What is a requirement for filling an ASME tank?

The requirement for filling an ASME (American Society of Mechanical Engineers) tank is that the data plate must be legible. The data plate contains critical information about the tank, including its design specifications, maximum allowable working pressure, and other important details regarding safety and operational parameters. A legible data plate ensures that operators can verify the tank's integrity and are aware of its limitations, thereby promoting safe filling practices.

Ensuring that the tank is properly identified and meets the necessary standards is crucial for compliance with safety regulations and for the protection of both personnel and property. Other options involve conditions that do not necessarily pertain to the tank's compliance or safety in filling procedures, making them less relevant in this context.