The fire extinguishing gas agent (FEGA) is subject to mandatory confirmation of compliance with the requirements of TR EAEU 043/2017 through the declaration process.
Combustion is a complex physicochemical process of transforming the initial substances into combustion products through exothermic reactions, accompanied by the intense release of heat.
If we represent the combustion reaction in a general form, it is a complex physicochemical process based on the chemical reaction of oxidation, capable of progressing with self-acceleration due to the accumulation of released heat.
Fuel + O2 + Q1 -> Combustion Products + CO + Q2
The fuel combines with oxygen from the air, which acts as the oxidizer in this reaction, along with a certain amount of heat that initiates this reaction.
As a result, we obtain combustion products, carbon monoxide, and even more heat released as a result of oxidation.
How can we suppress a fire?
To suppress a fire, we need to remove one of the components from the left side of the equation. We cannot remove the fuel, but we can remove oxygen from the space (this is done by gas displacers). As a result, the oxygen concentration in the area decreases, and the fire can no longer sustain itself, leading to extinguishment. Another method is to remove heat from the ignition source. This is achieved through methods like water-based fire extinguishing or using a gas fire suppression agent that acts as a heat absorber. There is also a third, less obvious method of suppression. We can slow down the reaction by using a certain inhibiting substance to such an extent that the fire will cease. Gas fire suppression involves the use of inert gases and gases that inhibit the combustion reaction to extinguish fires. This type of suppression is considered clean as it does not harm the protected equipment. Based on the above, we can classify all gas fire suppression agents into three main groups:
Gas displacers that reduce the oxygen concentration in the area: CO2, nitrogen (IG-100), argon (IG-01), gas mixtures IG-55, gas mixtures IG-541.
Gas inhibitors that slow down the combustion reaction: Halon 114 B2, Halon 13B1, Halon 125, Halon 227 ea, Halon 23, Halon 318.
Gas coolants that remove heat from the fire source: HFC-5-1-12, Novec 1230.
Most of these gases have a similar set of extinguishing mechanisms. For example, all gas inhibitors remove some heat from the fire source, and the gas coolant also acts as an inhibitor of the combustion process. Gas displacers slightly cool the area, making the fire less prone to spreading.
Inert gases used for fire suppression include nitrogen, argon, and their mixtures. The following gas mixtures are most commonly used:
- 50% nitrogen + 50% argon (sometimes referred to as "argonite").
- 52% nitrogen + 40% argon + 8% carbon dioxide (known as "inergen").
The technology of gas suppression using inert gases is based on the principle of oxygen displacement. When the gaseous fire suppression agent is mixed with air in the area, the oxygen content decreases, and the combustion process is halted. Inert gases do not undergo chemical reactions and effectively extinguish fires.
Nitrogen is a naturally inert gas with excellent extinguishing properties. It has a density similar to that of air and evenly distributes throughout the protected volume. Nitrogen is readily available for production as it is the main component (78.09%) of atmospheric air. It also has the lowest costs for refilling fire suppression modules. Nitrogen is versatile and multifunctional.
Argon is a non-toxic inert gas that constitutes 0.93% of the normal atmospheric air. It does not undergo chemical reactions even in extreme conditions. Due to its inertness, it is also used for fire suppression and extinguishment under very high temperatures. The high specific weight of argon (38% heavier than air) makes it ideal for firefighting near the ground, such as in raised floor environments. Argon has low costs for refilling fire suppression modules.