ISO 1609:2020

INTERNATIONAL ISO
STANDARD 1609
Second edition
2020-01
Vacuum technology — Dimensions of
non-knife edge flanges
Technique du vide — Dimensions des brides sans guillotine
Reference number
ISO 1609:2020(E)
©
ISO 2020

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ISO 1609:2020(E)

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ISO 1609:2020(E)

Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Dimensions . 2
4.1 General . 2
4.1.1 Dimensions of flanges and collars . 2
Annex A (normative) Linear sealing loads . 7
Annex B (normative) Bores for flanges and required outside tube diameters .9
Bibliography .12
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ISO 1609:2020(E)

Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
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This document was prepared by Technical Committee ISO/TC 112, Vacuum technology.
This second edition cancels and replaces ISO 1609:1986, of which it constitutes a minor revision. The
changes compared to the previous edition are as follows:
— The title has been updated.
— The normative reference has been updated.
— “40” in 4.1.1 has been corrected to “50”.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/ members .html.
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INTERNATIONAL STANDARD ISO 1609:2020(E)
Vacuum technology — Dimensions of non-knife edge flanges
1 Scope
This document specifies the dimensions of non-knife-edge flanges and collars used in vacuum
technology.
The dimensions ensure interchangeability between bolted, clamped and rotatable flanges:
a) whether the assembly be homogeneous (for example, bolted flanges or clamped flanges) or
heterogeneous (for example, bolted flanges assembled with clamped flanges either by means of
bolts or clamps or by means of bolts and rotatable flanges).
b) whether the sealing rings used with the flanges be elastomer O-rings or metal sealing rings,
provided that they are compatible with the linear sealing loads given in Annex A.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
3.1
nominal bore
value intended to both identify the flange and specify the largest practical size of tubing that can be
accommodated by the flange
[SOURCE: ISO 3669:2017, 3.2]
Note 1 to entry: The tables provide a series of nominal bores intended to identify the flanges or collars.
Note 2 to entry: These values follow the progression of the R10 series of preferred numbers (see ISO 3) from
which only the term 12,5 has been eliminated.
Note 3 to entry: The values of nominal bore belonging to the R5 series of preferred numbers (see ISO 3) are as
follows: 10, 16, 25, 40, 63, 100, 160, 250, 400, 630 and 1 000. They correspond to values intended to permit, in the
long term, the adoption of a reduced series of nominal bores.
Note 4 to entry: The nominal bores 63 and 160 given in Tables 1, 2 and 3 correspond to practical diameters of
70 mm (or 65 mm) and 153 mm respectively.
3.2
diameter of bolt holes
C
value for the diameter of bolt holes
Note 1 to entry: C is derived from the bolt diameters, D, as given in ISO 273.
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ISO 1609:2020(E)

3.3
bolt diameter
D
diameter of the bolts
Note 1 to entry: For a flange of given nominal bore, the bolt diameter, D, is the same for both bolted and rotatable
flanges.
3.4
mating face
area in the form of a ring, the surface finish and the flatness of which make the sealing of the joint
possible.
Note 1 to entry: The minimum mating face is defined by diameter E in Table 1 and S in Table 2, and by diameter F
in Tables 1 and 2.
Note 2 to entry: The flange sealing face shall be flat, and no part of the flange shall project in relation to this plane.
3.5
collar width
G
value for the width of the collar onto which the clamp hooks
Note 1 to entry: The value for the width depends on the system of clamps used and should not be greater
than 2,5 mm.
3.6
outside diameter
H
value for the outside diameter of bolted and rotatable flanges
Note 1 to entry: The dimensions given for the outside diameter are compatible with the requirement that the bolt
washers (ISO 887 – small series) shall not project beyond the outer circumference of the flange.
3.7
number of bolt holes
n
value for the number of bolt holes
Note 1 to entry: The linear sealing loads tabulated in Annex A for a given bolt stress are derived from the values
of the number of bolt holes n.
3.8
inner diameter for the contact area of clamps
U
value for the inner diameter for the contact area of clamps
...