Gaseous fire suppression is one of several methods that can be used to extinguish fires. There are four different ways that gaseous fire suppression can work to put out a fire, each of which requires different gases. The primary method that gaseous fire suppression uses is the reduction of available oxygen through the introduction of inert gases, though other substances can be used to cool off the local environment, inhibit chemical reactions, and isolate fuel sources. This method of extinguishing fires is typically integrated into automatic fire suppression systems that are associated with valuable or delicate equipment. Many of the substances that are used in these systems can be harmful to people or cause suffocation, so alarm systems are usually integrated to warn people to evacuate the area before any gases are released.
All fire suppression techniques rely on a concept known as fire tetrahedron. This concept refers to the fact that heat, fuel, oxygen, and a chemical reaction are required for fire to exist. Each of these factors can be suppressed by different gases. Some fire suppression systems act on only one of the four components of the fire tetrahedron, though others use multiple gases to increase effectiveness.
There are two main types of gaseous fire suppression systems, each of which works on a different scale. Total flooding systems are designed to fill a particular space with extinguishing gases, such as argon or carbon dioxide, that effectively displace oxygen. With no oxygen to burn, the combustion process is interrupted and the fire can be quickly extinguished.
Other types of gaseous fire suppression systems target a smaller area rather than flooding an entire room. These systems can make use of a variety of different gases and can be somewhat similar in application to manually operated fire extinguishers. Halon is one gas that can interfere with the chemical reaction necessary for combustion. Other substances, such as the halocarbon HFC-227ea, can also be used.
Gaseous fire suppression can pose potential dangers to anyone in the immediate vicinity. Total flooding systems can leave anyone trapped in the area with nothing to breath. These systems can also generate excess pressure, which may cause physical trauma to anyone in the immediate area. Some of the gases used in these systems can also be hazardous if they are inhaled or come into contact with skin. Others decompose into potentially dangerous substances during the process of extinguishing a fire.