Are there any differences in the pressure rating descriptions for threaded flanges?
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As the title says. According to the company’s standards, for valves and fittings used on pipes with a pressure rating of 150#, if they are connected by flanges, the pressure rating is indicated as 150LB. However, for valves and fittings connected by threads or by socket welding, the pressure rating is indicated as 600LB, 900LB, etc.; in some cases it even reaches 10000LB (such as needle valves with thread connections of 1'' or less). I can understand 150LB, but I don’t understand where 600LB, 900LB, and 10000LB come from
14383 The pressure class of socket-welded pipe fittings is 3000, 6000, or 9000, while the pressure class of threaded pipe fittings is 2000, 3000, or 6000. The pressure rating of this standard is only related to the corresponding wall thickness of the steel pipe (see Appendix A); the correspondence between the two is shown in Table 2.