BTW, ANSI (e.g. 125#FF flange includes old notations not actually correct. ANSI is a conglomerate organization that recognizes accepted standards. The flange standard is ASME. ASME Class 125 would be more accurate. Look for AWME B16.5 for flange information. The # or pound inserted is wrong. If you are a recent grad having progressed straight through your educatino, the pound references left the ASME standard long before you were born. You will see that explained in front of the standard.
Most people never read codes and standards. Lead, do not follow those people.
John