To achieve its rated capacity, how much water should be over the strainer in drafting?

To ensure optimal performance of the strainer during the drafting process, it is essential to have a sufficient depth of water above the strainer. Having 24 inches of water over the strainer provides adequate pressure and flow while preventing the strainer from drawing in air, which would inhibit the suction necessary for effective drafting. This depth helps maintain the required head pressure, allowing the pump to function efficiently without cavitation or other issues that can arise from insufficient water coverage.

The standards set for water depth are based on empirical data and practical fireground experience, indicating that 24 inches below the strainer is a safe and effective level to achieve reliable operation. In contrast, lesser depths may increase the risk of air entering the system, which can compromise water delivery capabilities. Therefore, the correct depth of 24 inches is crucial for maintaining the rated capacity of the equipment while serving effectively in emergency situations.