GOST/ГОСТ 12815-80 Standard,Flanges for valves,fittings and pipelines for Pnom from 0,1 to 20 MPa (from 1 to 200 kgf/sqsm) Types Connecting dimensions and dimensions of sealing surfaces Download the PDF    PDF file: GOST 12815 Flanges standard for valves fittings pipelines Pn 0.1 20 MPa Dimesions weight   GOST/ГОСТ standard flange dimension and weight  GOST/ГОСТ