Which classes of flammable liquids are ONLY allowed to be stored beneath ground level with sprinklers?

The correct choice refers to Class II and Class IIIA flammable liquids, which are regulated due to their potential hazards in storage and handling. Class II flammable liquids have a flash point between 100°F and 140°F, while Class IIIA liquids have a flash point at or above 140°F but below 200°F. Storing these classes of flammable liquids beneath ground level is a safety measure to minimize the risk of ignition and to contain fire hazards effectively. The requirement for sprinklers provides an additional layer of protection, ensuring that if a fire were to occur, it could be suppressed quickly.

This zoning of storage helps mitigate the risk of flammable vapors accumulating at ground level, leading to potentially dangerous situations. The overall goal of these safety protocols is to protect both people and property by adhering to guidelines that reduce the likelihood of incidents involving fire or explosion.