Which of the following best describes a 'High pressure boiler'?

The correct characterization of a 'High pressure boiler' is that it is outlined as a power boiler by the American Society of Mechanical Engineers (ASME). This definition is crucial because high pressure boilers are typically utilized in industrial applications where they operate above a certain pressure threshold, which is usually defined by regulations and safety standards established by ASME.

The ASME provides guidelines that help ensure safety and efficiency in the operation of these boilers, indicating that they are complex systems designed to handle high pressures and temperatures. It's important for operating personnel to understand these definitions because they inform the requirements for design, construction, and operation of boilers, especially those used in power generation.

Other options suggest characteristics that do not accurately represent high pressure boilers. For example, high pressure boilers operate at a pressure higher than standard thresholds, which contradicts the first option. The third option incorrectly states that high pressure boilers are not used for power generation, as they often are. Lastly, special licensing requirements are typically associated with operating high pressure boilers, which the final option overlooks, as there are stringent regulations surrounding the operation of these boilers to ensure safety and compliance.