What are the specifications for a miniature boiler regarding its internal diameter (ID) and gross volume?

The specifications for a miniature boiler stipulate that it must have an internal diameter of no more than 16 inches and a gross volume not exceeding 5 cubic feet. This specification aligns with safety and operational standards to ensure the functionality of the boiler does not exceed the defined limits for miniature classifications. Thus, the choice indicating an internal diameter of 16 inches and a gross volume of 5 cubic feet is indeed the one that meets these criteria.

This classification helps differentiate between larger boilers and miniature ones, allowing for specific regulations and safety measures to be applied to smaller units. It ensures that only boilers fitting within these parameters are categorized as miniature, supporting maintenance and operational protocols specific to their size for safety and efficiency.