Clean Agent Fire Suppression Systems: What They Are and Which Agents Are Used

A clean agent fire suppression system is a fixed system that extinguishes fire by discharging a gas into an enclosed space and leaves no water, foam or powder behind. The agent does not conduct electricity, evaporates completely, and its design concentration is calculated below human safety limits. Those three properties make it the standard choice wherever water would do more damage than the fire itself: server rooms, electrical switchgear, archives.

What Does “Clean Agent” Mean?

“Clean agent” is a technical term defined in NFPA 2001: an electrically non-conducting, volatile or gaseous fire extinguishant that does not leave a residue upon evaporation. It is a class, not a brand; FM-200 and Novec 1230 are trade names of agents in that class.

Clean agents fall into two families:

• Chemical (halocarbon) clean agents: FM-200 (HFC-227ea) and FK-5-1-12 (Novec 1230). Stored as a liquid superpressurised with nitrogen, discharged in under 10 seconds, extinguishing mainly by absorbing heat.
• Inert clean agents: IG-541 (Inergen) and IG-55 (Argonite). Made of nitrogen, argon and (in IG-541) a small share of CO2, stored as a gas in high-pressure cylinders, they lower the oxygen level in the room below the point where combustion can continue.

Both families are used in place of Halon 1301, whose production was phased out under the Montreal Protocol. The differences in space, weight and environmental impact between them are covered in detail in our inert gas vs chemical clean agents guide.

Why Is CO2 Not a Clean Agent?

CO2 suppression systems also leave no residue and do not conduct electricity, but the concentrations at which CO2 extinguishes fire are lethal. CO2 is therefore designed to its own standards, outside the clean agent standard, and used in normally unoccupied spaces such as generators, turbines and paint booths. What sets clean agents apart is that they extinguish fire while staying within human safety limits. CO2-specific precautions are summarised in our CO2 safety considerations guide.

Clean Agents Compared

The values are for general comparison; exact figures come from the approval documents of the system used and the project calculation.

Where Are They Used?

Clean agent systems are chosen for enclosed spaces where downtime or water damage would cost more than the fire:

• Data centres and server rooms
• Electrical, switchgear and UPS rooms
• Telecommunications and exchange rooms
• Museum, archive and library stores
• Control rooms, laboratories and hospital technical rooms
• A single electrical panel or machine cabinet, with in-panel suppression systems

When Are They Not Suitable?

Clean agent systems rely on holding a set concentration in an enclosed space for a set time, so they are the wrong choice for open areas that cannot be closed off or rooms whose integrity cannot be achieved. NFPA 2001 also excludes fires involving chemicals that supply their own oxygen (such as cellulose nitrate or gunpowder), reactive metals (such as sodium, potassium, magnesium or titanium) and metal hydrides. These risks need a different suppression method.

How Does a Clean Agent Project Run?

1. Site survey: the protected volume, raised floor and ceiling voids, doors, ventilation and the space available for cylinders are inspected on site.
2. Design: the agent is selected; net volume, design concentration and agent quantity are calculated, and the pipe network is designed with approved hydraulic calculation software. The logic of the calculation is explained in our design concentration and agent quantity guide.
3. Installation: cylinders, pipework, nozzles, detection and the control panel are installed.
4. Room integrity test: a door fan test confirms that the room can hold the agent for the required hold time.
5. Commissioning: detection, alarm, delay and evacuation sequences are tested without discharging agent, and handover documents are prepared.
6. Periodic maintenance: the system is checked at least twice a year, with hydrostatic testing and refilling when needed.

Standards and Regulation

Clean agent systems are mainly designed to NFPA 2001, ISO 14520 and EN 15004; in Türkiye the fire regulation requires design to TS ISO 14520. Components are expected to carry approvals from bodies such as UL, FM, VdS or LPCB. The differences between the standards are covered in our standards and approvals guide, and the gas suppression provisions of Türkiye’s Regulation on Fire Protection of Buildings in our fire regulation guide. For HFC systems such as FM-200, obligations under Türkiye’s Regulation on Fluorinated Greenhouse Gases should also be considered at the design stage.

What Information Is Needed for a Quote?

For a first assessment we need the length, width and height of each protected space; whether there is a raised floor or suspended ceiling; whether the room is normally occupied; where cylinders could be placed; and the existing fire detection system. The factors that drive cost are explained in our gas suppression cost factors guide, and you can request an assessment for your project through the quote form.

To apply this guide to your project, see our gas fire suppression services and every system option on our home page, or contact us through the quote form.

Last updated: 4 November 2026