PED is intended to cover equipments or installations to be sold. If you fabricate something on your own and you are not selling it I believe this applies to you.
European Directives are focused to godos to be sold whithin the European Union.
If you have to fully comply with an international standard, openings in pressure parts are covered in chapter 7 of EN 13480-3, the EN piping design code, parallel to 13445-3 that you mentioned (EN pressure vessel design code).
Best,
Those are the material specs, both are carbon Steel: 105 is forged Steel and 216 is casting Steel. It does not have nothing to do with weldability of it is threaded.
For a 8" valve you are probably limited to casting Steel in the general market.
There are advantages and disadvantages, but must...
Do you have to comply with a client spec, CE marking or anything like that in your piping system?
If not, I think it is ok to think that if you drill a smaller hole than the equivalent type13 flange, you should be fine.
I have used type 13 flanges adding a reducer coupling to match my...
