Thank you for your detailed information on piping and flange fittings!
You say the 108 should be the diameter should be 108* diameter pipe wall thickness, we usually are called DN100, DN100 flange, specific kilograms or need your process, but if your pipe wall is very thick, I suggest you use the socket type flange, flange standard available HG-20595
According to the nominal pressure difference, with nominal size of DN 100 flange
Should pass through the DN100 for piping engineering, engineering pressure PN0.6, PN1.0, PN2.5 and so on the different pressure levels, it should be to choose according to your actual production line.
