What must portable DOT containers designed to be filled by weight display?

Portable DOT containers designed to be filled by weight must display the water capacity in pounds. This is important because the water capacity represents the maximum amount of liquid that the container can safely hold, which is essential for calculating and ensuring safe filling practices. By indicating the capacity in pounds, users can easily understand the weight of the water equivalent, which is critical when working with propane, a substance that is often measured in terms of weight rather than volume for practical reasons.

Using water capacity in pounds allows for better safety measures when filling the containers, ensuring that they do not exceed the maximum fill limit. This is particularly important in the context of propane, as overfilling can lead to dangerous situations such as pressure buildup and potential leaks. Hence, this regulation is designed to promote safety and proper handling of propane in portable containers.