent tank.
How Long Does an Ansul System Last?
We found no published service life for an R-102. What decides how long one stays in use is maintenance and support, not age alone:
- 12-year hydrostatic testing of agent cylinders, which a tank has to pass to stay in service.
- Parts availability. UL leaves older listings in place, but a fire department in Indiana notes that a "lack of proper replacement parts may mean the UL listing is void."
- Manufacturer support and kitchen changes. NFPA 96 requires a non-UL 300 system to be brought up to UL 300 when cooking oil changes from animal fat to vegetable oil, appliances are moved or replaced, or the manufacturer no longer supports the equipment.
When a system can't be brought back into compliance, the job becomes a replacement. See kitchen fire suppression installation for new systems and upgrades.
Who Can Service an ANSUL System
ANSUL's owner's guide tells owners not to let anyone perform maintenance on an ANSUL system except a distributor that ANSUL has authorized, and ANSUL.com has a distributor locator. STL Kitchen Suppression isn't affiliated with Johnson Controls or any manufacturer, and we don't decide which companies ANSUL authorizes. When a provider contacts you, ask whether it's on ANSUL's distributor list and whether the technician holds current ANSUL training. In the Metro East, Illinois also requires a Class 2K license for anyone servicing a pre-engineered kitchen system; confirm current rules with the Office of the State Fire Marshal.
Other Brands
Requests are accepted for any brand. Whether a given provider services a brand depends on its technicians' manufacturer training.
| Brand | System | Notes (per manufacturer) |
|---|---|---|
| Pyro-Chem | Kitchen Knight II | Wet chemical, tested to UL 300; also a Johnson Controls brand |
| Amerex | KP and Zone Defense (ZD) | Wet chemical, stored pressure; ZD allows appliance moves within its listing; factory-trained distributors install and service |
| Kidde | WHDR | Wet chemical, pre-engineered, listed to UL 300 |
| Buckeye | Kitchen Mister | Listed to UL 300 |
| Badger | Range Guard | Wet chemical, marketed as tested to UL 300 |
| CaptiveAire | CORE and TANK | Hood-integrated systems listed to UL 300; CORE uses electronic detection |
What Affects the Price
For ANSUL and other systems, pricing depends on the number of tanks and nozzles, the model and parts availability, which links, caps, or cartridges are replaced, any discharge cleanup and recharge, travel, and after-hours scheduling. Our guide to restaurant fire suppression costs explains how to compare quotes.
Local Rules Still Apply
The brand doesn't change who enforces the code. St. Louis City enforces the 2018 IFC, many St. Louis County fire districts and cities have moved to the 2021 IFC, and Belleville and Edwardsville in the Metro East have an inspector witness a wet function test when a hood system is new, modified, or upgraded. Check with your fire department or district.
ANSUL, R-102, ANSULEX, and PIRANHA are trademarks of Johnson Controls. Other brand names belong to their owners and are used here only to describe equipment. STL Kitchen Suppression is not affiliated with or endorsed by any manufacturer.
Sources: ANSUL R-102 Owner's Guide; ANSUL R-102 product page; PIRANHA specification; R-102 manual; Lafayette (IN) Fire Dept. on UL 300; Intertek NFPA 96 standards update; IFC §904.12 text; Amerex KP; Pyro-Chem Kitchen Knight II brochure; Kidde WHDR; Buckeye restaurant systems; CaptiveAire CORE spec; Belleville FD permit package. Requirements vary by jurisdiction; confirm with your local fire official.