What is the time limit for continuous operation for the water mist system supply tank?

• A. 5 min
• B. 10 min
• C. 15 min
• D. 20 min

Answer: (C)

The main concept being tested is how long the water mist system supply tank can run in a single, uninterrupted operation. Fifteen minutes is the standard duration because the tank is sized to sustain the mist system for that period, giving enough time for initial fire knockdown and cooling while crews locate the source, secure power or fuel sources, and arrange replenishment or a backup supply. If the time were shorter, the system could run dry before the fire is controlled, reducing effectiveness and requiring rapid switching or re-supply. A longer duration would necessitate a much larger tank or additional supply arrangements, which isn’t typical for this setup. So the fifteen-minute continuous operation limit reflects a practical balance between tank capacity, system performance, and firefighting workflow.