Are PN10 and PN16 Flanges Compatible? EN 1092-1 Drilling by Nominal Size
Short answer: up to DN150, yes. From DN200, no. Under EN 1092-1, PN10 and PN16 flanges share the same outside diameter, bolt circle and bolting up to DN150, so they bolt to each other. From DN200 the number of bolts, the bolt size or the bolt circle differs.
PN10 and PN16 drilling, DN15 to DN600
Values in mm, from EN 1092-1. D = flange outside diameter, K = bolt circle diameter.
| DN | PN10: D / K / bolts | PN16: D / K / bolts | Compatible? |
|---|---|---|---|
| 15 | 95 / 65 / 4 × M12 | 95 / 65 / 4 × M12 | Yes |
| 20 | 105 / 75 / 4 × M12 | 105 / 75 / 4 × M12 | Yes |
| 25 | 115 / 85 / 4 × M12 | 115 / 85 / 4 × M12 | Yes |
| 32 | 140 / 100 / 4 × M16 | 140 / 100 / 4 × M16 | Yes |
| 40 | 150 / 110 / 4 × M16 | 150 / 110 / 4 × M16 | Yes |
| 50 | 165 / 125 / 4 × M16 | 165 / 125 / 4 × M16 | Yes |
| 65 | 185 / 145 / 8 × M16 * | 185 / 145 / 8 × M16 | Yes, check holes * |
| 80 | 200 / 160 / 8 × M16 | 200 / 160 / 8 × M16 | Yes |
| 100 | 220 / 180 / 8 × M16 | 220 / 180 / 8 × M16 | Yes |
| 125 | 250 / 210 / 8 × M16 | 250 / 210 / 8 × M16 | Yes |
| 150 | 285 / 240 / 8 × M20 | 285 / 240 / 8 × M20 | Yes |
| 200 | 340 / 295 / 8 × M20 | 340 / 295 / 12 × M20 | No: 8 vs 12 bolts |
| 250 | 395 / 350 / 12 × M20 | 405 / 355 / 12 × M24 | No |
| 300 | 445 / 400 / 12 × M20 | 460 / 410 / 12 × M24 | No |
| 350 | 505 / 460 / 16 × M20 | 520 / 470 / 16 × M24 | No |
| 400 | 565 / 515 / 16 × M24 | 580 / 525 / 16 × M27 | No |
| 500 | 670 / 620 / 20 × M24 | 715 / 650 / 20 × M30 | No |
| 600 | 780 / 725 / 20 × M27 | 840 / 770 / 20 × M33 | No |
* DN65 PN10: EN 1092-1 gives 8 holes, but 4-hole PN10 flanges from older DIN practice are still common. The bolt circle is the same, so always state the number of holes when ordering.
What this means in practice
DN15 to DN150
PN10 and PN16 flanges bolt to each other. In this range one flange, valve or fitting can serve both classes, which is why many catalogues list them as "PN10/16".
DN200
The outside diameter and bolt circle are the same, but PN10 has 8 bolts and PN16 has 12. Some valve makers produce dual-drilled bodies that fit both. Otherwise, the flanges must be ordered to the right class.
DN250 and larger
Bolt circle and bolt size both differ. PN10 and PN16 do not bolt together. An adaptor or a custom-drilled flange is needed.
The pressure rule
A joint is only as strong as its weakest part. If a PN16 valve is installed between PN10 flanges, the line must be treated as PN10. The allowable pressure also falls as temperature rises, according to the material group tables in EN 1092-1.
PN16 and PN40
PN16 and PN40 drilling is the same only up to DN80. From DN100, PN40 flanges have a larger outside diameter and bolt circle (DN100 PN40: 235 / 190 / 8 × M20) and do not bolt to PN16.
EN 1092-1 flanges from Yazıcı Endüstri
Yazıcı Endüstri has manufactured flanges and pipe fittings in Istanbul since 1998 and exports to more than 37 countries. We produce EN 1092-1 flanges from PN 2.5 to PN 400 in carbon and stainless steel, including custom drillings and sizes up to DN 3000. See also custom and large-diameter flanges and the flange facing types guide.
Frequently asked questions
Can a PN16 valve be installed between PN10 flanges?
Up to DN150, yes, and the joint is then rated PN10. From DN200 a dual-drilled valve or matching flanges are needed.
Why does DN65 PN10 sometimes have 4 holes and sometimes 8?
Older DIN practice used 4 holes. EN 1092-1 uses 8, the same as PN16. State the number of holes when ordering.
Are PN16 and PN40 flanges compatible?
Only up to DN80.
This guide is for general information. For project decisions, check the current edition of EN 1092-1 and the project specification.