A mixture of air and gas is considered hazardous when it exceeds what percentage of the lower explosive limit (LEL)?

A mixture of air and gas is considered hazardous when it exceeds 10% of the lower explosive limit (LEL) because this is the concentration at which the atmosphere becomes potentially explosive. The LEL is defined as the lowest concentration of gas or vapor in air that can ignite and lead to an explosion under specific conditions.

When the concentration reaches 10% of the LEL, it signals a significant risk of ignition if an ignition source is present. This percentage acts as a precautionary threshold for safety protocols. Exceeding this level means the mixture is not just flammable, but also poses a serious risk of combustion and explosion in an enclosed or controlled environment.

Understanding this percentage is critical for maintaining safety in environments where gases are present, ensuring proper monitoring and activation of safety measures to prevent incidents.