Flanges are used to connect valves into pipework, making maintenance and removal easier. Their standards vary worldwide and can not always be interchangeable. The tables below show PN flange dimensions to help you identify the standards that you have.
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Nominal pressure |
Flange diameter (mm) |
PCD (mm) |
No. of bolt holes |
Diameter of bolts |
Diameter of holes (mm) |
Diameter of raised face (mm) |
Height of raised face (mm) |
1/2″ nominal bore (DN15) |
PN6 |
80 |
55 |
4 |
M10 |
11 |
40 |
2 |
PN10 |
95 |
65 |
4 |
M12 |
14 |
45 |
2 |
PN16 |
95 |
65 |
4 |
M12 |
14 |
45 |
2 |
PN25 |
95 |
65 |
4 |
M12 |
14 |
45 |
2 |
3/4″ nominal bore (DN20) |
PN6 |
90 |
65 |
4 |
M10 |
11 |
50 |
2 |
PN10 |
105 |
75 |
4 |
M12 |
14 |
58 |
2 |
PN16 |
105 |
75 |
4 |
M12 |
14 |
58 |
2 |
PN25 |
105 |
75 |
4 |
M12 |
14 |
58 |
2 |
1″ nominal bore (DN25) |
PN6 |
100 |
75 |
4 |
M10 |
11 |
60 |
2 |
PN10 |
115 |
85 |
4 |
M12 |
14 |
68 |
2 |
PN16 |
115 |
85 |
4 |
M12 |
14 |
68 |
2 |
PN25 |
115 |
85 |
4 |
M12 |
14 |
68 |
2 |
1 1/4″ nominal bore (DN32) |
PN6 |
120 |
90 |
4 |
M12 |
14 |
70 |
2 |
PN10 |
140 |
100 |
4 |
M16 |
18 |
78 |
2 |
PN16 |
140 |
100 |
4 |
M16 |
18 |
78 |
2 |
PN25 |
140 |
100 |
4 |
M16 |
18 |
78 |
2 |
1 1/2″ nominal bore (DN40) |
PN6 |
130 |
100 |
4 |
M12 |
14 |
80 |
3 |
PN10 |
150 |
110 |
4 |
M16 |
18 |
88 |
3 |
PN16 |
150 |
110 |
4 |
M16 |
18 |
88 |
3 |
PN25 |
150 |
110 |
4 |
M16 |
18 |
88 |
3 |
2″ nominal bore (DN50) |
PN6 |
140 |
110 |
4 |
M12 |
14 |
90 |
3 |
PN10 |
165 |
125 |
4 |
M16 |
18 |
102 |
3 |
PN16 |
165 |
125 |
4 |
M16 |
18 |
102 |
3 |
PN25 |
165 |
125 |
4 |
M16 |
18 |
102 |
3 |
2 1/2″ nominal bore (DN65) |
PN6 |
160 |
130 |
4 |
M14 |
14 |
110 |
3 |
PN10 |
185 |
145 |
4 |
M18 |
18 |
122 |
3 |
PN16 |
185 |
145 |
4 |
M18 |
18 |
122 |
3 |
PN25 |
185 |
145 |
8 |
M18 |
18 |
122 |
3 |
3″ nominal bore (DN80) |
PN6 |
190 |
150 |
4 |
M16 |
18 |
128 |
3 |
PN10 |
200 |
160 |
8 |
M16 |
18 |
138 |
3 |
PN16 |
200 |
160 |
8 |
M16 |
18 |
138 |
3 |
PN25 |
200 |
160 |
8 |
M16 |
18 |
138 |
3 |
4″ nominal bore (DN100) |
PN6 |
210 |
170 |
4 |
M16 |
18 |
148 |
3 |
PN10 |
220 |
180 |
8 |
M16 |
18 |
158 |
3 |
PN16 |
220 |
180 |
8 |
M16 |
18 |
158 |
3 |
PN25 |
235 |
180 |
8 |
M20 |
22 |
162 |
3 |