Question 48Safety & Environmental - Assistant Engineer

The correct answer is B) 1% to 6% by volume. This is the correct answer because the explosive range, also known as the flammable range, of petroleum vapors when mixed with air is typically between 1% and 6% by volume. Within this range, the vapor-air mixture can be ignited and cause an explosion. Concentrations below 1% are too lean to ignite, while concentrations above 6% are too rich to ignite. The other answer choices are incorrect because 0% to 1% is too lean to be explosive, 6% to 12% is too rich, and 12% to 20% is well beyond the flammable range for petroleum vapors.