What chemical is used to propel and charge the foam on a fixed foam hose station?

Nitrogen is commonly used to propel and charge the foam in fixed foam hose stations. Its properties as an inert gas make it highly suitable for this application. Nitrogen is safe to use in fire suppression systems, as it does not support combustion and helps to maintain the integrity of the foam when it is generated and delivered through the system.

In a fixed foam hose station, nitrogen is typically stored in high-pressure cylinders and is released to create the right pressure needed to mix the foam concentrate with water and distribute it effectively. This ensures that the foam can quickly blanket and suppress flammable liquids and fires.

Other gases listed, such as carbon dioxide, argon, and oxygen, do not serve the same purpose in a foam system. Carbon dioxide, while used in some fire suppression systems, is not used for propelling foam due to its potential to displace oxygen in the environment. Argon is less commonly employed in foam applications and can be more expensive and less readily available than nitrogen. Oxygen is not utilized in this manner as it can actually enhance combustion rather than suppress it.