The minimum and maximum concentrations of a combustible material that will propagate a flame are called?

The minimum and maximum concentrations of a combustible material that will propagate a flame are called?

• A. Flammable limits
• B. Lower explosive limit
• C. Upper explosive limit
• D. Autoignition temperature

Answer: (A)

Flammable limits define the range of fuel-air concentrations that can sustain flame. The lower limit is the minimum concentration needed for flame propagation; below this, the mixture is too lean to burn. The upper limit is the maximum concentration that can still burn; above this, the mixture is too rich to sustain flame. Together, these bounds describe the flammable limits. Terms like lower explosive limit and upper explosive limit refer to the same ends of the range in some texts, while autoignition temperature is a separate property describing the temperature at which ignition occurs without a flame.

Flammable limits define the range of fuel-air concentrations that can sustain flame. The lower limit is the minimum concentration needed for flame propagation; below this, the mixture is too lean to burn. The upper limit is the maximum concentration that can still burn; above this, the mixture is too rich to sustain flame. Together, these bounds describe the flammable limits. Terms like lower explosive limit and upper explosive limit refer to the same ends of the range in some texts, while autoignition temperature is a separate property describing the temperature at which ignition occurs without a flame.