What is the minimum percentage of carbon dioxide needed to extinguish fires in most flammable liquids?

The correct answer is based on the effectiveness of carbon dioxide (CO2) as a fire suppressant for flammable liquids. Fire extinguishment occurs when the concentration of carbon dioxide in the environment reaches a level that can effectively displace oxygen, which is necessary for combustion.

Generally, for CO2 to effectively extinguish fires involving flammable liquids, a minimum concentration of around 34% is necessary. At this concentration, carbon dioxide can effectively smother the fire by displacing oxygen and interrupting the combustion process.

While other percentages listed may provide some level of suppression, they fall short of being universally effective for the majority of flammable liquid fires. Understanding this threshold is crucial for safety and effectiveness in firefighting operations, particularly in environments where flammable liquids are present.