Carbon Dioxide CO2
Gas Suppression System

Carbon Dioxide or CO2 is a colourless, odourless, electrically non-conductive gas, effective as a clean agent inert gas suppression agent. As Carbon Dioxide gas suppression systems pose a potential health and safety risk to humans, you will find Carbon Dioxide used in applications and environments that are most often unoccupied, yet require a highly effective fire extinguishing system. Furthermore, fewer volumes of Carbon Dioxide gas are required to suppress a fire.

Carbon Dioxide co2 connected gas cylinders

Carbon Dioxide gas suppression systems are designed to operate at the equivalent design concentrations as other agents (<15% oxygen). Carbon Dioxide usage in areas normally occupied by humans is unsafe due to the toxicity of CO2 at higher concentrations (>5%)[1] With that, safety devices and personnel training are a necessary requirement.

Suitability of Carbon Dioxide Gas CO2 Suppression

Carbon Dioxide CO2 gas suppression systems are approved for Class A, B and C special hazards and utilised in various industries. This includes: engine rooms, generator rooms, power stations, flammable liquid storage rooms, and large industrial machines. These are places that are usually free of personnel.

Whilst Carbon Dioxide CO2 has a Global Warming Potential (GWP) of 1 and Ozone Depleting Potential (ODP) of 0. However, the CO2 extracted from the atmosphere and used in fire protection systems in Australia is considered to be a “greener” Inert gas.

Carbon Dioxide CO2 conforms to ISO-14520 (Gaseous Fire Extinguishing Systems).

What types of fire is a Carbon Dioxide CO2 gas suppression system suitable for?

Carbon Dioxide Gas Suppression is suitable against Class A, B or C fires. This includes ordinary combustibles such as wood, paper, fabric, and most kinds of trash. Also, where the fuel is a flammable or combustible liquid or where the fuel is a flammable or combustible gas.

How does a Carbon Dioxide CO2 gas suppression system put out a fire?

A normal fire requires 3 things to continue burning, oxygen levels above 15%, fuel and heat. A (Class A, B or C) fire can be suppressed or extinguished by lowering the amount of oxygen in the air within the protected room, using Carbon Dioxide. Once a fire is extinguished and the CO2 has dispersed to safe levels, personnel can assess any fire or smoke damage. In addition, with a gas suppression agent there is little to no clean-up and as a result minimal disruption to business.

Can a Carbon Dioxide CO2 gas suppression system cause harm to humans?

Certainly, 7.5% concentration or above, Carbon Dioxide can cause asphyxiation in humans. For a total flood protection, Carbon Dioxide CO2 gas suppression systems have ~34% Carbon Dioxide CO2 concentrations. Consequently, due to these obvious dangers, the Carbon Dioxide gas suppression systems must have certain safety devices to protect personnel around or near the protected spaces. One of the life safety devices is a pneumatic siren that warns people in the immediate area that Carbon Dioxide will be discharging from the suppression system. Therefore, it is important to properly train all personnel on the dangers of the Carbon Dioxide fire suppression system and evacuate safely if the system is preparing to discharge the Carbon Dioxide to suppress the fire.

Designing Carbon Dioxide CO2 Gas Suppression Systems

Being 1.5 times heavier than air, Carbon Dioxide CO2 can drift and settle into adjacent places outside the protected space. Following that, consideration needs to be made that carbon dioxide collects in pits and hollows below the protected area after a discharge. Additionally, discharges can occur within the protected space and within the Carbon Dioxide container storage areas. Therefore, appropriate measures should be taken to eliminate these cases during the design phase.

Similarly, as with other systems, CO2 gas suppression design is critical to the outcomes of a project. Therefore, project owners should consider the following quick guide for understanding the potential use cases for Carbon Dioxide .

Alternate chemical names

Positive use cases

Negative use cases


For more information about Carbon Dioxide – CO2.