Special Hazard & Clean Agent Systems
For rooms where water would do more damage than the fire: server rooms, archives, switchgear, flammable liquids.
Special hazard systems put out fires with something other than ordinary sprinkler water: a clean agent gas, inert gas, water mist, condensed aerosol, foam, CO2 or dry chemical. Each suits a different risk, and several are in the middle of a regulatory transition. 3M stopped making Novec 1230 at the end of 2025, US rules now push HFC-227ea (FM-200) toward recycled supply, and PFAS-based firefighting foams are being restricted in Canada and most US states. These systems are engineered and installed by authorized distributors, and the decision usually involves your insurer, a fire protection engineer and the authority having jurisdiction.
Systems and products
8 guides · price bands $ to $$$$
Clean Agent System: FK-5-1-12 (formerly 3M Novec 1230)
A fluorinated ketone stored as a liquid that turns to vapour on discharge, floods a sealed room and puts the fire out mainly by absorbing heat. It leaves no residue, which is why it is used in server rooms, archives and control rooms.
Clean Agent System: HFC-227ea (FM-200 and equivalents)
The most widely installed halocarbon clean agent of the past 25 years, used in server and control rooms. It is an HFC, so in the US it falls under the AIM Act phase-down and new rules requiring recycled agent.
Inert Gas Systems (IG-541 Inergen, IG-55 Argonite, IG-100 Nitrogen)
Blends of naturally occurring gases — nitrogen, argon and CO2 — flood a room and lower oxygen to a level that stops combustion but stays survivable for short exposure. There is no PFAS or HFC involved.
Water Mist Systems (e.g. Marioff HI-FOG)
High-pressure systems turn water into very fine droplets that cool the fire and displace oxygen, using far less water than sprinklers. They are used in heritage buildings, data centres, hotels, turbine enclosures and ships.
Condensed Aerosol Generators (Stat-X, FirePro)
Unpressurized canisters hold a solid compound that, when triggered, releases a fine potassium-salt aerosol that interrupts the fire's chemical chain reaction. They are used for electrical cabinets, engine and generator enclosures and battery rooms.
Foam Fire Suppression Systems (Fixed Foam / Foam-Water)
Foam concentrate mixed into water forms a blanket over burning flammable liquids, smothering and cooling the fire. It is used at fuel storage, aircraft hangars, refineries and chemical warehouses.
Carbon Dioxide (CO2) Total Flooding and Local Application Systems
High- or low-pressure CO2 floods an enclosure or blankets a single machine, smothering the fire. It leaves no residue but is lethal at the concentrations used, so it belongs only in normally unoccupied spaces.
Pre-Engineered Dry Chemical Systems (Paint Booths, Fuel Dispensing)
Fixed systems discharge dry chemical powder onto paint spray booths, fuel-dispensing islands and industrial processes. They are common at auto body shops and gas stations.
Before you buy
- Decide what you are protecting first: business continuity of electronics, people in the room, or a flammable-liquid process. The answer usually picks the agent.
- Total-flooding gas systems only work if the room holds the agent. Room integrity (a door-fan test) and sealing penetrations are part of the job, and remodels break it.
- Ask who supplies the agent for recharges over the life of the system, and get it in writing. Agent supply is changing faster than hardware lifespans.
- CO2 total flooding can kill people in the protected space. It belongs in normally unoccupied spaces with lockouts, warning signs and training.
- Many of these hazards still need sprinklers as well. A clean agent system protects the equipment; the building code may still require sprinklers for the building.