What determines the size of the test measure an inspector shall use?

The size of the test measure that an inspector should use is primarily determined by the gallons per minute output of the test device. This is critical because the flow rate governs how much liquid will pass through the measuring device over a specified time period. To ensure accurate measurement and verification of the device's performance, the test measure must be sufficiently sized to capture the flow without overflow, allowing for an effective assessment of the system under normal operating conditions.

Using a test measure that is too small for the flow rate could lead to inaccurate readings or potential spillage, thus failing to accurately reflect the performance of the device being tested. The other factors listed, such as the weight, viscosity, and temperature of the liquid, can influence measurement in certain contexts, but they do not directly dictate the size of the test measure in the same fundamental way that the flow rate does. Understanding this principle helps ensure that accurate verification can be achieved, leading to reliable results in measurement practices.