Question 237Safety & Environmental - Assistant Engineer

The correct answer is D) the transfer of heat across an unobstructed space. Radiation is a mode of heat transfer that occurs when heat energy is transmitted through an unobstructed space, without the need for a physical medium. This means that radiation can cause a fire to spread by transferring heat across an open space, such as between compartments on a ship, even if there are no liquids or gases flowing between them. The other answer choices describe other mechanisms of fire spread, such as conduction through metal (A), flowing liquids (B), and heated gases through ventilation (C), but they do not directly address the mechanism of heat transfer by radiation, which is the correct explanation for how radiation can cause a fire to spread.