A boiler furnishing steam air pressures in excess of 15 psi is classified as what?

A boiler that furnishes steam at pressures in excess of 15 psi is classified as a high pressure boiler. This classification is crucial because it affects the design, construction, operation, and regulatory requirements of the boiler. High pressure boilers are typically subject to stricter safety standards and inspections due to the increased risks associated with operating at these elevated pressures.

In contrast, low pressure boilers operate typically at or below 15 psi, while medium pressure boilers operate between low and high pressure thresholds. The designation "standard pressure boiler" is not commonly used in industry classifications. Therefore, the correct classification for a boiler operating above this pressure threshold is high pressure boiler, reflecting the safety and engineering implications of managing steam systems under these conditions.