Question 51Safety & Environmental - 1st Asst/Chief

70% to pass

Which of the following conditions is true concerning flammable liquid vapors with a concentration above the upper explosive limit?

AThe mixture is too lean to burn.
BThe mixture is too rich to burn.
CThe vapor is about to explode.
DConditions are perfect for combustion.
AI Explanation

The correct answer is B) The mixture is too rich to burn. When the concentration of flammable liquid vapors is above the upper explosive limit (UEL), the mixture becomes too rich with fuel to ignite and burn. At this high concentration, there is not enough oxygen present to support combustion, so the vapors will not burn. The other options are incorrect - the mixture is not too lean to burn (A), the vapor is not about to explode (C), and the conditions are not perfect for combustion (D) when the concentration is above the UEL.

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