What is the term for the maximum concentration of vapor in air that can support combustion?

The maximum concentration of vapor in air that can support combustion is referred to as the upper explosive limit (UEL). This term is significant in the context of safety and risk management regarding flammable substances. The UEL represents the highest concentration of combustible vapor in the air above which there is not enough oxygen to sustain combustion.

When the concentration exceeds this limit, there is too much fuel present relative to oxygen, making combustion impossible. Understanding the UEL is essential for safety officers to ensure that environments where flammable materials are present are monitored and controlled to prevent hazardous situations.

The other terms serve different purposes in the study of combustion and flammability. For instance, the lower explosive limit (LEL) identifies the minimum concentration of vapor in the air required to support combustion. The flammable range refers to the span between the LEL and UEL, indicating the concentrations where combustion is possible. The ignition point, on the other hand, refers to the temperature at which a substance can ignite, not its concentration in the air. Understanding these distinctions helps in assessing risks and implementing safety measures properly.