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BS EN 1092-1 PN25 Flange Dimensions (Table, Sizes and Bolting Data)




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BS EN 1092-1 PN25 flange dimensions define standard sizes, pressure ratings and bolt patterns for pipe flanges used in engineering and piping systems.

This table includes flange diameter, thickness, bore size, bolt circle diameter and bolting data for nominal sizes from DN10 to DN1600.

These flanges are widely used in mechanical, process and pipeline systems where a PN25 pressure rating is required.


DN = Nominal size, D = Outside Diameter, A = Outside Dia of Neck , B1 = Bore of Type 01 & 12 Flange, C1 = Thickness of Plate Flange,
C2 = Thickness of Weld_Neck and Boss Flange , N1 = Dia of Weld Neck , N2 = Dia of Boss ,R = corner Radius, H1 = Length of Boss Flange,
H2 = Length of Weld Neck Flange, H3 = Length of Neck : S = neck thickness

Note: The flange types shown are only a small part of the range covered in BS EN 1092-1.
  • type 05 is a blank flange
  • type13 is a screwed boss flange
  • type 02 is a loose plate flange used with either
      a type 32 weld on plate collar or
      a type 33 lapped pipe end
  • a type 04 flange is a loose flange for use with a
       type 34 a weld-neck collar
  • type 21 is an integral flange
The Facings shown are type B (Raised Face).  Other Facings include:
Type A..Flat:  Type C..Tongue:   Type D..Groove   Type E..Spigot:  :Type F..Recess:   Type G..O-ring Spigot:  Type H.,0-ring Groove:

A typical designation for a flange would be BS EN 1092-1/01B/DN150/PN25/ */S235JR
Key: = Standard No/Flange Type & Face Type / Nominal Size/ Pressure Rating/*/ Material Designation.
* Normally not used.   For 01 type flanges above 600 mm the bore B1 would be specified here .   * for type 11 and 31 the neck thickness (S) is specified here.
An example designation for an flange for an 800mm pipe ...  BS EN 1092-1/01B/DN800/PN25/818/S235JR

This is an extremely simplified note.   To obtain a comprehensive description with the various variations the standards must be used.

How to Use the Flange Dimensions Table

The table below lists standard dimensions for BS EN 1092-1 PN25 flanges. DN refers to nominal pipe size, D is the outside diameter, and other values define flange thickness, bore size and hub geometry.

Bolting data includes bolt circle diameter (K), hole size (L) and number of bolts required for each flange size.

Key Flange Information

  • Standard: BS EN 1092-1
  • Pressure rating: PN25
  • Sizes: DN10 to DN1600
  • Includes flange and bolting dimensions
  • Used in piping, mechanical and process systems

Note : All Dimensions in mm

DN D C1 C2 H1 H2 H3 R A N1 N2 B1 d1 f1 S
10 90 14 14 20 35 6 4 17,2 28 30 18 40 2 1,8
15 95 14 14 20 35 6 4 21,3 32 35 22 45 2 2,0
20 105 14 14 24 38 6 4 26,9 39 45 27,5 58 2 2,3
25 115 16 16 24 38 6 4 33,7 46 52 34,5 68 2 2,6
32 140 18 16 26 40 6 6 42,4 56 60 43,5 78 2 2,6
40 150 18 16 26 42 7 6 48,3 64 70 49,5 88 2 2,6
50 165 20 20 34 48 8 6 60,3 75 84 61,5 102 2 2,9
65 185 22 22 38 52 10 6 76,1 90 104 77,5 122 2 2,9
80 200 24 24 40 58 12 8 88,9 105 118 90,5 138 2 3,2
100 235 26 24 44 65 12 8 114,3 134 145 116 162 2 3,6
125 270 28 26 48 68 12 10 139,7 162 170 141,5 188 2 4,2
150 300 30 28 52 75 12 10 168,3 192 200 170,5 218 2 4,5
200 360 32 30 52 80 16 10 219,1 244 256 221,5 278 2 6,3
250 425 35 32 60 88 18 12 273,0 298 310 276,5 335 2 7,1
300 485 38 34 67 92 18 12 323,9 352 364 327,5 395 2 8,0
350 555 42 38 72 100 20 12 355,6 398 418 359,5 450 2 8,0
400 620 46 40 78 110 20 12 406,4 452 472 411,0 505 2 8,8
450 670 50 46 84 110 20 12 457,0 500 520 462,0 555 2 8,8
500 730 56 48 90 125 20 12 508,0 558 580 513,5 615 2 10,0
600 845 68 58 100 125 20 12 610,0 660 684 616,5 720 2 11,0
700 960 - 46 - 125 20 12 711,0 760 - - 820 2 12,5
800 1085 - 50 - 135 22 12 813,0 864 - - 930 2 14,2
900 1185 - 54 - 145 24 12 914,0 968 - - 1030 2 16,0
1000 1320 - 58 - 155 24 16 1016,0 1070 - - 1140 2 17,5
1200 1530 - - - - - 18 1219,0 - - - 1350 2 -
1400 1755 - - - - - 18 1422,0 - - - 1560 2 -
1600 1975 - - - - - 20 1626,0 - - - 1780 2 -
DN D C1 C2 H1 H2 H3 R A N1 N2 B1 d1 f1 S
Note: in BS EN 1092-1:2002   f1= 2 for all sizes.
In the latest versions of the relevant DIN standard. f1 varies as follow
(DN =< 32 f1 = 1-2, DN 32->250(inc) f1= 1-3, DN 250->500(inc) f1= 1-4, Dn >500 f1= 1-5 )..

Flange Bolting

K = Bolt Circle Diameter, L = Dia Of Bolt Hole,
No = Number of Holes , Size = Size of Bolts

DN K L No Size
mm mm mm - mm
10 60 14 4 M12
15 65 14 4 M12
20 75 14 4 M12
25 85 14 4 M12
32 100 18 4 M16
40 110 18 4 M16
50 125 18 4 M16
65 145 18 8 M16
80 160 18 8 M16
100 190 22 8 M20
125 220 26 8 M24
150 250 26 8 M24
200 310 26 12 M24
250 370 30 12 M27
300 430 30 16 M27
350 490 33 16 M30
400 550 36 16 M33
450 600 36 20 M33
500 660 36 20 M33
600 770 39 20 M36
700 875 42 24 M39
800 990 48 24 M45
900 1090 48 28 M45
1000 1210 56 28 M52
1200 1420 56 32 M52
1400 1640 62 36 M56
1600 1860 62 40 M56
DN K L No Size

Frequently Asked Questions

What is BS EN 1092-1 PN25?

It is a European standard defining flange dimensions and pressure ratings for PN25 pipe flanges.

What does PN25 mean?

PN25 indicates a nominal pressure rating of 25 bar.

What is DN in flange sizes?

DN stands for nominal diameter and represents the pipe or flange size.

Where are PN25 flanges used?

They are used in piping systems, pressure vessels and industrial applications requiring higher pressure ratings.

What is the difference between PN16 and PN25 flanges?

PN25 flanges are designed for higher pressure applications and typically have thicker sections and stronger bolting than PN16 flanges.



See Also