What must be present on an ASME container for it to be filled?

For an ASME (American Society of Mechanical Engineers) container to be filled, it is essential for it to have a legible metal data plate. This plate provides vital information about the container, including specifications such as design pressure, date of manufacture, and the material used. The presence of a data plate ensures that the container meets regulatory safety standards and is appropriate for the intended use. It is a crucial component for identifying the container's capacity and compatibility with the gas being stored, ensuring that proper safety protocols are followed during filling and subsequent operation.

In contrast, while a rubber coating may provide some level of protection against environmental factors, it does not serve the critical purpose of verifying the container's compliance with safety standards. Similarly, a plastic identification tag and an internal pressure gauge are not required for the filling process and do not provide the necessary certification and information mandated by safety regulations. Thus, having a legible metal data plate is fundamental for the safe and compliant operation of an ASME container.