What must be observed in terms of distances measured from container valves and vents?

The correct answer emphasizes that distances measured from container valves and vents must conform to established safety tables. This is critical for ensuring safety in the handling of LP-gas, as these safety tables are based on a wide range of factors, including the type of installation, the amount of gas present, and potential hazard scenarios. By adhering to these established distances, operators can minimize the risks associated with gas leaks, pressure build-up, and other safety concerns. Compliance with these standards is not only a best practice but is often a regulatory requirement designed to protect both personnel and property.

While accessibility and monitoring are important considerations in a safe operating environment, those aspects do not specifically address the crucial factor of safe distances, which are primarily determined by safety guidelines and regulations. Adhering to recognized distance regulations ensures that facilities are designed in a way that mitigates risks associated with LP-gas storage and handling.