FM200™ SYSTEM | What is it?

Last Updated: August 13, 2023, by

The FM-200™ Fire Suppression System is a registered trademark of Dupont, and also known as HFC-227ea [Heptafluoropropane], is a halocarbon clean agent, that is waterless, nonexplosive, non-flammable, odorless and a liquified clear gas, that is pressurized and used as a ‘Fire Extinguishant Agent’, rated for Class A, B, and C type fires, providing a Total Flooding Solution. It was introduced in 1993, replacing Halon which was banned due to its impact and ability to deplete the Ozone Layer and contribute to severe Global Warming under the Montreal Protocol on Substances that Deplete the Ozone Layer.

Where is FM200™ Used?

We will mainly find FM-200 Suppression Systems are used in a range of applications, usually protecting the following areas:

  • Data Halls
  • Server Rooms
  • Telecom Roms
  • UPS Rooms
  • Switch Rooms
  • Fuel Pump Rooms
  • Libaries
  • Museums
  • Medical Facilities
  • Industrial Applications
  • Paint Booths
If want to understand what should be checked during the FM-200 System Maintenance see our article 'FM200 SYSTEM | Maintenance Checklist [PDF]'

What does Clean Agent mean?

A Clean agent is described, by NFPA 2001 as “a volatile or gaseous fire extinguishant that is electrically nonconducting and that does not leave a residue upon evaporation”.

We have written an article providing more detail on 'CLEAN AGENTS | What are they, Types & Benefits'

FM-200 Clean Agent vs. Water-Based?

If we look at the types of areas that the systems protect, the main reason for using a Clean Agent Suppression System is that upon any discharge, be it accidental or actual, there is limited risk of damage caused to the equipment and space being protected as it is electrically non-conductive, leaves no residue, water or corrosive materials.

The Clean Agent can be removed and cleaned from the space via the simple means of ventilation.

Whereas with a water-based system, such as a sprinkler or pre-action system, water damage would generally be experienced, and it is a lot slower to respond, meaning an increase in the business downtime, damage to equipment/materials/assets, and an increase of repair costs after the fire.

What are the different names used for FM-200 gas?

The most common name is obviously FM200™, but there are others that we may hear of:

  • FM-200™
  • HFC-227a
  • 1,1,1,2,3,3,3-Heptafluoropropane
  • Heptafluoropropane

How does it work?

FM-200™ is designed to be held as a liquified compressed gas in the bottle/cylinder, once discharged through to the pipework and nozzles, it will change state to vapor due to its low boiling point, where it will absorb heat from the space.

As a fire requires 3 things to start, Fuel, Oxygen & heat, removing the heat will restrict it from starting.

According to NFPA 2001, once a fire has been detected and the FM-200™ released, it should discharge fully into the space, with a maximum discharge time permitted of 10 seconds, which includes putting the fire out [30 seconds for any inert gas].

We have written an article providing more detail on 'How does an FM-200 System Work?'

Part of the design calculation should determine the required height/depth that the gas should be suspended at, for example, 2.2m from the finished floor, to fully protect the combustible space.

The gas should hold this height for a minimum of 15 minutes.

System Types We May Come Across

Depending on the type of space and size, we have generally seen 2 types of systems installed, the full system and a fixed sprayer unit.

Full System

This is your typical system with a floor-mounted bottle, control panel controlling the equipment/gas release, and distribution pipework with nozzles.

Bottles can be supplied purchased as different cylinder size options and installed as an individual cylinder or multiple connections to a manifold.

Fixed Sprayer / Hanging Unit

The fixed sprayer/hanging unit usually consists of a small single bottle that is mounted on a wall or ceiling protecting a small space., using a single nozzle.

FM-200 Advantages and Disadvantages


  • Commonly avaliable,
  • Fast acting,
  • Minimal down time,
  • A smaller amount of agent is needed compared to inert gases, meaning less storage space required,
  • Simple to install,
  • Simple to commission,
  • Clean, so leaves no residue on sensitive equipment like servers and electronics,
  • Designed to be safe and non-toxic, for breathing incase people are in space where activates.


  • Expensive compared to a wet system,
  • Designed to be total flooding system so the complete system will discharge,
  • Enclosure the gas discharges into will need to withstand any peak pressure from the gas realease, this could mean additional structures or pressure releif systems to be installed,
  • Health and Safety considerations for installation,
  • Not completely green and contributes partly to global warming as still has HFC.

Clean Agent Standards

The most common standard that we have come across when using a Clean Agent Gas for Fire Suppression is the NFPA 2001 – Standard on Clean Agent Fire Extinguishing.

The standard covers the requirements for designing, installing, testing, inspecting, approving, operating, and maintaining the systems.

Is FM200™ banned?

No, FM200 is not banned, there is sometimes confusion with Halon, which during the start of 1992, it was instructed that no manufacturing of new Halon was allowed from 1994, under the Montreal Protocol on Substances that Deplete the Ozone Layer. This was due to its environmental impact on the Ozone Layer.

FM200 became one of the world’s leading replacements of Halon for Fire Suppressant and Clean Agent Gases.

Is FM200™ Safe?

Upon exposure to people, it is safe but should be noted one of the Hazards noted is ‘May displace oxygen and cause rapid suffocation’, due to the way it works, being heavier than air.

Components of an FM200™ System

Although the system looks pretty simple, there are quite a few components that will be required to ensure it is working and operating correctly.

  • Signage
  • Bottle Cage/Bottle Rack and Bracketry
  • Pilot Gas Bottle/s [optional]
  • Main Gas Bottle/s
  • Clean Agent Gas
  • Pressure Gauge
  • Pressure Relief Valve
  • Pilot Line
  • Check Valves
  • Hangers and Supports
  • Discharge Header/Manifold
  • Distribution Pipework
  • Pipework Fittings and Connections
  • Discharge Nozzles
  • Control Panel
  • Battery
  • Battery Charger
  • Control Valve/Solinoid
  • Local Door Panel
  • Emergency Release Button
  • Key Switch
  • Sounder/Bells
  • Beacon/Strobe
  • Smoke/Heat Detectors

FM-200 Design and Calculation Method

For an overview of the design, steps, and calculation methods, see our article: ***

FM200™ Fire Suppression system [pdf]

The below shows a high-level example of an FM-200 System with actuators, valves, and pipework.

To download a copy of the below PDF’s – free – click the button below:

FM-200™ Wiring Diagram Graphic

The below diagram details the areas internal and external to the protected space, and an example of what should be included/wired.

Who manufacturers/supplies FM-200™?

There are many manufacturers of FM200, the most common ones we have seen are listed below:

What is the Pressure of an FM-200™ Cylinder?

As cylinder pressures can be varied, it’s best to check with the manufacturer for the specific values.

What other gases are available?

Although the most common, FM-200™ it is not the only option when it comes to using a Clean Agent for Fire Suppression. Other gases available are:

  • Novec™ 1230 [Halocarbon]
  • Inergen [Inert Gas]
  • Nitrogen [Inert Gas]
  • Argonite [Inert Gas]

Room Integrity Testing

Prior to the space being put into operation, that is being protected, there will need to be a ‘Room Integrity’ test carried out to test it for leakage, and thus ensure the gases holding time can be met.

We explain more on Integrity Testing in our article: 'CLEAN AGENT | Room Integrity Requirements'

5 Different Fire Classes A, B, C, D & K

To understand the Fire Classes [A, B & C] that the FM200 gas is applicable for, refer to the below table:

Class of FireDescription / Covering
Class APaper,
Some Plastics
Class BFlammable Liquids such as:
Oils Based Paints,
Flammable Gases
Class CEnergized Electrical Equipment
Electrical Appliances
Any risk of Electric Shock
Class DMetals,
Class KCombustible Cooking Media [Oils and Fats]

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