What is the minimum face size required for a non-mercury gage?

The minimum face size required for a non-mercury gauge is specified to ensure that the readings are clear and easily interpreted by operators. A face size of 2-1/4 inches is the standard requirement. This size allows for optimal visibility of the gauge readings, reducing the potential for misreading and ensuring accurate monitoring of the pressure conditions in low-pressure boiler systems.

Using gauges with smaller face sizes could compromise visibility, increasing the risk of operator error, which is particularly critical in the context of boiler safety and operation. Larger gauges, while they may provide clearer readings, are not the minimum requirement specified in regulations, thus confirming that 2-1/4 inches is the appropriate threshold for compliance in this scenario.