ISO 23748:2016

INTERNATIONAL ISO
STANDARD 23748
First edition
2016-10-01
Aerospace series — O-ring grooves —
Dimensions
Série aérospatiale — Gorges pour joints toriques — Dimensions
Reference number
ISO 23748:2016(E)
©
ISO 2016

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ISO 23748:2016(E)

COPYRIGHT PROTECTED DOCUMENT
© ISO 2016, Published in Switzerland
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ii © ISO 2016 – All rights reserved

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ISO 23748:2016(E)

Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Symbols . 1
4 Required characteristics . 2
4.1 Configuration — Dimensions — Tolerances . 2
4.1.1 General. 2
4.1.2 Radial sealing — Rod housing: Configuration code A. 2
4.1.3 Radial sealing — Bore housing: Configuration code B . . 9
4.1.4 Axial sealing for internal pressure: Configuration code C .16
4.1.5 Axial sealing for external pressure: Configuration code D .22
5 Designation .28
6 Drawing presentation .28
6.1 General .28
6.2 Configuration code A .28
6.3 Configuration code B .29
6.4 Configuration code C .29
6.5 Configuration code D .29
Bibliography .30
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ISO 23748:2016(E)

Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
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ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).
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as well as information about ISO’s adherence to the World Trade Organization (WTO) principles in the
Technical Barriers to Trade (TBT) see the following URL: www.iso.org/iso/foreword.html.
ISO 23748 was prepared by ACE/12/1 as EN 3748:2001 and was adopted (without modification
other than those stipulated below) by Technical Committee ISO/TC 20, Aircraft and space vehicles,
Subcommittee SC 10, Aerospace fluid systems and components.
The following are the modifications made in this International Standard:
— reference to ISO 3601-1 size codes in tables;
— correction in Table 13 of value 90,27 to 91,27;
— addition of “static applications” in the title and scope;
— “according to European Standards” was removed in the scope;
— any reference to European Standards were removed.
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INTERNATIONAL STANDARD ISO 23748:2016(E)
Aerospace series — O-ring grooves — Dimensions
1 Scope
This International Standard specifies the dimensions of grooves for use with O-rings for aerospace in
static sealing applications:
— radial sealing: rod or bore mounted O-rings;
— axial sealing: internal or external pressure source.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
There are no normative references in this document.
3 Symbols
b O-ring groove width
d O-ring inside diameter
1
d O-ring section diameter
2
d O-ring groove diameter, rod mounted
3
d bore diameter, rod mounted
4
d rod outside diameter bore mounted
5
d O-ring groove diameter bore mounted
6
d O-ring groove outside diameter, internal pressure
7
d O-ring groove inside diameter, external pressure
8
d rod outside diameter, rod mounted
9
d bore diameter, bore mounted
10
h groove height
R edge radius on groove
r corner radius on groove
1
t housing depth
Z lead-in chamfer length
© ISO 2016 – All rights reserved 1

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ISO 23748:2016(E)

4 Required characteristics
4.1 Configuration — Dimensions — Tolerances
4.1.1 General
Only recommended sizes are given in the tables.
Dimensions and tolerances are in millimetres. Surface roughness values are in micrometres.
4.1.2 Radial sealing — Rod housing: Configuration code A
4.1.2.1 General
This configuration corresponds to radial grooves in static applications, rod mounted. See Figure 1 and
Tables 1 to 7.
Key
1 bore
2 rod
a
See Table 1.
b
Groove diameter d ≤ 50: maximum run-out tolerance Y = 0,025.
3
Groove diameter d > 50: maximum run-out tolerance Y = 0,05.
3
c
No burrs permitted in this area.
Figure 1
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ISO 23748:2016(E)

Table 1
Roughness
R R
a
Surface
max.
continuous with pressure continuous with pressure
pressure variation pressure variation
≤5 MPa >5 MPa ≤5MPa >5 MPa ≤5 MPa >5 MPa ≤5 MPa >5 MPa
Side
3,2 12,5
surfaces
Groove 1,6 1,6 1,6 6,3 6,3 6,3
Inside
1,6 6,3
diameter
Homologous surface 0,8 3,2
Table 2
d b Z r R
2 1
nom. max. min. min. max. min. max. min.
1,80 2,65 2,40 1,1
0,4 0,2
2,65 3,85 3,60 1,5
0,3 0,1
3,55 5,05 4,80 1,8
0,8 0,4
5,30 7,35 7,10 2,7
7,00 9,45 9,20 3,6 1,2 0,8
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ISO 23748:2016(E)

4.1.2.2 Section diameter d = 1,80
2
Table 3
d d d d
1 3 4 9
+0,06
0
a b
Code nom. f7
0
−0,04
A0040 4,00 4,24 7,00 7,00
A0050 5,00 5,27 8,03 8,03
A0060 6,00 6,30 9,06 9,06
A0069 6,90 7,24 10,00 10,00
A0087 8,75 9,12 11,88 11,88
A0106 10,60 11,02 13,78 13,78
A0125 12,50 12,97 15,73 15,73
A0140 14,00 14,54 17,30 17,30
A0160 16,00 16,64 19,40 19,40
A0180 18,00 18,64 21,40 21,40
A0212 21,20 21,94 24,70 24,70
A0236 23,60 24,44 27,20 27,20
A0280 28,00 28,94 31,70 31,70
A0315 31,50 32,54 35,30 35,30
A0355 35,50 36,64 39,40 39,40
A0365 36,50 37,64 40,40 40,40
A0375 37,50 38,64 41,40 41,40
A0387 38,70 39,84 42,60 42,60
A0400 40,00 41,24 44,00 44,00
a
Size code corresponding to the codification of O-rings according to
ISO 3601-1.
b
See ISO 286-2.
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ISO 23748:2016(E)

4.1.2.3 Section diameter d = 2,65
2
Table 4
d d d d
1 3 4 9
+0,07
0
a b
Code nom. f7
0
−0,05
B0053 5,30 5,58 9,72 9,72
B0069 6,90 7,25 11,39 11,39
B0095 9,50 9,90 14,04 14,04
B0112 11,20 11,66 15,80 15,80
B0132 13,20 13,76 17,90 17,90
B0150 15,00 15,56 19,70 19,70
B0170 17,00 17,66 21,80 21,80
B0200 20,00 20,66 24,80 24,80
B0224 22,40 23,16 27,30 27,30
B0265 26,50 27,36 31,50 31,50
B0300 30,00 30,96 35,10 35,10
B0345 34,50 35,56 39,70 39,70
B0387 38,70 39,86 44,00 44,00
B0437 43,70 45,06 49,20 49,20
B0500 50,00 51,46 55,60 55,60
B0560 56,00 57,66 61,80 61,80
B0600 60,00 61,76 65,90 65,90
B0650 65,00 66,86 71,00 71,00
B0710 71,00 73,06 77,20 77,20
B0750 75,00 77,16 81,30 81,30
B0800 80,00 82,26 86,40 86,40
a
Size code corresponding to the codification of O-rings according to
ISO 3601-1.
b
See ISO 286-2.
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ISO 23748:2016(E)

4.1.2.4 Section diameter d = 3,55
2
Table 5
d d d d
1 3 4 9
+0,08
0
a b
Code nom. f7
0
−0,06
C0250 25,00 25,82 31,30 31,30
C0300 30,00 31,02 36,50 36,50
C0355 35,50 36,62 42,10 42,10
C0425 42,50 43,82 49,30 49,30
C0487 48,70 50,12 55,60 55,60
C0545 54,50 56,12 61,60 61,60
C0615 61,50 63,32 68,80 68,80
C0710 71,00 73,02 78,50 78,50
C0800 80,00 82,32 87,80 87,80
C0900 90,00 92,52 98,00 98,00
C1000 100,00 102,82 108,30 108,30
C1120 112,00 115,12 120,60 120,60
C1150 115,00 118,22 123,70 123,70
C1220 122,00 125,32 130,80 130,80
C1320 132,00 135,62 141,10 141,10
C1400 140,00 143,82 149,30 149,30
C1500 150,00 154,12 159,60 159,60
C1600 160,00 164,32 169,80 169,80
C1700 170,00 174,62 180,10 180,10
C1800 180,00 189,92 195,40 195,40
C1900 190,00 195,12 200,60 200,60
C2000 200,00 205,32 210,80 210,80
C2120 212,00 217,62 223,10 223,10
C2240 224,00 229,92 235,40 235,40
C2360 236,00 242,32 247,80 247,80
C2500 250,00 256,62 262,10 262,10
a
Size code corresponding to the codification of O-rings according to
ISO 3601-1.
b
See ISO 286-2.
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ISO 23748:2016(E)

4.1.2.5 Section diameter d = 5,30
2
Table 6
d d d d
1 3 4 9
+0,09
0
a b
Code nom. f7
0
−0,07
D0600 60,00 61,82 70,20 70,20
D0710 71,00 73,02 81,40 81,40
D0800 80,00 82,32 90,70 90,70
D0900 90,00 92,52 100,90 100,90
D1090 109,00 112,02 120,40 120,40
D1120 112,00 115,12 123,50 123,50
D1180 118,00 121,22 129,60 129,60
D1280 128,00 131,52 139,90 139,90
D1360 136,00 139,72 148,10 148,10
D1450 145,00 148,92 157,30 157,30
D1550 155,00 159,22 167,60 167,60
D1650 165,00 169,42 177,80 177,80
D1750 175,00 179,72 188,10 188,10
D1850 185,00 190,02 198,40 198,40
D1950 195,00 200,22 208,60 208,60
D2000 200,00 205,32 213,70 213,70
a
Size code corresponding to the codification of O-rings according to
ISO 3601-1.
b
See ISO 286-2.
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ISO 23748:2016(E)

4.1.2.6 Section diameter d = 7,00
2
Table 7
d d d d
1 3 4 9
+0,11
0
a b
Code nom. f7
0
−0,09
E1090 109,00 112,06 123,40 123,40
E1150 115,00 118,26 129,60 129,60
E1250 125,00 128,46 139,80 139,80
E1360 136,00 139,76 151,10 151,10
E1450 145,00 148,96 160,30 160,30
E1550 155,00 159,26 170,60 170,60
E1650 165,00 169,46 180,80 180,80
E1750 175,00 179,76 191,10 191,10
E1850 185,00 189,96 201,30 201,30
E1900 190,00 195,16 206,50 206,50
E2000 200,00 205,36 216,70 216,70
E2120 212,00 217,66 229,00 229,00
E2240 224,00 229,86 241,20 241,20
E2300 230,00 236,16 247,50 247,50
E2430 243,00 249,46 260,80 260,80
E2500 250,00 256,66 268,00 268,00
E2580 258,00 264,86 276,20 276,20
E2720 272,00 279,26 290,60 290,60
E2800 280,00 287,46 298,80 298,80
E2900 290,00 297,66 309,00 309,00
E3000 300,00 307,96 319,30 319,30
E3150 315,00 323,36 334,70 334,70
E3250 325,00 333,56 344,90 344,90
E3350 335,00 343,86 355,20 355,20
E3450 345,00 354,06 365,40 365,40
E3550 355,00 364,36 375,70 375,70
E3650 365,00 374,56 385,90 385,90
E3750 375,00 384,86 396,20 396,20
E3870 387,00 397,16 408,50 408,50
E4000 400,00 410,46 421,80 421,80
a
Size code corresponding to the codification of O-rings according to
ISO 3601-1.
b
See ISO 286-2.
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ISO 23748:2016(E)

4.1.3 Radial sealing — Bore housing: Configuration code B
4.1.3.1 General
This configuration (not recommended) corresponds to radial grooves in static applications, bore
mounted. See Figure 2 and Tables 8 to 14.
Key
1 rod
2 bore
a
See Table 8.
b
Groove diameter d ≤ 50: maximum run-out tolerance Y = 0,025.
6
Groove diameter d > 50: maximum run-out tolerance Y = 0,05.
6
c
No burrs permitted in this area.
Figure 2
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ISO 23748:2016(E)

Table 8
Roughness
R R
a
Surface
max.
continuous with pressure continuous with pressure
pressure variation pressure variation
≤5 MPa >5 MPa ≤5 MPa >5 MPa ≤5 MPa >5 MPa ≤5 MPa >5 MPa
Side
3,2 12,5
surfaces
Groove 1,6 1,6 1,6 6,3 6,3 6,3
Inside
1,6 6,3
diameter
Homologous surface 0,8 3,2
Table 9
d b Z r R
2 1
nom. max. min. min. max. min. max. min.
1,80 2,65 2,40 1,1
0,4 0,2
2,65 3,85 3,60 1,5
0,3 0,1
3,55 5,05 4,80 1,8
0,8 0,4
5,30 7,35 7,10 2,7
7,00 9,45 9,20 3,6 1,2 0,8
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ISO 23748:2016(E)

4.1.3.2 Section diameter d = 1,80
2
Table 10
d d d d
1 5 6 10
+0,06
0
a b
Code nom. H8
0
−0,04
A0040 4,00 4,29 7,13 4,37
A0048 4,87 5,15 7,99 5,23
A0056 5,60 5,84 8,68 5,92
A0067 6,70 6,86 9,70 6,94
A0080 8,00 8,16 11,00 8,24
A0087 8,75 8,86 11,70 8,94
A0100 10,00 10,06 12,90 10,14
A0118 11,80 11,86 14,70 11,94
A0140 14,00 13,96 16,80 14,04
A0160 16,00 15,96 18,80 16,04
A0180 18,00 17,86 20,70 17,94
A0200 20,00 19,86 22,70 19,94
A0224 22,40 22,16 25,00 22,24
A0250 25,00 24,66 27,50 24,74
A0280 28,00 27,66 30,50 27,74
A0325 32,50 32,06 34,90 32,14
A0365
...