Small animals tend to live shorter lives than larger animals. There are a few theories as to why that is, but the one I believe is most popular is: small animals tend to live shorter lives anyway (because of threats from predators), so there are fewer opportunities to evolve to be long-lived.
The American National Standards Institute (ANSI) Class 150 is a system of dimensional standards for weld neck, threaded, slip-on, lap joint, socket weld and blind flanges. Dimensions for facing, bolts and studs are also included in ANSI Class 150. ANSI Class 150 establishes measures for pipe sizes.
In the interest of standardization, B16.34 and. its companion standard for flanges, ANSI/ASME B16.5, have established eight. pressure classes and many material groups. for process system valves and flanges, respectively. To facilitate product standard-. ization, B16.34 also includes standard.