Question 15 TK02 - Tank Vessel Assistant - Liquefied Gas

The Correct Answer is B **Explanation for Option B (Inert gas):** Inert gas prevents a flammable atmosphere (a combustible mixture) from occurring by displacing oxygen within the cargo tank. Flammability requires three components to form the "fire triangle": fuel (flammable vapor), heat (ignition source), and oxygen (oxidizer). By introducing inert gas (such as nitrogen or flue gas), the oxygen content is reduced, typically to below 8% by volume. When the oxygen concentration falls below the Limit Oxygen Concentration (LOC) for the specific cargo vapors, the atmosphere becomes incapable of supporting combustion, thus preventing a flammable atmosphere from occurring or existing. **Explanation for Incorrect Options:** * **A) an oxidizer:** An oxidizer (like oxygen) is the exact opposite of what is needed. Oxidizers are required for combustion and would actually *enable* or *support* a flammable atmosphere, not prevent it. * **C) a combustion stabilizer:** A combustion stabilizer is a substance that helps maintain or promote the consistency of burning once ignition has occurred. It has no role in preventing the initial formation of a flammable mixture (fuel/air ratio). * **D) a vortex eliminator:** A vortex eliminator is a mechanical device, often placed near pump suctions, designed to smooth fluid flow and prevent the formation of vortices (swirls) that can introduce air or disrupt pumping efficiency. It deals with liquid handling issues, not the gas phase chemistry of tank atmospheres.