How long does a valve controlling connections to water supplies and standpipes have to remain open when operated at maximum speed?

The duration that a valve controlling connections to water supplies and standpipes must remain open when operated at maximum speed is five seconds. This requirement is established to ensure that there is a sufficient flow of water established before engaging with the sprinkler system. This five-second timeframe allows the system to stabilize and ensures that adequate pressure and water volume are provided, which is crucial for effective operation.

This duration helps prevent issues that could arise from rapid opening, such as water hammer or system shock, which can occur if the water flow is suddenly introduced too quickly. Establishing a standard time helps technicians ensure reliable operation and maintain system integrity.

The other options suggest shorter or longer durations, which do not align with the established protocols for valve operation in sprinkler systems. Adhering to the five-second rule supports safety and efficiency in emergency situations where standpipe systems are engaged.