Question 63

The Correct Answer is B **Explanation for Option B (Correct Statement):** Option B states, "A hot boiler will continue to generate steam after the fires are secured." This is correct due to the massive heat storage capacity of the boiler structure itself, including the metal drums, tubes, refractories (insulating bricks/materials), and the pressurized hot water. Even after the fuel supply (fires) is completely shut off, the retained heat energy in these components will continue to transfer to the water, causing it to boil and generate steam for a significant period until the system cools down sufficiently. This residual steaming is a critical factor in safe boiler operation and shutdown procedures. **Explanation of Incorrect Options:** **A) Loss of water will not harm a boiler if the water level can be restored.** This statement is incorrect. Severe loss of water, allowing the furnace tubes or crown sheets to become exposed and overheated, can cause permanent damage, deformation, and potential catastrophic failure (rupture or explosion) of the boiler pressure parts, even if the water level is immediately restored afterward. Overheating weakens the metal structure significantly. **C) The water level in a properly operated boiler will not shrink or swell.** This statement is incorrect. "Shrink" (a temporary drop in water level) and "Swell" (a temporary rise in water level) are common phenomena associated with changes in steam demand and firing rate. When steam demand increases or pressure drops, flashing occurs, causing bubbles to expand (swell). Conversely, when firing is suddenly reduced, the heat transfer drops, bubbles collapse, and the apparent water level drops (shrink). These fluctuations are normal and must be carefully managed by the operator. **D) No boiler will continue to generate steam after the fires are secured.** This statement is incorrect. It is the direct opposite of the correct statement (B). As explained above, the stored thermal energy in the boiler metal and refractories ensures that steam generation continues for a period after the heat source is removed.