A miniature boiler is defined as having an internal shell diameter of how many inches or less?

A miniature boiler is specifically defined as having an internal shell diameter of 16 inches or less. This classification is significant as it determines regulatory requirements and safety considerations for the design, installation, and maintenance of the boiler. Knowing this definition helps a plumbing contractor ensure compliance with relevant codes and standards when working with or installing miniature boilers. Understanding these parameters contributes to safer practices in the plumbing and heating industry. The dimensions of such equipment play a crucial role in determining the appropriate types of inspections, insurance liabilities, and operational protocols.