Piping weldneck flange - do you specify schedule

The WN flanges have their ratings reflect their working pressure in relation to temperature. The thickness of the weld neck of a flange or its schedule relatively corresponds to its rating. So the WN flanges are manufactured with their "standard" neck thicknesses already correspond to their ratings.

I always want to see the schedules of the flanges specified on isometric drawings and MTOs, do you think it's over the top ?

Sometimes, we have the WN flanges to be welded to much thinner pipes. For example where we have spec break, would the suppliers bore the necks to match our requirements ?

Dear GPSVN,

We have to specify the wall thickness when we order the WN flange.
The Hub diameter at point of weld is same as pipe dia (O/D) but The Weld Neck bore is to be based on pipe Schedules (I/D). So we have to specify the thickness of continued pipe.

I specified the wall thickness in MTO and Isometrics, in my previous projects.

Sometimes, we have the WN flanges to be welded to much thinner pipes. For example where we have spec break, would the suppliers bore the necks to match our requirements ?

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No. We have machine several of the flange neck to match the thickness of the pipe in the past - joint details can be found in the ASME. Ive mentioned the ASME since the detail needed by the machinist is the responsibility of the piping people to supply. Then somebody from your organization need to coordinate the activity with the qc inspector - he need to sign off both the machining and the welding.