An adjustable automatic intake pressure relief device must be adjustable from what minimum pressure?

The correct answer is based on standards in fire service operations that dictate the minimum pressure range for automatic intake pressure relief devices. An adjustable automatic intake pressure relief device is crucial for ensuring proper system operation and safety as it prevents excessive pressure buildup within the pump.

Setting the device's minimum adjustment at 90 psi provides a sufficient threshold that allows the device to be sensitive enough to relieve pressure when needed while still ensuring the pump operates effectively. This ensures that the pump can handle a variety of operational scenarios without risking damage from excessive pressure.

Options below 90 psi might not provide adequate safety margins for most fire service operations and could lead to unsafe conditions in the system. Thus, 90 psi is the established minimum for such devices to ensure safe and reliable performance.