What happens to flames when the oxygen concentration falls below 15%?

When the oxygen concentration in the environment falls below 15%, combustion processes are significantly impacted. This low level of oxygen is insufficient to sustain most fires, which generally require an atmosphere with at least 16-21% oxygen for effective burning. As a result, flames may extinguish because they no longer have the necessary oxygen to continue the chemical reactions that produce fire.

In a reduced oxygen environment, fuel may not ignite properly, and flames can become weak or go out entirely. Thus, the correct understanding of fire behavior in low oxygen conditions supports the answer. This principle is crucial for firefighting and safety protocols, emphasizing the importance of oxygen levels in fire dynamics.