ASME IX PQR Pipe diameters

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HelloI couldnt find a codes section so I have entered in here...Please can someone clear up a query have about qualification range for pipe diameter in ASME IX. I want produce a PQR to cover 75mm (3") and 100mm (4") welded in 6G position, carbon steel. Can someone please point me to the right section of the code where it tells me the pipe (dia) required to be tested that will qualifiy the range 3" to 4". i.e if the procedure is qualified using 4" pipe, will this also qualifiy 3" or is the 4" miniumum. I am going dizzy looking at the code..Thankscraigt
Reply:Ok, found it page 148, QW-452.3Now my question is if the qualification is done with a 100mm test piece will that qualify 73mm to unlimited or 100mm to unlimited.Thanks
Reply:The table you mention refers to the range for the welder's qualification, not the procedure.Diameter is not an essential variable according to ASME IX for this type of welding.See tables QW-252 to 269. As far as your question goes in case of a welder's qualification then the range of approval would be 73mm to unlimited.
Reply:Hi TazThank you for you reply.Yes, I was referring to PQR not WPS sorry for now explaining, so I understand by your answer that 100mm test piece would then allow a WPS to be produced with range 73mm to unlimited, I understand.I think I got slightly confused as I have been looking at an existing WPQR which shows a "pipe diameter range" of 80NB to unlimited. Not sure why this has a range on a PQR, shouldnt the range be only shown on the WPS and then perhaps it should be 73mm to unlimited.Like to hear your thoughts on thisThanks
Reply:No. What I said is that if you weld a test piece with a diameter of 100mm you can issue WPSs in whatever diameter you like since the diameter is not an essential variable for the procedure only for the welder.However the certificates for the welders that were tested on 100mm diameter will have a range of approval 73mm to unlimited.Do not get confused with ASME IX, it is a very easy code.Start on the tables on QW-200 to see which are the variables for each process and to which paragraph they refer to. Then move on to the tables on QW-300 to see the variable for the welder's qualification.Otherwise you will get lost, you cannot go through it like like EN standards.
Reply:Thank you TazAppreciate your help on this.Regards