What happens to a flame when the oxygen concentration is 14% or less?

When the oxygen concentration drops to 14% or less, combustion becomes increasingly difficult, resulting in insufficient oxygen available to support a stable flame. In this environment, flames can become nearly invisible or extinguish entirely, as inadequate oxygen limits the combustion process, which typically relies on a minimum oxygen concentration of around 16% to sustain visible flames.

In such low-oxygen conditions, flames may not produce enough heat or light for them to be seen clearly. This is crucial in understanding fire dynamics and behavior, as recognizing the limits of oxygen concentration is vital for fire safety and response strategies. Knowledge of these conditions helps first responders assess the situation more accurately and implement appropriate measures for fire control and victim rescue.

Other scenarios, such as flames becoming larger or flickering, typically occur under conditions of higher oxygen availability, while color changes in flames might suggest a different range of chemical reactions not solely dependent on oxygen concentration.