ANSI B16.5 is a dimensional standard that provides:
- Standard dimensions for various types and ratings of pipe flanges ( This data is required in order for manufacturers to produce interchangable items)
- Combinations of allowable pressures at various temperatures for various materials (This data allows piping system designers to specify a flange that is strong enough to sustain a pressure at a certain temperature)
The pressure "classes" should not be confused with the pressure/temperature tables...... for example a 300 lb. class flange, made from carbon steel (ASTM A105 material)to the dimensions contained in B16.5 is acceptable for service at 740 psig at 70 F but can be used only to 410 psig at 800 F
