. . Flange & Installation Dimensions of Grade PN1.0Mpa Type “A” ,”LT” Concentric Butterfly Valve Size Dia of pipe (do) Dia of flange (D) Dia of center circls (D1) Inner Dia of flange (D3) Dia of projecting hole of flange (D4) Number of bolt ( n) Dia of bolt holes (d) Flange thickness (b*) Mini thickness of pipe (So*) Dimension of valve (B) mm inch 5 2” 50 4 17.5 22 3.5 42