What is the acceptable range of gauge magnitude for measurements of 3 psig?

The acceptable range of gauge magnitude for measurements of 3 psig centers around the operational limits of the boiler system and its safety parameters. A properly calibrated gauge is crucial for accurate monitoring during the operation of high-pressure boilers.

The range that includes 3 psig must encompass the actual operating pressure while also including enough margin to ensure safety and functionality. The correct answer is based on the need for a gauge that can accurately measure pressures slightly below and above the operational pressure for monitoring fluctuations.

By selecting a range between 4.5 psig and 6 psig, it allows for safe observation of conditions just beyond operational pressure without compromising measurement accuracy. It also facilitates the operator to anticipate potential increases in pressure that could indicate problems in the system.

In contrast, the other ranges provided do not adequately cover the acceptable monitoring limits related to 3 psig, either falling below or above the necessary thresholds for high-pressure boiler operation, which is why they are not appropriate choices.