ISO 4427-3:2019

INTERNATIONAL ISO
STANDARD 4427-3
Second edition
2019-08
Plastics piping systems for water
supply, and for drainage and sewerage
under pressure — Polyethylene (PE) —
Part 3:
Fittings
Systèmes de canalisations en plastique destinés à l'alimentation
en eau et aux branchements et collecteurs d'assainissement sous
pression — Polyéthylène (PE) —
Partie 3: Raccords
Reference number
©
ISO 2019
© ISO 2019
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Published in Switzerland
ii © ISO 2019 – All rights reserved

Contents Page
Foreword .v
Introduction .vi
1 Scope . 1
2 Normative references . 2
3 Terms and definitions . 3
4 Symbols and abbreviated terms . 4
5 Material . 4
5.1 PE compound . 4
5.2 Material for non-polyethylene parts . 4
5.2.1 General. 4
5.2.2 Metal parts . 4
5.2.3 Elastomers . 5
5.2.4 Other materials . 5
6 General characteristics . 5
6.1 Appearance . 5
6.2 Design . 5
6.3 Colour . 5
6.4 Electrical characteristics for electrofusion fittings . 5
6.5 Appearance of factory-made joints . 6
6.6 Effect on water quality . 6
7 Geometrical characteristics . 6
7.1 Measurement of dimensions . 6
7.2 Dimensions of electrofusion socket fittings . 6
7.2.1 Diameters and lengths of electrofusion sockets . 6
7.2.2 Wall thickness . 7
7.2.3 Out-of-roundness of the bore of a fitting (at any point) . 8
7.2.4 Spigots . . 8
7.2.5 Other dimensions . 8
7.3 Dimensions of electrofusion saddle fittings . 8
7.4 Dimensions of spigot end fittings . 9
7.4.1 Diameter and length . 9
7.4.2 Wall thickness of the fusion end .12
7.4.3 Wall thickness of the fitting body .12
7.4.4 Other dimensions .12
7.5 Dimensions of socket fusion fittings .12
7.6 Dimensions of fabricated fittings .12
7.7 Design and dimensions of mechanical fittings .12
7.7.1 General.12
7.7.2 Mechanical fittings with polyethylene spigot ends .12
7.7.3 Mechanical fittings with polyethylene electrofusion sockets .12
7.7.4 Threads .13
7.8 Dimensions of loose backing flanges and flange adapters .13
8 Mechanical characteristics .13
8.1 General .13
8.2 Conditioning .13
8.3 Requirements .13
8.4 Retest conditions .15
8.5 Performance requirements .16
9 Physical characteristics .16
9.1 Conditioning .16
9.2 Requirements .16
10 Chemical resistance of fittings in contact with chemicals .17
11 Performance requirements .17
12 Marking .17
12.1 General .17
12.2 Minimum required marking .17
12.3 Fusion system recognition .18
13 Packaging .18
Annex A (normative) Socket fusion fittings .19
Annex B (normative) Fabricated fittings .21
Annex C (informative) Examples of typical terminal connections for electrofusion fittings .28
Annex D (normative) Short-term pressure test method .31
Annex E (normative) Tensile test for fitting/pipe assemblies .33
Bibliography .35
iv © ISO 2019 – All rights reserved

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, fitting 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 4427-3:2007), which has been technically
revised.
The main changes compared to the previous edition are:
— Update of the normative references;
— Technical consistency with ISO 4437-3 (see Reference [1] in the Bibliography).
A list of all parts in the ISO 4427 series can be found on the ISO website.
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.
Introduction
The ISO 4427 series of standards are a set of system standards that specify the requirements for a
piping system and its components when made from polyethylene (PE). The piping system is intended
to be used in buried or above ground applications, for the conveyance of water for human consumption,
raw water prior to treatment, drainage and sewerage under pressure, vacuum sewer systems, and
water for other purposes.
In respect of potential adverse effects on the quality of water intended for human consumption caused
by the products covered by the ISO 4427 series, it does not provide information on the restriction on
the use of products.
NOTE Guidance for assessment of conformity can be found in Reference [2] in the Bibliography.
vi © ISO 2019 – All rights reserved

INTERNATIONAL STANDARD ISO 4427-3:2019(E)
Plastics piping systems for water supply, and for drainage
and sewerage under pressure — Polyethylene (PE) —
Part 3:
Fittings
1 Scope
This document specifies the fittings made from polyethylene (PE) for buried or above ground
applications, intended for the conveyance of water for human consumption, raw water prior to
treatment, drainage and sewerage under pressure, vacuum sewer systems, and water for other
purposes.
NOTE 1 The intended uses include sea outfalls, laid in water and connection between pipes suspended below
bridges.
This document also specifies the test parameters for the test methods referred to in this document.
In conjunction with the other parts of the ISO 4427 series, this document is applicable to PE fittings, to
joints with components of PE or other materials, intended to be used under the following conditions:
1)
a) a maximum allowable operating pressure (PFA) up to and including 25 bar ;
b) an operating temperature of 20 °C as the reference temperature.
NOTE 2 For other operating temperatures, guidance is given in ISO 4427-1:2019, Annex A.
This document covers a range of maximum allowable operating pressures and gives requirements
concerning colours.
NOTE 3 It is the responsibility of the purchaser or specifier to make the appropriate selections from these
aspects, taking into account their particular requirements and installation practices or codes.
This document is applicable to fittings of the following types:
1. fusion fittings;
a. electrofusion fittings;
b. spigot end fittings (for butt fusion using heated tools and electrofusion socket fusion);
c. socket fusion fittings (see Annex A);
2. mechanical fittings;
a. compression fittings;
b. flanged fittings;
3. fabricated fittings (see Annex B).
5 2
1) 1 bar = 0,1 MPa = 10 Pa; 1 MPa = 1 N/mm .
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 7-1, Pipe threads where pressure-tight joints are made on the threads — Part 1: Dimensions, tolerances
and designation
ISO 228-1, Pipe threads where pressure-tight joints are not made on the threads — Part 1: Dimensions,
tolerances and designation
ISO 1133-1, Plastics — Determination of the melt mass-flow rate (MFR) and melt volume-flow rate (MVR)
of thermoplastics — Part 1: Standard method
ISO 1167-1:2006, Thermoplastics pipes, fittings and assemblies for the conveyance of fluids — Determination
of the resistance to internal pressure — Part 1: General method
ISO 1167-3, Thermoplastics pipes, fittings and assemblies for the conveyance of fluids — Determination of
the resistance to internal pressure — Part 3: Preparation of components
ISO 1167-4, Thermoplastics pipes, fittings and assemblies for the conveyance of fluids — Determination of
the resistance to internal pressure — Part 4: Preparation of assemblies
ISO 3126, Plastics piping systems — Plastics components — Determination of dimensions
ISO 4427-1, Plastics piping systems for water supply, and for drainage and sewerage under pressure —
Polyethylene (PE) — Part 1: General
ISO 4427-2, Plastics piping systems for water supply, and for drainage and sewerage under pressure —
Polyethylene (PE) — Part 2: Pipes
ISO 4427-5, Plastics piping systems for water supply, and for drainage and sewerage under pressure —
Polyethylene (PE) — Part 5: Fitness for purpose of the system
ISO 4433-1, Thermoplastics pipes — Resistance to liquid chemicals — Classification — Part 1: Immersion
test method
ISO 4433-2, Thermoplastics pipes — Resistance to liquid chemicals — Classification — Part 2: Polyolefin pipes
ISO 9624, Thermoplastics pipes for fluids under pressure — Mating dimensions of flange adapters and loose
backing flanges Thermoplastics pipes for fluids under pressure — Mating dimensions of flange adapters
and loose backing flanges
ISO 11357-6, Plastics — Differential scanning calorimetry (DSC) — Part 6: Determination of oxidation
induction time (isothermal OIT) and oxidation induction temperature (dynamic OIT)
ISO 12176-1, Plastics pipes and fittings — Equipment for fusion jointing polyethylene systems — Part 1:
Butt fusion
ISO 13951, Plastics piping systems — Test method for the resistance of plastic pipe/pipe or pipe/fitting
assemblies to tensile loading
ISO 13953, Polyethylene (PE) pipes and fittings — Determination of the tensile strength and failure mode of
test pieces from a butt-fused joint
ISO 13954, Plastics pipes and fittings — Peel decohesion test for polyethylene (PE) electrofusion assemblies
of nominal outside diameter greater than or equal to 90 mm
ISO 13955, Plastics pipes and fittings — Crushing decohesion test for polyethylene (PE) electrofusion
assemblies
2 © ISO 2019 – All rights reserved

ISO 13956, Plastics pipes and fittings — Decohesion test of polyethylene (PE) saddle fusion joints —
Evaluation of ductility of fusion joint interface by tear test
ISO 13957, Plastics pipes and fittings — Polyethylene (PE) tapping tees — Test method for impact resistance
ISO 17885, Plastics piping systems — Mechanical fittings for pressure piping systems — Specifications
EN 681-1:1996, Elastomeric seals — Materials requirements for pipe joint seals used in water and drainage
applications — Part 1: Vulcanized rubber
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 4427-1 and the following 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
electrofusion socket fitting
polyethylene (PE) fitting which contains one or more integral heating elements that are capable of
transforming electrical energy into heat to realize a fusion joint with a spigot end or pipe
3.2
electrofusion saddle fitting
polyethylene (PE) fitting which contains one or more integral heating elements that are capable of
transforming electrical energy into heat to realize a fusion joint onto a pipe
3.2.1
tapping tee
electrofusion saddle fitting (top-loading or wraparound) which contains an integral cutter used for
cutting through the wall of the main pipe, which remains in the body of the tapping tee after installation
3.2.2
branch saddle
electrofusion saddle fitting (top-loading or wraparound) which requires an ancillary cutting tool for
drilling the hole in the adjoining main pipe
3.3
spigot end fitting
polyethylene (PE) fitting where the outside diameter of the spigot length is equal to the nominal outside
diameter, d , of the corresponding pipe
n
3.4
socket fusion fitting
polyethylene (PE) fitting where the socket mouth is designed to be fusion-jointed with a spigot end or a
pipe using heated tools
3.5
fabricated fitting
fitting produced from pipe conforming to ISO 4427-2 and/or from injection-moulded fittings in
accordance with this document
3.6
mechanical fitting
fitting, that generally includes a compression part to provide pressure integrity, leaktightness and
resistance to end loads, for assembling polyethylene (PE) pipe to another PE pipe or any other element
of the piping system
Note 1 to entry: The fitting can create a radial compressive force (compression fitting) or an axial compressive
force (flange connection).
Note 2 to entry: A pipe-supporting sleeve providing a permanent support for a polyethylene (PE) pipe to prevent
creep in the pipe wall under radial compressive forces, can be applicable. In some cases, the supporting sleeve
contributes to end load resistance.
Note 3 to entry: The fitting can allow either a dismountable or permanently assembled joint.
Note 4 to entry: The mechanical fitting can be supplied for field assembly or pre-assembled by the manufacturer.
4 Symbols and abbreviated terms
For the purposes of this document, the symbols and abbreviated terms given in ISO 4427-1 apply.
5 Material
5.1 PE compound
The PE compound from which the fittings are made shall be in accordance with ISO 4427-1.
The stress bearing PE parts of injection moulded fittings shall only be made from virgin material.
Non-stress bearing PE parts shall be made from virgin material or own reprocessed material from a
compound with the same MRS or a mixture of both materials.
NOTE Since PE 40 is not commonly used for pressure applications, it is the intention of ISO/TC 138/SC 2 to
withdraw all references to this compound at the next revision of the ISO 4427 series (all parts).
5.2 Material for non-polyethylene parts
5.2.1 General
The materials and constituent elements used in making the fitting (including elastomers and any metal
parts) shall be as resistant to the external and internal environments as the other elements of the piping
system and shall have a life expectancy under the following conditions at least equal to that of the PE
pipe conforming to ISO 4427-2 with which they are intended to be used:
a) during storage;
b) under the effect of the fluids being conveyed;
c) with respect to the service environment and operating conditions.
Other materials used in fittings and in contact with the PE pipe (e.g. greases) shall not adversely affect
the pipe performance or initiate stress cracking.
5.2.2 Metal parts
All parts susceptible to corrosion shall be adequately protected, provided this is necessary for durability
and function of the system.
4 © ISO 2019 – All rights reserved

When dissimilar metallic parts are used which may be in contact with moisture, appropriate actions
shall be taken to avoid galvanic corrosion.
5.2.3 Elastomers
Elastomeric materials used for the manufacture of seals shall conform to EN 681-1.
5.2.4 Other materials
Greases or lubricants shall not exude on to the fusion areas and shall not affect the long-term
performance of the pipes and fittings nor have any adverse effect on the quality of the water.
6 General characteristics
6.1 Appearance
When viewed without magnification, the internal and external surfaces of the fitting shall be smooth,
clean and free from scoring, cavities and other surface defects such as would prevent conformity of the
fitting to this document.
6.2 Design
The design of the fitting shall be such that, when assembling the fitting onto the pipe or other
components in accordance with the manufacturer's recommendations, the electrical coils and/or seals
are not displaced.
6.3 Colour
The PE part of fitting shall be either black or blue. For fabricated fittings, the colour characteristics of
pipes shall be in accordance with ISO 4427-2.
The blue colour is intended for the conveyance of water for human consumption only.
For above-ground installations, all components other than black should be protected from direct UV light.
6.4 Electrical characteristics for electrofusion fittings
The electrical protection that shall be provided by the fusion process depends on the voltage and the
current used and on the characteristics of the electricity power source.
For voltages greater than 25 V, direct human contact with energized parts shall not be possible when the
fitting is in the fusion cycle during assembly in accordance with the instructions of the manufacturers
of the fittings and of the assembly equipment, as applicable.
NOTE 1 The fitting during the fusion process is part of an electrical system as defined in EN 60335–1,
HD 60364–1, and IEC 60449 (References [3], [4] and [5] in the Bibliography).
The tolerance on the electrical resistance of the fitting at 23 °C shall be stated by the manufacturer. The
resistance shall be between nominal resistance (−10 %) and nominal resistance (+10 %) + 0,1 Ω.
NOTE 2 0,1 Ω is the assumed value of the contact resistance.
The surface finish of the terminal pins shall allow a minimum contact resistance in order to satisfy the
resistance tolerance requirements.
NOTE 3 See Annex C for the examples of typical electrofusion terminal connections.
6.5 Appearance of factory-made joints
The internal and external surfaces of the pipe and fitting after fusion jointing, examined visually
without magnification, shall be free from melt exudation outside the confines of the fitting apart from
that which may be declared acceptable by the fitting manufacturer or used as a fusion marker.
There shall be no wire movement leading to short circuiting when the electrofusion fittings are jointed
in accordance with the manufacturer’s instructions. There shall be no excessive creasing of the internal
surfaces of the adjoining pipes or spigots.
6.6 Effect on water quality
For fittings to be used in contact with water intended for human consumption, see ISO 4427-1.
7 Geometrical characteristics
7.1 Measurement of dimensions
The dimensions of the fittings shall be measured in accordance with ISO 3126. In case of dispute, the
measurement of dimensions shall be made not less than 24 h after manufacture and after conditioning
for at least 4 h at (23 ± 2) °C.
Indirect measurement at the stage of production is allowed at shorter time periods, provided that
evidence is shown of correlation.
7.2 Dimensions of electrofusion socket fittings
7.2.1 Diameters and lengths of electrofusion sockets
When measured in accordance with 7.1, the diameters and lengths of electrofusion sockets (see Figure 1)
shall be in accordance with Table 1.
Key
D “mean inside diameter in the fusion zone” measured in a plane parallel to the plane of the mouth at a distance
of L + 0,5L
3 2
D bore, which is the minimum diameter of the flow channel through the body of the fitting where
D ≥ (d – 2e )
2 n min
L “design penetration depth” of the pipe or male end of a spigot fitting (in case of a coupling without stop, it is
not greater than half the total length of the fitting)
L heated length within a socket as declared by the manufacturer to be the nominal length of the fusion zone
L distance between the mouth of the fitting and the start of the fusion zone as declared by the manufacturer to
be the nominal unheated entrance length of the fitting where L shall be ≥ 5 mm
Figure 1 — Dimensions of electrofusion sockets
6 © ISO 2019 – All rights reserved

Table 1 — Electrofusion socket dimensions
Dimensions in millimetres
Nominal diameter Depth of penetration Fusion zone
of the fitting
d L L L
n 1,min 1,max 2,min
20 25 41 10
25 25 41 10
32 25 44 10
40 25 49 10
50 28 55 10
63 31 63 11
75 35 70 12
90 40 79 13
110 53 82 15
125 58 87 16
140 62 92 18
160 68 98 20
180 74 105 21
200 80 112 23
225 88 120 26
250 95 129 33
280 104 139 35
315 115 150 39
355 127 164 42
400 140 179 47
450 155 195 51
500 170 212 56
560 188 235 61
630 209 255 67
710 220 280 74
800 230 300 82
The mean inside diameter of the fitting in the middle of the fusion zone (see D in Figure 1) shall be not
less than d .
n
The manufacturer shall declare the actual minimum and maximum values of D and determine their
suitability for joint assembly and check the fitness for purpose of the fitting by testing in accordance
with ISO 4427-5.
In the case of a fitting having sockets of differing nominal diameters, each one shall conform to the
requirements for the nominal diameter of the corresponding component.
7.2.2 Wall thickness
In order to prevent stress concentrations, any changes in wall thickness of the fitting body shall be
gradual.
a) The wall thickness of the body of the fitting at any point, E, shall be greater than or equal to e for
min
the corresponding pipe at any part of the fitting located at a distance beyond a maximum of 2L /3
from all entrance faces if the fitting and the corresponding pipe are made from a polyethylene
having the same MRS.
If the fitting is produced from a polyethylene having an MRS that is different from that of the
corresponding pipe, the relationship between the wall thickness of the fitting, E, and the pipe, e ,
min
shall be in accordance with Table 2.
Table 2 — Relationship between pipe and fitting wall thickness
Material
Relationship between fitting wall thickness, E,
and pipe wall thickness, e
Pipe Fitting min
PE 80 PE 100 E ≥ 0,8e
min
PE 100 PE 80 E ≥ 1,25e
min
b) In the case of a wall thickness design different from that according to a), fittings and associated
fusion joints shall additionally meet the performance requirements given in 8.5.
7.2.3 Out-of-roundness of the bore of a fitting (at any point)
When a fitting leaves the site of the manufacturer, the out-of-roundness of the bore of a fitting at any
point shall not exceed 0,015d .
n
7.2.4 Spigots
For fittings that contain spigot outlets (e.g. electrofusion equal tee with spigotted branch), the
dimensions of the spigot shall be according to 7.4.
NOTE For technical and design reasons, the shape of the minimum bore cross-section area can be different
from the one of spigot fittings as given in 7.4.
7.2.5 Other dimensions
The dimensional characteristics appropriate to each manufacturer, such as the overall dimensions or
mounting dimensions, shall be specified in a technical file.
In the case of a coupling without an internal stop or with a removable centre register, the geometry of
the fitting shall allow the penetration of the pipe through the fitting.
7.3 Dimensions of electrofusion saddle fittings
Outlets from tapping tees and branch saddles shall have spigots in accordance with 7.4 or electrofusion
sockets in accordance with 7.2.
The manufacturer shall specify the overall dimensions of the fitting in the technical file. These
dimensions shall include the maximum height of the saddle, H, and for tapping tees the height of the
service pipe, H or H (see Figure 2).
1 2
NOTE For technical and design reasons, the minimum bore diameter D can be different from the one of
spigot fittings as given in 7.4.
8 © ISO 2019 – All rights reserved

Key
H height of the saddle, which comprises the distance from the top of the main pipe to the top of the tapping tee
or saddle
H height of service pipe, which comprises the distance from the axis of the main pipe to the axis of the service pipe
H height of service pipe, which comprises the distance from the top of the main pipe to the axis of the service pipe
L width of the tapping tee, which comprises the distance between the axis of the pipe and the plane of the mouth
of the service tee
Figure 2 — Dimensions of electrofusion saddle fittings
7.4 Dimensions of spigot end fittings
7.4.1 Diameter and length
When measured according to 7.1, the dimensions of spigot end fittings (see Figure 3) shall conform to
the values given in Table 3.
Key
D mean outside diameter of fusion end piece
D bore comprising minimum diameter of flow channel through body of fitting
E body wall thickness of fitting
E fusion face wall thickness
L cut-back length of fusion end piece
L tubular length of fusion end piece
a
D is measured in any plane parallel to the plane of the entrance face at a distance not greater than L (tubular
1 2
length) from the plane of the entrance face.
b
The measurement of this diameter does not include the fusion bead, if any.
c
It comprises the thickness measured at any point of the wall of the fitting.
d
It is measured at any point at a maximum distance of L (cut back length) from the entrance face and shall be
equal to the pipe wall thickness and tolerance to which it is intended to be butt fused, as specified in ISO 4427-
2:2019, Table 2. E for small dimensions is at least 3 mm.
e
It comprises the initial depth of the spigot end necessary for butt fusion or reweld and may be obtained by
joining a length of pipe to the spigot end of the fitting provided the wall thickness of the pipe is equal to E for
its entire length.
f
It comprises the initial length of the fusion end piece and shall allow the following (in any combination): the
use of clamps required in the case of butt fusion; assembly with an electrofusion fitting; assembly with a socket
fusion fitting; the use of a mechanical scraper.
Figure 3 — Dimensions of spigot fittings
10 © ISO 2019 – All rights reserved

Table 3 — Spigot dimensions
Dimensions in millimetres
c
Nominal Mean outside Min. Electrofusion Socket Butt fusion
b
outside diameter of bore fusion
a
diameter fusion end
Out- Cut- Tubular Tubular Out- Cut- Tubular
of spigot
d
of- back length length of- back length
round- length round- length
ness ness
d D D L L L L L
n 1 2 1 2 2 1 2
e f
min Max. min Max. min min min Max. min Normal Special
20 20,0 20,3 13 0,3 25 41 11 — — — —
25 25,0 25,3 18 0,4 25 41 12,5 — — — —
32 32,0 32,3 25 0,5 25 44 14,6 — — — —
40 40,0 40,4 31 0,6 25 49 17 — — — —
50 50,0 50,4 39 0,8 25 55 20 — — — —
63 63,0 63,4 49 0,9 25 63 24 1,5 5 16 5
75 75,0 75,5 59 1,2 25 70 25 1,6 6 19 6
90 90,0 90,6 71 1,4 28 79 28 1,8 6 22 6
110 110,0 110,7 87 1,7 32 82 32 2,2 8 28 8
125 125,0 125,8 99 1,9 35 87 35 2,5 8 32 8
140 140,0 140,9 111 2,1 38 92 — 2,8 8 35 8
160 160,0 161,0 127 2,4 42 98 — 3,2 8 40 8
180 180,0 181,1 143 2,7 46 105 — 3,6 8 45 8
200 200,0 201,2 159 3,0 50 112 — 4,0 8 50 8
225 225,0 226,4 179 3,4 55 120 — 4,5 10 55 10
250 250,0 251,5 199 3,8 60 129 — 5,0 10 60 10
280 280,0 281,7 223 4,2 75 139 — 9,8 10 70 10
315 315,0 316,9 251 4,8 75 150 — 11,1 10 80 10
355 355,0 357,2 283 5,4 75 164 — 12,5 10 90 12
400 400,0 402,4 319 6,0 75 179 — 14,0 10 95 12
450 450,0 452,7 359 6,8 100 195 — 15,6 15 60 15
500 500,0 503,0 399 7,5 100 212 — 17,5 20 60 15
560 560,0 563,4 447 8,4 100 235 — 19,6 20 60 15
630 630,0 633,8 503 9,5 100 255 — 22,1 20 60 20
710 710,0 714,9 567 10,6 125 280 — 24,8 20 60 20
800 800,0 805,0 639 12,0 125 300 — 28,0 20 60 20
a
Tolerance are in accordance with ISO 11922-1:2018 , grade B (see Reference [6] in the Bibliography).
b
The requirement on D are only applicable for SDR 11 or higher.
c
Spigot fittings designed for electrofusion are also suitable for butt fusion.
d
The values of L (electrofusion) are based on the following equations:
—  for d ≤ 90, L = 0,6d + 25 mm;
n 2 n
—  for d ≥ 110 to d ≤ 710, L = d /3 + 45 mm.
n n 2 n
e
Used by preference.
f
Used for fittings fabricated in the factory.
7.4.2 Wall thickness of the fusion end
The wall thickness of the fusion end, E , shall be at least equal to the minimum wall thickness of the
pipe, with a minimum value of 3 mm.
A thickness reduction, for example a chamfered edge, is permitted. between the plane of the entrance
face and a plane parallel to it, located at a distance not greater than (0,01 d + 1 mm).
e
The permissible tolerance of the wall thickness, E , at any point shall conform to the tolerance given in
ISO 4427-2:2019, Table 2 for the same wall thicknesses.
7.4.3 Wall thickness of the fitting body
The wall thickness, E, of the fitting body measured at any point, shall be at least equal to the nominal
wall thickness, e , of the pipe.
n
Any changes in wall thickness inside the body of the fitting shall be gradual in order to prevent stress
concentrations.
7.4.4 Other dimensions
The dimensional characteristics appropriate to each manufacturer, such as overall dimensions or
clamping requirements, shall be stated in a technical file.
7.5 Dimensions of socket fusion fittings
Where the description and dimensions of fittings of this type is required, Annex A applies.
7.6 Dimensions of fabricated fittings
Where the description and dimensions of fittings of this type is required, Annex B applies.
7.7 Design and dimensions of mechanical fittings
7.7.1 General
Mechanical fittings shall conform to ISO 17885.
Mechanical fittings shall allow installation with pipes according to ISO 4427-2.
If mechanical fittings are intended for jointing with spigot ends of fittings, spigot length (L ) and cut
back length (L ) should be considered (see Table 3).
The fittings shall be designed and manufactured in such a way that they can be used buried or above
ground. Pre-assembled mechanical fittings shall not be capable of being dismantled.
The fittings shall be designed to avoid twisting of the PE pipe during assembly.
The fittings shall not be assembled by thread cutting the PE pipe.
7.7.2 Mechanical fittings with polyethylene spigot ends
Polyethylene spigot ends shall conform to 7.4.
7.7.3 Mechanical fittings with polyethylene electrofusion sockets
Electrofusion sockets shall conform to 7.2.
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7.7.4 Threads
Threads on metal ends shall conform to ISO 7-1 or ISO 228-1, as applicable.
7.8 Dimensions of loose backing flanges and flange adapters
Dimensions of loose backing flanges and flange adapters shall be in accordance with ISO 9624.
8 Mechanical characteristics
8.1 General
Fittings shall be tested assembled with pipes conforming to ISO 4427-2 and/or fittings conforming to
this document.
Jointed pipe and fitting test pieces shall be assembled in accordance with the technical instructions
of the manufacturer, taking into account the manufacturing and assembly tolerances and the extreme
conditions of utilization described in ISO 4427-5.
8.2 Conditioning
Unless otherwise specified in the applicable test method, the test pieces shall be conditioned at
(23 ± 2) °C prior to testing.
8.3 Requirements
When tested in accordance with the test methods as specified in Table 4 using the indicated parameters,
the fittings shall have mechanical characteristics conforming to the requirements given in Table 4, as
applicable to the following types of fitting:
— (A) electrofusion socket fitting and socket fusion fitting;
— (B) electrofusion saddle fitting;
— (C) spigot end fitting.
For mechanical fittings, the requirements of ISO 17885 shall apply.
Table 4 — Mechanical characteristics
Test parameters
Characteristic Requirements Test method
Parameter Value
Hydrostatic No failure End caps Type A of ISO 1167-1:2006 ISO 1167-1:2006
strength during test and ISO 1167-4
Orientation Free
period of any
(20 °C, 100 h)
Conditioning time Shall conform to
test piece
ISO 1167-1:2006
a
Number of test pieces 3
b
Type of test Water-in-water
Circumferential PE 80 10,0 MPa
(hoop) stress in
PE 100 12,0 MPa
c
pipe for:
Test period 100 h
Test temperature 20 °C
Hydrostatic No failure End caps Type A of ISO 1167-1:2006 ISO 1167-1:2006
strength during test and ISO 1167-4
Orientation Free
period of any
(80 °C, 165 h)
d Conditioning time Shall conform to
test piece
ISO 1167-1:2006
a
Number of test pieces 3
b
Ty
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