Flowmeters indicate water pressure discharged through the nozzle under what condition?

The correct answer highlights that flowmeters accurately indicate water pressure discharged through the nozzle when the hoseline is functioning at its rated capacity. This means that the hoseline is capable of delivering water at the expected maximum flow rate under normal operational conditions.

When the hoseline operates at its rated capacity, the flowmeter can provide a precise reading, reflecting the actual pressure being generated and the flow rate of water being delivered through the nozzle. This ensures that the measurements are reliable and can be effectively utilized for tactical decision-making, such as assessing the effectiveness of firefighting efforts and determining the resources needed.

In contrast, if the hoseline does not function at this level, whether due to obstructions, leaks, or inadequate pump pressure, the readings from the flowmeter may be inaccurate or misleading, which could ultimately affect the firefighting operation's success.