According to safety standards, which gas is not considered flammable?

Carbon dioxide is categorized as a non-flammable gas because it does not support combustion. Unlike flammable gases, which can ignite and burn in the presence of an ignition source, carbon dioxide acts primarily as an asphyxiant in high concentrations and is often used as a fire extinguisher, displacing oxygen and thereby inhibiting combustion processes. This characteristic makes it crucial in fire prevention and control, distinguishing it from gases like hydrogen, natural gas, and oxygen, which are known for their flammability and role in facilitating combustion.