What are the lower and upper explosion limits for methane?

The lower and upper explosion limits for methane are indeed important parameters in understanding its flammability and potential hazards. The lower explosion limit (LEL) is the minimum concentration of methane in air that can ignite if a spark is introduced, while the upper explosion limit (UEL) is the maximum concentration above which methane cannot ignite because there is insufficient oxygen to support combustion.

For methane, the established lower explosion limit is around 5%, meaning that when the concentration of methane in the air is below this threshold, it cannot ignite. The upper explosion limit sits at approximately 15%, which indicates that concentrations above this value also cannot support combustion. This range is critical for safety in environments where methane may be present, such as in natural gas facilities or wastewater treatment plants.

Recognizing these limits is essential for ensuring safety protocols and monitoring in areas where methane is likely to accumulate. In this case, the correct choice reflects the recognized values of 5% for the lower limit and 15% for the upper limit, making it essential knowledge for professionals working in fields related to gas handling and environmental safety.