What does LFL stand for in the context of refrigerant safety?

What does LFL stand for in the context of refrigerant safety?

• A. Lower explosive limit (LEL)
• B. Upper flammability limit (UFL)
• C. Lower flammability limit (LFL)
• D. Autoignition temperature

Answer: (C)

Flammability limits tell you when a vapor in air can ignite. LFL, the lower flammability limit, is the minimum concentration of refrigerant vapor in air that can ignite in the presence of an ignition source. If the vapor concentration is below this, ignition won’t happen; if it’s between the LFL and the upper flammability limit (UFL), ignition is possible (assuming a flame or spark is present). Autoignition temperature is a different concept—it’s the temperature at which the vapor will ignite without any ignition source. So LFL stands for lower flammability limit.

Flammability limits tell you when a vapor in air can ignite. LFL, the lower flammability limit, is the minimum concentration of refrigerant vapor in air that can ignite in the presence of an ignition source. If the vapor concentration is below this, ignition won’t happen; if it’s between the LFL and the upper flammability limit (UFL), ignition is possible (assuming a flame or spark is present). Autoignition temperature is a different concept—it’s the temperature at which the vapor will ignite without any ignition source. So LFL stands for lower flammability limit.