Which device is required if a flowmeter is not used during performance testing?

The correct answer is the gauge stand. In situations where a flowmeter is not utilized for performance testing, a gauge stand serves as a vital tool for accurately measuring pressure. By properly setting up the gauges, operators can determine the pressure readings within different sections of the system, providing essential information about the performance being tested.

Using a gauge stand ensures that the necessary pressure data can still be collected, which can help in assessing the flow characteristics indirectly. This is particularly important in performance testing as it allows for a more comprehensive understanding of how the system is operating without directly measuring the flow rate through a flowmeter.

While a stopwatch can be useful for timing events or intervals during performance tests, it does not provide the essential pressure measurements that a gauge stand can deliver. The flowmeter directly measures flow and therefore would not be needed if the goal is to conduct testing without it. Similarly, a pitot clamp is a device designed to measure flow velocity directly and is not suitable for performance testing in the absence of flow measurement devices like a flowmeter.