Question 38Safety & Environmental - Assistant Engineer
70% to passWhich of the following conditions is true concerning flammable liquid vapors with a concentration above the upper explosive limit?
AThe mixture is too rich to burn.
BConditions are perfect for combustion.
CThe vapor is about to explode.
DThe mixture is too lean to burn.
AI Explanation
The correct answer is A) The mixture is too rich to burn. When the concentration of flammable liquid vapors is above the upper explosive limit (UEL), the mixture is too rich with fuel, meaning there is too much fuel relative to the available oxygen. In this condition, the vapor-air mixture is not within the flammable range and cannot support combustion. The mixture is considered too rich to burn. The other options are incorrect because: B) Conditions are not perfect for combustion when above the UEL, C) The vapor is not about to explode in this condition, and D) The mixture is not too lean to burn, it is too rich.
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