The use of a fixed maximum liquid level gauge is an example of what type of procedure in propane filling?

A fixed maximum liquid level gauge is a specific device used in the filling process of propane tanks to monitor and ensure that the tank is not filled beyond its safe liquid capacity. This is a critical safety measure because overfilling a propane tank can lead to dangerous situations such as leaks, spills, or even explosions due to excessive pressure build-up.

Max capacity monitoring involves the continuous monitoring of the liquid level within the tank to adhere to safe operating levels, as indicated by the fixed gauge. This procedure helps ensure compliance with safety regulations, preventing overfilling that could pose a hazard to both the environment and individuals involved in handling and using propane.

The other options relate to different safety or operational protocols but do not specifically address the function of the maximum liquid level gauge in the context of propane filling. This device directly correlates to the ongoing monitoring of liquid levels, making max capacity monitoring the correct categorization for this procedure.