At what pressure is the pump's capacity rated at 70%?

To determine the pressure at which a fire pump's capacity is rated at 70%, it's important to understand the relationship between pressure and flow in fire pumps. Fire pumps are typically tested at various pressures to ensure they can deliver specific flow rates effectively. The capacity rating of a pump at 70% usually implies that it's operating at a pressure level below which it can provide that specific percentage of its total flow capability.

In this case, a pressure of 200 psi is the correct choice because fire pumps are often designed to operate optimally and efficiently at certain pressure levels while maintaining effective flow rates. When a pump operates at this pressure, it achieves a balance that allows it to deliver 70% of its maximum rated capacity, aligning with industry standards and typical performance metrics.

The other pressures listed—150 psi, 250 psi, and 300 psi—likely represent either lower levels where the pump does not perform at 70% capacity effectively or higher levels where flow rates may drop due to increased resistance or friction in the system, thus not aligning with the expected performance metrics for a standard pump capacity rating.