PN25 flange dimensions to EN 1092-1: flange outside diameter D, bolt-circle diameter K, bolt-hole size, number of bolts and bolt size for Type 11 weld-neck flanges from DN10 through DN350. Includes DN50 (165 mm OD, 4 x M16), DN100 (190 mm bolt circle, 8 x M20) and DN200 (310 mm bolt circle, 12 x M24). The medium-pressure rating between PN16 and PN40. Values cross-checked across two independent reference tables.
PN25 is the EN 1092-1 pressure rating for a nominal 25 bar flange and a common medium-pressure rating for water, steam and process service that sits between PN16 and PN40. The PN number fixes the bolt pattern, so a PN25 DN100 flange from any maker shares the same 235 mm outside diameter, 190 mm bolt circle and eight M20 bolts. The values below are the EN 1092-1 nominal dimensions for the Type 11 raised-face weld-neck flange across the common DN10 to DN350 range, cross-checked across two independent reference tables.
| DN | Flange OD D (mm) | Bolt circle K (mm) | Bolt hole (mm) | No. of bolts | Bolt size |
|---|---|---|---|---|---|
| DN10 | 90 | 60 | 14 | 4 | M12 |
| DN15 | 95 | 65 | 14 | 4 | M12 |
| DN20 | 105 | 75 | 14 | 4 | M12 |
| DN25 | 115 | 85 | 14 | 4 | M12 |
| DN32 | 140 | 100 | 18 | 4 | M16 |
| DN40 | 150 | 110 | 18 | 4 | M16 |
| DN50 | 165 | 125 | 18 | 4 | M16 |
| DN65 | 185 | 145 | 18 | 8 | M16 |
| DN80 | 200 | 160 | 18 | 8 | M16 |
| DN100 | 235 | 190 | 22 | 8 | M20 |
| DN125 | 270 | 220 | 26 | 8 | M24 |
| DN150 | 300 | 250 | 26 | 8 | M24 |
| DN200 | 360 | 310 | 26 | 12 | M24 |
| DN250 | 425 | 370 | 30 | 12 | M27 |
| DN300 | 485 | 430 | 30 | 16 | M27 |
| DN350 | 555 | 490 | 33 | 16 | M30 |
Bolt holes are drilled on the bolt circle K, straddling the centreline and equally spaced. The bolt size is the largest that passes the listed hole: 14 mm holes take M12, 18 mm M16, 22 mm M20, 26 mm M24, 30 mm M27 and 33 mm M30. Up to DN150 the PN25 bolt pattern matches PN40; from DN200 the two diverge, PN25 keeping the smaller bolt circle and bolt size (DN200 is 12 x M24 on a 310 mm circle, against PN40 12 x M27 on 320 mm).
Flange thickness is not tabled here: the published EN 1092-1 thickness columns differ between reference tables at the smaller DN, so a single thickness value cannot be given without ambiguity. Take the flange thickness for a given DN from the controlling EN 1092-1 table or the flange maker’s data sheet.
Two flanges bolt together only when the pressure rating, DN, bolt circle K and bolt pattern all agree, so confirm all four before ordering. A PN25 flange will not mate to an ASME Class flange of the same DN even though the bore is the same — the bolt circle, hole count and bolt size differ. Up to DN150 the PN16, PN25 and PN40 bolt patterns in EN 1092-1 share the same K and holes, so a PN25 flange and a PN40 flange of the same DN up to DN150 are dimensionally interchangeable at the bolt circle; from DN200 the patterns diverge and must be matched to the actual rating. EN 1092-1 also defines the facing (Type B1 raised face is the common PN25 facing) and the flange material group, which set the gasket and bolt grade for the temperature and pressure. The dimensions above are for the Type 11 weld-neck flange; blind, plate and slip-on PN25 flanges to EN 1092-1 share the same D, K, bolt hole, bolt count and bolt size.
Dimensions are nominal EN 1092-1 values and provided for identification and cross-reference. Confirm against the controlling standard and the specific flange maker’s current data sheet before manufacture or procurement.