ISO 9624:2019

Thermoplastics piping systems for fluids under pressure - Flange adapters and loose backing flanges - Mating dimensions

This document specifies the mating dimensions for thermoplastic flange adapters and corresponding loose backing flanges intended to be used in thermoplastic piping systems for the conveyance of fluids under pressure. It applies to flange adapters and loose backing flanges for use with pipes with nominal outside diameters (dn) from 16 mm to 2 500 mm and nominal pressures up to 25 bar[1] (PN 25). This document specifies the dimensions of the flange adapters intended to be used for: - butt fusion piping systems; - socket fusion piping systems; - adhesive jointed piping systems. NOTE 1 For specific connections with dimensions (e.g. dn450 or dn630) not covered in this document, or specific equipment (butterfly valves), specific solutions are available on the market. This document is applicable to loose backing flanges made from metal, thermoplastics, or a combination of metal and thermoplastics. This document also provides information on gaskets and gives general recommendations on correct assembling practices. NOTE 2 Industrial applications are not covered by this document. Products intended for industrial application are covered by ISO 15493[1], ISO 15494 or ISO 10931[2]. [1] 1 bar = 0,1 MPa = 105 N/m2.

Systèmes de canalisations thermoplastiques pour fluides sous pression — Collets et brides folles plates — Dimensions de raccordement

General Information

• Status: Published
• Publication Date: 11-Jul-2019
• ICS: 23.040.60 - Flanges, couplings and joints
• Technical Committee: ISO/TC 138/SC 2 - Plastics pipes and fittings for water supplies
• Drafting Committee: ISO/TC 138/SC 2/WG 4 - PE piping systems for water supply
• Current Stage: 9060 - Close of review
• Completion Date: 04-Mar-2030

Relations

• Amended By: ISO 9624:2019/Amd 1:2021 - Thermoplastics piping systems for fluids under pressure - Flange adapters and loose backing flanges - Mating dimensions - Amendment 1
• Effective Date: 28-Aug-2021
• Revises: ISO 9624:1997 - Thermoplastics pipes for fluids under pressure - Mating dimensions of flange adapters and loose backing flanges
• Effective Date: 04-Nov-2015

Overview

ISO 9624:2019 specifies the mating dimensions for thermoplastics flange adapters and corresponding loose backing flanges used in thermoplastic piping systems for the conveyance of fluids under pressure. It covers pipes with nominal outside diameters (DN/OD) from 16 mm to 2 500 mm and nominal pressures up to 25 bar (PN 25). The standard addresses common joint types used in plastic piping: butt fusion, socket fusion and adhesive (bonded) systems, and provides information on gaskets, marking and correct assembly practice.

Key topics and technical requirements

• Mating dimensions: Defines geometrical requirements for flange adapters and mating loose backing flanges to ensure interchangeability and correct fit.
• Scope of application: Applies to flange adapters for butt fusion, socket fusion and adhesive-bonded piping systems for pressure service up to PN 25.
• Size range: Covers DN (nominal outside diameters) from 16 mm up to 2 500 mm, enabling large-diameter thermoplastic connections.
• Materials: Loose backing flanges may be made of metal, thermoplastics, or metal/thermoplastic combinations.
• Compatibility: Uses flange outer diameters and bolt circle values consistent with EN 1092-1 and thread/bolt hole sizes referenced to ISO standards (e.g., ISO 261, ISO 273).
• Gaskets and assembly: Informative annexes provide guidance on gaskets (Annex A), recommended bolt torque application (Annex B), and recommended dimensions for PE100 flange adapters (Annex C).
• Marking: Minimum marking requirements for flange adapters and loose backing flanges to support traceability and correct installation.
• Limitations: Does not cover industrial applications - those are addressed by ISO 15493, ISO 15494 or ISO 10931.

Practical applications and users

ISO 9624:2019 is essential for:

• Pipe and fitting manufacturers producing flange adapters and backing flanges for water and pressure piping systems.
• System designers and engineers who specify thermoplastic piping connections for municipal water, drainage, and non-industrial fluid conveyance.
• Valve and equipment suppliers ensuring compatible flange connections between thermoplastic pipelines and metal equipment.
• Contractors and installers who assemble flanged joints and require guidance on gaskets, bolt torques and correct mating dimensions.
• Specification writers and procurement teams needing normative references for procurement and compliance.

Benefits include improved interchangeability, reliable pressure-tight connections, and reduced assembly errors in thermoplastic piping installations.

Related standards

• EN 1092-1 (steel flanges and joint geometry)
• ISO 4427-3 (PE fittings)
• ISO 7005-1, ISO 261, ISO 273 (threads/bolt sizes)
• ISO 15493, ISO 15494, ISO 10931 (industrial thermoplastic piping standards)

Keywords: ISO 9624:2019, thermoplastics piping systems, flange adapters, loose backing flanges, mating dimensions, DN 2500, PN 25, butt fusion, socket fusion, adhesive bonded, gaskets, bolt torque.

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 9624
Second edition
2019-07
Thermoplastics piping systems for
fluids under pressure — Flange
adapters and loose backing flanges —
Mating dimensions
Systèmes de canalisations thermoplastiques pour fluides sous
pression — Collets et brides folles plates — Dimensions de
raccordement
Reference number
©
ISO 2019
© ISO 2019
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting
on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address
below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: [phone]
Fax: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii © ISO 2019 – All rights reserved

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Symbols and abbreviated terms . 2
5 Dimensions . 3
5.1 General . 3
5.2 Butt fusion systems . 3
5.3 Socket fusion systems . 8
5.4 Adhesive bonded systems . 9
6 Gaskets .12
7 Marking .12
7.1 Minimum required marking of flange adapters .12
7.2 Minimum required marking of loose backing flanges .13
Annex A (informative) Gaskets .14
Annex B (informative) Guidance for the application of the bolt torque .15
Annex C (informative) Recommended dimensions for PE100 flange adapter in relation to
the loose backing flanges PN .17
Bibliography .19
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
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
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).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to the
World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see www .iso
.org/iso/foreword .html.
This document was prepared by Technical Committee ISO/TC 138, Plastics pipes, fittings and valves for
the transport of fluids, Subcommittee SC 2, Plastics pipes and fittings for water supplies.
This second edition cancels and replaces the first edition (ISO 9624:1997), which has been technically
revised.
The main changes compared to the previous edition are:
— increase of dimensions up to 2 500 mm;
— technical consistency with industrial applications standards;
— addition of two informative annexes on gaskets and torque application.
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.
iv © ISO 2019 – All rights reserved

Introduction
This document covers the dimensions of flange adapters and loose backing flanges which are commonly
used in the connection of plastic piping systems to valves, pumping stations or other equipment, and to
pipelines of the same or other material. Some equipment (e.g. butterfly valves) may require specific
designs that are not covered by this document.
This revised version of this document covers dimensions allowing the connection of plastic piping
systems up to DN 2500, to answer the increasing demand of large dimensions on the market.
Flanged joints should be able to transfer long-term axial forces with maintained tightness, which
requires use of suitable components and a correct assembly. This revised version includes informative
annexes addressing joint design and torque application and gives bibliographic references to installation
guidelines which are available on the market.
INTERNATIONAL STANDARD ISO 9624:2019(E)
Thermoplastics piping systems for fluids under
pressure — Flange adapters and loose backing flanges —
Mating dimensions
1 Scope
This document specifies the mating dimensions for thermoplastic flange adapters and corresponding
loose backing flanges intended to be used in thermoplastic piping systems for the conveyance of fluids
under pressure.
It applies to flange adapters and loose backing flanges for use with pipes with nominal outside
1)
diameters (d ) from 16 mm to 2 500 mm and nominal pressures up to 25 bar (PN 25).
n
This document specifies the dimensions of the flange adapters intended to be used for:
— butt fusion piping systems;
— socket fusion piping systems;
— adhesive jointed piping systems.
NOTE 1 For specific connections with dimensions (e.g. d 450 or d 630) not covered in this document, or
n n
specific equipment (butterfly valves), specific solutions are available on the market.
This document is applicable to loose backing flanges made from metal, thermoplastics, or a combination
of metal and thermoplastics.
This document also provides information on gaskets and gives general recommendations on correct
assembling practices.
NOTE 2 Industrial applications are not covered by this document. Products intended for industrial application
[1] [2]
are covered by ISO 15493 , ISO 15494 or ISO 10931 .
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.
ISO 261, ISO general purpose metric screw threads — General plan
ISO 727-1, Fittings made from unplasticized poly(vinyl chloride) (PVC-U), chlorinated poly(vinyl chloride)
(PVC-C) or acrylonitrile/butadiene/styrene (ABS) with plain sockets for pipes under pressure — Part 1:
Metric series
ISO 1452-3, Plastics piping systems for water supply and for buried and above-ground drainage and
sewerage under pressure — Unplasticized poly(vinyl chloride) (PVC-U) — Part 3: Fittings
ISO 4427-3, Plastics piping systems — Polyethylene (PE) pipes and fittings for water supply — Part 3:
Fittings
ISO 7005-1, Pipe flanges — Part 1: Steel flanges for industrial and general service piping systems
5 2
1) 1 bar = 0,1 MPa = 10 N/m .
ISO 15494, Plastics piping systems for industrial applications — Polybutene (PB), polyethylene (PE),
polyethylene of raised temperature resistance (PE-RT), crosslinked polyethylene (PE-X), polypropylene
(PP) — Metric series for specifications for components and the system
ISO 15874-3, Plastics piping systems for hot and cold water installations — Polypropylene (PP) — Part 3:
Fittings
EN 1092-1, Flanges and their joints — Circular flanges for pipes, valves, fittings and accessories, PN
designated — Part 1: steel flanges
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:
— IEC Electropedia: available at http: //www .electropedia .org/
— ISO Online browsing platform: available at http: //www .iso .org/obp
3.1
nominal outside diameter
d
n
specified outside diameter, in millimetres, assigned to a nominal size DN/OD
[3]
Note 1 to entry: The nominal outside diameter d of pipes is given in ISO 161-1 .
n
3.2
nominal size
DN
numerical designation of the size of a flange for reference purposes and only loosely related to
manufacturing dimensions
3.3
nominal pressure
PN
numerical designation used for reference purposes related to the mechanical characteristics of the
component of a piping system
Note 1 to entry: For plastic piping systems conveying water (including flange adapters), the PN symbols
correspond to the allowable operating pressure (PFA) in bar, which can be sustained with water at 20 °C with a
[4]
design basis of 50 years, and based on the minimum design coefficient in accordance with ISO 12162 . For loose
backing flanges, the PN symbol is used to indicate its geometrical characteristics.
4 Symbols and abbreviated terms
d nominal (outside) diameter of connecting pipe and flange adapters, and
n
nominal (inside) diameter of the socket
D outside diameter of loose backing flange
DN size designation of loose backing flange
D bolt hole diameter
D inside diameter of loose backing flange
D pitch circle diameter
2 © ISO 2019 – All rights reserved

D outside diameter of flange adapter head
D outside diameter of flange adapter shank
n number of bolt holes
r radius of shoulder of flange adapter
f
5 Dimensions
5.1 General
Loose backing flanges shall be designated by the relevant PN symbol, in consistency with Table 2 to
Table 4, Table 6 or Table 8 as appropriate.
NOTE 1 The values of the outside diameter D of the loose backing flange and the pitch circle diameter D of the
bolts are taken from EN 1092-1.
NOTE 2 The values of the bolt hole diameter D are taken from series medium in ISO 273.
The inside diameter D of the loose backing flange shall conform to the design of the flange adapter.
Unless otherwise specified, the diameters of the flange adapters as specified in Table 1, Table 5 and
Table 7 shall be suitable with the corresponding loose backing flanges, and therefore comply with
ISO 7005-1 using the appropriate tolerances as given in EN 1092-1.
Flange adapters shall be designed in order to prevent stress concentration at any changes in cross
section. The thickness of the flange adapter face and loose backing flange shall be dependent on the
material used in the manufacture of the adapter and on the nominal pressure (PN) of the piping system
for which it is designed.
Flange adapters according to Table 1 shall be associated with flanges of same d , from Tables 2, 3 or 4
n
as relevant.
NOTE 3 The figures are schematic only, to indicate the relevant dimensions. They do not necessarily represent
manufactured components, e.g. flange adapter with special geometry for connecting butterfly valves.
5.2 Butt fusion systems
The dimensions of the spigot ends shall comply with the relevant pipe system standard, e.g. ISO 4427-3.
All dimensions shall be measured in accordance with Figure 1.
Key
d nominal (outside) diameter of connecting pipe and nominal (inside) diameter of the socket
n
D outside diameter of loose backing flange
D bolt hole diameter
D inside diameter of loose backing flange
D pitch circle diameter
D outside diameter of flange adapter head
D outside diameter of flange adapter shank
r radius of shoulder of flange adapter
f
Figure 1 — Butt fusion systems
For butt fusion systems, the dimensions of the flange adapters shall conform to those given in Table 1.
Table 1 — Flange adapters — Dimensions for butt fusion systems
Nominal outside diame- Outside diameter of Outside diameter of Radius of shoulder of
a b c
ter of pipe and spigot flange adapter head flange adapter shank flange adapter
r
f
d D D
n 4 min 5 min
(+0,5 / −0,5)
16 40 22 3
20 45 27 3
25 58 33 3
32 68 40 3
40 78 50 3
50 88 61 3
63 102 75 4
75 122 89 4
a
The diameter of the spigot shall conform to the relevant product standard.
b
The actual value of D should be as high as possible to ensure fitness for purpose of the assembly. See Annex C for
higher recommended values of D for PE100 flange adapters.
c
D shall be measured in the middle of the radius r .
5 f
4 © ISO 2019 – All rights reserved

Table 1 (continued)
Nominal outside diame- Outside diameter of Outside diameter of Radius of shoulder of
a b c
ter of pipe and spigot flange adapter head flange adapter shank flange adapter
r
f
d D D
n 4 min 5 min
(+0,5 / −0,5)
90 138 105 4
110 158 125 4
125 158 132 4
140 188 155 4
160 212 175 4
180 212 183 4
200 268 232 4
225 268 235 4
250 320 285 4
280 320 291 4
315 370 335 4
355 430 373 6
400 482 427 6
450 585 514 6
500 585 530 6
560 685 615 6
630 685 642 6
710 800 737 8
800 905 840 8
900 1 005 944 8
1 000 1 110 1 047 8
1 200 1 330 1 245 8
1 400 1 540 1 450 8
1 600 1 760 1 650 10
1 800 1 960 1 860 10
2 000 2 170 2 070 10
2 250 2 435 2 320 10
2 500 2 730 2 550 10
a
The diameter of the spigot shall conform to the relevant product standard.
b
The actual value of D should be as high as possible to ensure fitness for purpose of the assembly. See Annex C for
higher recommended values of D for PE100 flange adapters.
c
D shall be measured in the middle of the radius r .
5 f
The dimensions of PN 10 designated loose backing flanges shall conform to those given in Table 2.
Table 2 — PN 10 designated loose backing flange dimensions for butt fusion systems
PN 10 designated loose backing flanges
Nominal
outside Bolts
Outside Inside Pitch circle
diameter of
DN
Bolt hole Screw
diameter diameter diameter
Number
pipe
a
diameter thread
d D D D D n
n min 2 3 1
10 16 90 23 60 14 4 M12
15 20 95 28 65 14 4 M12
20 25 105 34 75 14 4 M12
25 32 115 42 85 14 4 M12
32 40 140 51 100 18 4 M16
40 50 150 62 110 18 4 M16
50 63 165 78 125 18 4 M16
65 75 185 92 145 18 4 M16
80 90 200 108 160 18 8 M16
100 110 220 128 180 18 8 M16
100 125 220 135 180 18 8 M16
125 140 250 158 210 18 8 M16
150 160 285 178 240 22 8 M20
150 180 285 188 240 22 8 M20
200 200 340 235 295 22 8 M20
200 225 340 238 295 22 8 M20
250 250 395 288 350 22 12 M20
250 280 395 294 350 22 12 M20
300 315 445 338 400 22 12 M20
350 355 505 376 460 22 16 M20
400 400 565 430 515 26 16 M24
500 450 670 517 620 26 20 M24
500 500 670 533 620 26 20 M24
600 560 780 618 725 30 20 M27
700 630 895 645 840 30 24 M27
700 710 895 740 840 30 24 M27
800 800 1 015 843 950 33 24 M30
900 900 1 115 947 1 050 33 28 M30
1 000 1 000 1 230 1 050 1 160 36 28 M33
1 200 1 200 1 455 1 260 1 380 39 32 M36
1 400 1 400 1 675 1 470 1 590 42 36 M39
1 600 1 600 1 915
...