Which of the following pressure class designations is NOT mentioned in ASME B16.5?

The designation of pressure classes in ASME B16.5 specifically outlines the various pressure ratings for flanges and fittings used in piping systems. Within this standard, the commonly referenced pressure classes include 150, 300, 600, 900, 1500, and 2500.

The pressure class designation of 1200 does not appear within the standards defined by ASME B16.5, making it an incorrect choice among the options listed. This standard does not recognize 1200 as a legitimate pressure rating for flanges, thereby distinguishing this particular designation from the ones that are included.

In contrast, the other options—150, 600, and 2500—are explicitly recognized in the ASME B16.5 standard as valid pressure classes. These classes correspond to specific pressure-temperature ratings that are essential for engineers and designers in ensuring they select appropriate components for safe and efficient operation in various industrial applications.

Understanding these classifications is crucial for professionals compelled to adhere to industry standards, as selecting components outside of the specified norms can lead to performance issues and safety hazards in pipeline systems.