CO2-based gas fire extinguishing systems have been used since the early 1930s. It was welcomed at the time for the lack of alternative solutions. However, over time, problems with its use challenged the technology, and inventors sought to introduce new technology to improve the performance of firefighting systems and solve their problems. Some of the disadvantages of using CO2 gas are as follows:

1. Effect on fire by reducing the concentration of oxygen in the area: By injecting CO2 during a fire, the volume of oxygen gas is greatly reduced and the fire is extinguished. However, this has an immediate effect on people’s health, which in the saturated state will lead to immediate death and in the local state will lead to severe brain damage on the people present at the site. It should be noted that the minimum concentration required for fire extinguishing (Minimum design concentration) with the help of Co2 gas is 34% of the volume of the environment, while the maximum level of concentration for survival of people is 5% of the volume of the environment.

(German Safety and Health standards BGR 134)

Therefore, the ideal fire extinguishing system is a system that does not reduce the amount of oxygen in the environment and does not endanger people’s health if activated.

2. Due to the fact that CO2 gas is under pressure in the capsules, so when leaving and facing the ambient pressure, carbon dioxide will be required to take the temperature of the environment to increase the distance between the molecules. Therefore, during discharge, the ambient temperature will decrease significantly, which will damage the equipment located in the environment.
3. The CO2 fire extinguishing scenario is plotted in such a way that the fire has occurred and in the interval between the detection of the fire by the sensors and the passage of the delay time for people to leave, the equipment located near the fire is heated and then immediately cooled by CO2. . This rapid temperature change changes the appearance of metal objects and deforms them. In many cases, it is necessary to replace the mentioned parts. Therefore, the ideal fire extinguishing system is a system that does not cause a sudden change in ambient temperature.
4. CO2 is a greenhouse gas that destroys the ozone layer and raises the Earth’s temperature. (ODP = 1, GWP = 1) It should be noted that CO2 gas is a measure of the rate of ozone depletion and global warming, so ODP and GWP consider it one. Therefore, the ideal fire extinguishing system is a system that has the least degradation on the ozone layer and the Earth and has a minimum durability in its environment, because with its production and consumption in the world, its concentration in the atmosphere will continuously increase.
5. The use of pressurized cylinders is itself a threat to the environment in which it is installed. On a daily basis, we see the explosion of such capsules in all parts of the world. The cause of their explosion is due to various reasons such as the occurrence of an earthquake, direct exposure to the flame, damage to the valves and its body by accidental manpower and so on. However, there are very strict rules regarding the production of such tanks in various standards.
6. Therefore, in the by-laws approved by the country’s passive defense committee, laws have been passed regarding the non-installation of pressurized tanks near facilities that have a security category. This threat applies not only to places with a security rating, but also to all public places and expensive equipment. Therefore, the ideal fire extinguishing system is a system that does not use such tanks as much as possible.
7. The number of required tanks and related piping occupies one part of the environment and makes another part unusable. This will be more pronounced in places where space is limited, which will cause other problems that may not have seemed so at first. Therefore, the ideal fire extinguishing system will be a system that occupies the least possible space.
8. Due to the fact that CO2 gas has a small molecular mass (its molecular mass is 44), the gas is very volatile and its use as a local application in places that have pores is facing a high risk. If the firebox is not located exactly next to the nozzle, it is very possible to reduce the accuracy of the system.
9. This possibility may lead to the system failing to extinguish the fire, so alternative systems such as the FM-200 (with a molecular mass of 172) have tried to use heavier molecular weight materials to reduce the risk of gas leakage. Find. However, the ideal fire extinguishing system is a system that reduces the risks of gas leakage and leakage to the outside environment to a minimum, or the mechanism of firefighting is changed in such a way that there is no need to prevent oxygen exposure to the fire.

In view of the above, during the last century, the community of engineers and inventors have always sought to find new solutions to increase efficiency and reduce injuries. The result of these efforts has been the emergence of various solutions and the introduction of various technologies over time, some of which are mentioned below.

• Using a combination of other gases such as N2 with CO2 to reduce the destructive effects of CO2 resulting in the production of gases such as IG-54.
• Use of inert gas to reduce the destructive effects of CO2
• Use of halo carbon gases such as Halon 1301 and FM-200

Although halocarbons shone brightly and were much more successful in practice than CO2, their devastating impact on the environment prevented the engineering community from working to reduce the damage. The following is a table comparing the impact of these gases on the environment.