What percentage of oxygen is required for combustion to occur?

Combustion is a chemical reaction that occurs when a fuel reacts with oxygen, producing heat and light. For combustion to take place effectively, a minimum concentration of oxygen in the atmosphere is necessary. The correct percentage of oxygen required for combustion is typically around 15-19%.

This range is significant because below 15%, the mixture becomes too rich in fuel, which inhibits the combustion process. Conversely, if the oxygen concentration rises above 19%, it can lead to more efficient combustion, but levels much higher than this, particularly above 25%, are not practical for most combustion processes, as they may lead to safety hazards and different combustion characteristics.

In summary, the 15-19% range is identified as the critical threshold where combustion can reliably occur, ensuring both the presence of sufficient oxygen and the balance required for combustion to proceed efficiently.