FprEN 12666-1

SLOVENSKI STANDARD
01-junij-2025
Cevni sistemi iz polimernih materialov za odpadno vodo in kanalizacijo, ki delujejo
po težnostnem principu in so položeni v zemljo - Polietilen (PE) - 1. del:
Specifikacije za cevi, fitinge in sistem
Plastics piping systems for non-pressure underground drains and sewers - Polyethylene
(PE) - Part 1: Specifications for pipes, fittings and the system
Kunststoff-Rohrleitungssysteme für erdverlegte Abwasserkanäle und -leitungen -
Polyethylen (PE) - Teil 1: Anforderungen an Rohre, Formstücke und das
Rohrleitungssystem
Systèmes de canalisations en plastique pour les branchements et les collecteurs
d’assainissement enterrés sans pression - Polyéthylène (PE) - Partie 1 : Spécifications
pour les tubes, les raccords et le système
Ta slovenski standard je istoveten z: prEN 12666-1
ICS:
23.040.05 Cevovodi za zunanje Pipeline and its parts for
sisteme za odpadno vodo in external sewage systems
njihovi deli
91.140.80 Drenažni sistemi Drainage systems
93.030 Zunanji sistemi za odpadno External sewage systems
vodo
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

DRAFT
EUROPEAN STANDARD
prEN 12666-1
NORME EUROPÉENNE
EUROPÄISCHE NORM
April 2025
ICS 23.040.01; 23.040.05; 91.140.80; 93.030 Will supersede EN 12666-1:2005+A1:2011
English Version
Plastics piping systems for non-pressure underground
drains and sewers - Polyethylene (PE) - Part 1:
Specifications for pipes, fittings and the system
Systèmes de canalisations en plastique pour les Kunststoff-Rohrleitungssysteme für erdverlegte
branchements et les collecteurs d'assainissement Abwasserkanäle und -leitungen - Polyethylen (PE) -
enterrés sans pression - Polyéthylène (PE) - Partie 1 : Teil 1: Anforderungen an Rohre, Formstücke und das
Spécifications pour les tubes, les raccords et le système Rohrleitungssystem
This draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee
CEN/TC 155.
If this draft becomes a European Standard, CEN members are bound to comply with the CEN/CENELEC Internal Regulations
which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.

This draft European Standard was established by CEN in three official versions (English, French, German). A version in any other
language made by translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC
Management Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and
United Kingdom.
Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are
aware and to provide supporting documentation.

Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without
notice and shall not be referred to as a European Standard.

EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2025 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 12666-1:2025 E
worldwide for CEN national Members.

prEN 12666-1:2025 (E)
Contents Page
European foreword . 4
1 Scope . 5
2 Normative references . 6
3 Terms and definitions . 7
4 Symbols and abbreviations . 11
4.1 Symbols . 11
4.2 Abbreviations . 11
5 Material . 11
5.1 General. 11
5.2 Compound characteristics of pipe and injection moulded fittings . 12
5.3 Sealing ring retaining components . 12
5.4 Fused or welded joints . 13
6 Appearance and colour . 13
6.1 Appearance . 13
6.2 Colour . 13
7 Geometrical characteristics . 13
7.1 General. 13
7.2 Dimensions of pipes . 13
7.2.1 Outside diameter . 13
7.2.2 Lengths of pipe . 14
7.2.3 Wall thickness . 15
7.3 Dimensions of fittings . 16
7.3.1 Outside diameter . 16
7.3.2 Outside diameter for spigots with close tolerances (Type CT) . 16
7.3.3 Design lengths . 17
7.3.4 Wall thicknesses of the body of a fitting . 17
7.4 Dimensions of sockets and spigots . 18
7.4.1 Elastomeric ring seal sockets and spigots . 18
7.4.2 Butt fusion spigot ends . 21
7.4.3 Electrofusion sockets . 21
7.4.4 Flange joints . 22
7.5 Types of fittings . 23
8 Mechanical characteristics . 26
8.1 Mechanical characteristics of pipes . 26
8.2 Mechanical characteristics of fittings . 26
8.2.1 Ring stiffness class . 26
8.2.2 Additional requirements. 27
9 Physical characteristics . 27
9.1 Physical characteristics of pipes . 27
9.2 Physical characteristics of fittings . 28
10 Performance requirements . 29
11 Sealing rings . 30
prEN 12666-1:2025 (E)
12 Marking . 30
12.1 General . 30
12.2 Minimum required marking of pipes . 30
12.3 Minimum required marking of fittings . 31
12.4 Additional marking . 31
Annex A (normative) Compound PE material . 32
Annex B (normative) Utilization of PE recyclates . 34
B.1 General . 34
B.2 Agreed specification . 34
B.3 Additional specifications for recyclate and agreed specification . 35
Annex C (informative) General characteristics of PE pipes and fittings . 36
C.1 General . 36
C.2 Material characteristics . 36
C.3 Creep ratio . 36
C.4 Chemical resistance . 36
C.5 Abrasion resistance . 36
C.6 Hydraulic roughness . 37
C.7 Diametric deflection . 37
Annex D (informative) Product standards of components that can be connected to components
conforming to this document . 38
Bibliography . 39
prEN 12666-1:2025 (E)
European foreword
This document (prEN 12666-1:2025) has been prepared by Technical Committee CEN/TC 155 “Plastics
piping systems and ducting systems”, the secretariat of which is held by NEN.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document is currently submitted to CEN Enquiry.
This document will supersede EN 12666-1:2005+A1:2011.
This document includes new title, new template, significant technical changes to the material
clauses/annexes with respect to EN 12666-1:2005+A1:2011.
This document is a part of a System Standard for plastics piping systems of particular materials for a
specified application. There are a number of such System Standards.
System Standards are based on the results of the work being undertaken in ISO/TC 138 “Plastics pipes,
fittings and valves for the transport of fluids”, which is a Technical Committee of the International
Organization for Standardization (ISO).
System Standards are supported by separate standards on test methods to which references are made
throughout the System Standard.
System Standards are consistent with general standards on functional requirements and on
recommended practice for installation.
prEN 12666:2025 consists of the following parts under the general Plastics piping systems for non-
pressure underground drains and sewers — Polyethylene (PE)
— Part 1: Specifications for pipes, fittings and the system (this document);
— Part 2: Assessment of conformity (CEN/TS).
This part of EN 12666 includes Annex C (informative) “General characteristics of PE pipes and fittings”.
[11]
For guidance for installation, see CEN/TS 1046 . For guidance for installation, see
prCEN/TS 15223:2023.
prEN 12666-1:2025 (E)
1 Scope
This document specifies the definitions and requirements for solid-wall pipes with or without internal
skin and smooth internal and external surfaces extruded from the same compound throughout the wall,
fittings and the system of polyethylene (PE) piping systems to be intended for use in non-pressure
underground drains and sewers for foul wastewater.
NOTE 1 Products complying with this document can also be used in non-pressure underground drains and
sewers for surface water.
This document is applicable to:
a) non-pressure drains and sewers, which are intended to be used buried underground outside the
building structure; reflected in the marking of products by “U”;
b) non-pressure drains and sewers, which are intended to be used buried underground both outside
(application area code “U”) and within the building structure, reflected in the marking of products by
“UD”.
This document specifies test methods referred to in this document and test parameters.
This document is applicable to pipes and fittings with or without an integral socket.
This document covers a range of pipe and fitting sizes, stiffness classes, tolerance classes and gives
recommendations concerning colours.
NOTE 2 It is the responsibility of the purchaser or specifier to make the appropriate selections from these
aspects, taking into account their particular requirements and any relevant national regulations and installation
practices or codes.
[1]
In conjunction with CEN/TS 12666-2 it is applicable to PE pipes and fittings, their joints and to joints
with components of other plastics and non-plastics materials intended to be used for buried piping
systems for non-pressure drains an sewers.
The fittings can be manufactured by injection moulding or can be fabricated from pipes and/or
mouldings.
This document is applicable to PE pipes and fittings for the following types of joints:
— elastomeric ring seal joints;
— butt fused joints;
— electrofusion joints;
— mechanical joints.
NOTE 3 Pipes, fittings and other components conforming to any of the plastics product standards listed in the
Annex D (informative) can be used with pipes and fittings conforming to this document, provided they conform to
the requirements for joint dimensions given in Clause 7 and to the requirements of Clause 7 and Table 13.
prEN 12666-1:2025 (E)
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.
EN 681-1, Elastomeric seals — Materials requirements for pipe joint seals used in water and drainage
applications — Part 1: Vulcanized rubber
EN 681-2, Elastomeric Seals — Materials requirements for pipe joint seals used in water and drainage
applications — Part 2: Thermoplastic elastomers
EN 12099, Plastics piping systems — Polyethylene piping materials and components — Determination of
volatile content
EN 15346:2024, Plastics — Recycled plastics — Characterization of poly(vinylchloride) (PVC) recyclates
EN ISO 472:2013, Plastics — Vocabulary (ISO 472:2013)
EN ISO 527-2, Plastics — Determination of tensile properties — Part 2: Test conditions for moulding and
extrusion plastics (ISO 527-2)
EN ISO 580, Plastics piping and ducting systems — Injection-moulded thermoplastics fittings — Methods
for visually assessing the effects of heating (ISO 580)
EN ISO 1043-1, Plastics — Symbols and abbreviated terms — Part 1: Basic polymers and their special
characteristics (ISO 1043-1)
EN ISO 1133-1, Plastics — Determination of the melt mass-flow rate (MFR) and the melt volume-flow rate
(MVR) of thermoplastics — Part 1: Standard method (ISO 1133-1)
EN ISO 1167-1, Thermoplastics pipes, fittings and assemblies for the conveyance of fluids — Determination
of the resistance to internal pressure — Part 1: General method (ISO 1167-1)
EN ISO 1167-2, Thermoplastics pipes, fittings and assemblies for the conveyance of fluids — Determination
of the resistance to internal pressure — Part 2: Preparation of pipe test pieces (ISO 1167-2)
EN ISO 1183-1, Plastics — Methods for determining the density of non-cellular plastics — Part 1: lmmersion
method, liquid pycnometer method and titration method (ISO 1183-1)
EN ISO 1183-2, Plastics — Methods for determining the density of non-cellular plastics — Part 2: Density
gradient column method (ISO 1183-2)
EN ISO 2505, Thermoplastics pipes — Longitudinal reversion — Test method and parameters (ISO 2505)
EN ISO 3126, Plastics piping systems — Plastics components — Determination of dimensions (ISO 3126)
EN ISO 3451-1, Plastics — Determination of ash — Part 1: General methods (ISO 3451-1)
EN ISO 9969:2016, Thermoplastics pipes — Determination of ring stiffness (ISO 9969:2016)
EN ISO 11357-6, Plastics — Differential scanning calorimetry (DSC) — Part 6: Determination of oxidation
induction time (isothermal OIT) and oxidation induction temperature (dynamic OIT) (ISO 11357-6)
prEN 12666-1:2025 (E)
EN ISO 13254, Thermoplastics piping systems for non-pressure applications — Test method for
watertightness (ISO 13254)
EN ISO 13257, Thermoplastics piping systems for non-pressure applications — Test method for resistance
to elevated temperature cycling (ISO 13257)
EN ISO 13259, Thermoplastics piping systems for underground non-pressure applications — Test method
for leaktightness of elastomeric sealing ring type joints (ISO 13259:2020)
EN ISO 13263, Thermoplastics piping systems for non-pressure underground drainage and sewerage —
Thermoplastics fittings — Test method for impact strength (ISO 13263)
EN ISO 13264, Thermoplastics piping systems for non-pressure underground drainage and sewerage —
Thermoplastics fittings — Test method for mechanical strength or flexibility of fabricated fittings (ISO
13264)
3 Terms and definitions
For the purposes of this document, the terms and definitions given in EN ISO 472:2013 and EN ISO 1043-
1 and the following apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https://www.iso.org/obp/
— IEC Electropedia: available at https://www.electropedia.org/
3.1
drain
pipeline, usually underground, designed to carry wastewater from a source to a sewer
[SOURCE: EN 16323:2014, 2.2.3.1]
3.2
sewer
pipeline or other construction, usually underground, designed
[SOURCE: EN 16323:2014, 2.2.3.12]
3.3
foul wastewater
wastewater comprising domestic wastewater and/or industrial wastewater
[SOURCE: EN 16323:2014, 2.1.2.5]
3.4
surface water
water from precipitation, which has not seeped into the ground and is discharged to the drain or sewer
system directly from the ground or from exterior building surfaces
[SOURCE: EN 16323:2014, 2.1.1.3]
prEN 12666-1:2025 (E)
3.5
application area code
code used to mark pipes and fittings to indicate the permitted application area for which they are
intended:
U: code for the area more than 1 m from the building to which the buried piping system is connected
UD: code for the area U and within 1 m from the building where the pipes and fittings are buried
underground and are connected to the soil and waste discharge system of the building
Note 1 to entry: In the “UD” application area, the existence of hot water discharge in addition to external forces
from the surroundings is usual.
3.6
Geometrical definitions
3.6.1
nominal size
DN
numerical designation of the size of a component, which is a convenient round number approximately
equal to the manufacturing dimension, in millimetres
3.6.2
nominal size
DN/OD
nominal size, related to the outside diameter
3.6.3
nominal outside diameter
d
n
specified outside diameter, in millimetres, assigned to a nominal size DN/OD
3.6.4
outside diameter
d
e
value of the measurement of the outside diameter through its cross-section at any point of a pipe or spigot
end of a fitting, rounded up to the next greater 0,1 mm
3.6.5
mean outside diameter
dem
value of the measurement of the outer circumference of a pipe or spigot end of a fitting in any cross-
section, divided by π (≈ 3,142), rounded up to the next greater 0,1 mm
3.6.6
mean inside diameter of a socket
d
sm
arithmetical mean of a number of measurements of the inside diameter of a socket in the same cross-
section
prEN 12666-1:2025 (E)
3.6.7
wall thickness
e
value of the measurement of the wall thickness at any point around the circumference of a component
3.6.8
mean wall thickness
e
m
arithmetical mean of a number of measurements of the wall thickness, regularly spaced around the
circumference and in the same cross-section of a component, including the measured minimum and the
measured maximum values of the wall thickness in that cross-section
3.6.9
pipe series S
[2]
number for pipe designation (conforming to ISO 4065:2018 )
3.6.10
standard dimension ratio (SDR)
numerical designation of a pipe series, which is a convenient round number approximately equal to the
dimension ratio of the nominal outside diameter, d and the nominal wall thickness, e
n n
3.7
Mechanical definitions
3.7.1
nominal ring stiffness (SN)
numerical designation of the ring stiffness of a pipe or fitting, which is a convenient round number,
relative to the determined stiffness in kiloNewtons per square metre (kN/m ), indicating the minimum
ring stiffness of a pipe or fitting
3.8
Material definitions
3.8.1
virgin material
plastics material in the form of pellets, granules, powder, floc, etc. that has not been subjected to use or
processing other than that required for its initial manufacture
Note 1 to entry: Does not contain any reworked plastics material and/or plastics recyclate.
Note 2 to entry: Sometimes also referred to as “primary material” or “primary plastics feedstock”.
Note 3 to entry: It is understood that the addition of additives such as stabilizers and pigments is still resulting into
a virgin (plastics) material.
[SOURCE: ISO 472:2013, 2.1231, modified – Note 1 to entry, Note 2 to entry and Note 3 to entry added]
3.8.2
reworked material
plastics material from rejected unused products or trimmings capable of being reclaimed within the same
process that generated it
prEN 12666-1:2025 (E)
Note 1 to entry: Reworked material does not change the status of the feedstock.
Note 2 to entry: Previously referred to as “own reprocessed material”.
3.8.3
recyclate
plastics material resulting from the recycling of pre-consumer and post-consumer plastics products
Note 1 to entry: Also referred to as “secondary raw material” or “recycled plastics” or “regenerate”.
Note 2 to entry: Recycling can be chemical, physical or mechanical.
[SOURCE: ISO 472:2013, 2.1705, modified — Note 1 to entry and Note 2 to entry deleted, new Note 1 to
entry and Note 2 to entry introduced and ‘plastic waste’ changed into ‘pre-consumer and post-consumer
plastics products’]
3.8.4
pre-consumer material
plastics material diverted from the waste stream during a manufacturing process, excluding reworked
(plastics) material
Note 1 to entry: Previously referred to as “post-industrial material”.
Note 2 to entry: Different categories of pre-consumer material may be considered in the applicable product
standard.
[SOURCE: ISO 14021:2016, 7.8.1.1 modified – ‘plastics’ added, text deleted after ‘rework’ and 2 notes to
entry introduced]
3.8.5
post-consumer material
plastics material generated by households or by commercial, industrial and institutional facilities in their
role as end-users of the product which can no longer be used for its intended purpose
Note 1 to entry: This includes returns of material from the distribution chain.
Note 2 to entry: Different categories of post-consumer material may be considered in the applicable product
standard.
[SOURCE: ISO 14021:2016, 7.8.1.1 modified – ‘plastics’ added, last sentence changed into Note 1 to entry
and Note 2 to entry introduced]
3.8.6
compound
clearly defined homogenous mixture of substances used for the manufacture of the product
Note 1 to entry: In general, the term “compound” is used for polyolefins and the term “formulation” for PVC.
Note 2 to entry: For metals and when dealing with water and food contact regulations the term “composition” is
often used instead of compound/formulation.
3.8.7
agreed specification
specification of the relevant material characteristics agreed between the supplier of the recyclate and the
pipe and/or fitting manufacturer
prEN 12666-1:2025 (E)
Note 1 to entry: The agreed specification is often considered in the context of certification by a third party
organization.
4 Symbols and abbreviations
4.1 Symbols
For the purposes of this document, the following symbols apply.
d nominal diameter of the main of a branch
n,1
d nominal diameter of the branch of a branch
n,2
L insert length
Z Z Z design length of a fitting
1, 2, 3
Á nominal angle of fitting
4.2 Abbreviations
For the purposes of this document, the following abbreviations apply.
DN nominal size
DN/ID nominal size related to inside diameter
DN/OD nominal size related to outside diameter
PE polyethylene
S pipe series S
SDR standard dimension ratio
SN ring stiffness class
5 Material
5.1 General
The compound for production of pipes and fittings shall be PE-base material to which additives can be
added to enable conformity with the requirements of this document. (See also Annex A).
PE material may be virgin material, reworked material or recyclates (pre- or post-consumer).
Recyclates are permitted if they comply with Annex B.
The compound (including virgin material, reworked material, recyclates or a mixture, if applicable) shall
comply with the requirements given in 5.2.
The maximum amount of recyclate in the formulation is calculated based on the amount of separate
recyclate added to the compound plus the amount of recyclate present in reworked material which is
added to the compound.
Test results with the maximum specified amount of recyclates shall be taken as proving conformity of
products containing a lower amount of recyclates with the same agreed specification.
NOTE Attention is drawn to changing European and/or national regulations.
prEN 12666-1:2025 (E)
5.2 Compound characteristics of pipe and injection moulded fittings
When tested in accordance with the test method as specified in Table 1 using the indicated parameters,
the compound shall have characteristics conforming to the requirements given in Table 1.
Table 1 — Characteristics of PE compound for pipes and injection-moulded fittings
Characteristic Requirements Test parameters Test method
Resistance to No failure during End caps Type A or Type B EN ISO 1167-1
internal pressure the test period and
Test temperature 80 °C
b c
165 h
EN ISO 1167-2
Orientation Free
Number of test 3
pieces
Circumferential 4,0 Mpa
stress
Conditioning Shall conform to
period EN ISO 1167-1
Type of test Water-in-water
Test period 165 h
Resistance to No failure during End caps Type A or Type B EN ISO 1167-1
internal pressure the test period and
Test temperature 80 °C
b c
1 000 h
EN ISO 1167-2
Orientation Free
Number of test 3
pieces
Circumferential 2,8 Mpa
stress
Conditioning Shall conform to
period EN ISO 1167-1
Type of test Water-in-water
Test period 1 000 h
Melt mass-flow 0,2 ≤ MFR ≤ 1,4 Temperature 190 °C EN ISO 1133-1
a
rate g/10 min
Loading mass 5 kg
Thermal ≥ 20 min Temperature 200 °C EN ISO 11357-6
stability, OIT
Atmosphere Oxygen
a
This requirement only applies to pipes and fittings intended to be welded.
b
For the extrusion compound this test shall be carried out in the form of an injection-moulded or extruded sample
of a solid wall pipe made from the relevant compound.
c
For injection-moulding compound, this test shall be carried out in the form of an injection-moulded or extruded
sample in solid wall pipe form made from the relevant compound.

5.3 Sealing ring retaining components
It is permitted that sealing rings are retained using components made from any polymer.
prEN 12666-1:2025 (E)
5.4 Fused or welded joints
The design of fused or welded joints together with the manufacturer’s instructions for the jointing
process shall not cause the test assembly to fail the performance requirements given in Clause 10.
6 Appearance and colour
6.1 Appearance
When viewed without magnification, the following requirements apply:
— internal and external surfaces of pipes and fittings shall be smooth, clean and free from grooving,
blistering, impurities and pores and any other surface irregularity likely to prevent their
conformance with this document;
— pipe ends shall be cleanly cut and the ends of pipes and fittings shall be square to their axis.
Electrofusion fittings may feature exposed metallic components.
6.2 Colour
The pipes and fittings shall be coloured through the wall. The colour should preferably be black or as
agreed between manufacturer and purchaser.
A deviating colour for a co-extruded inner skin is permitted provided the material of this layer conforms
to Clause 5.
7 Geometrical characteristics
7.1 General
Dimensions shall be measured according to EN ISO 3126.
NOTE The figures are schematic sketches only, to indicate the relevant dimensions. They do not necessarily
represent manufactured components.
7.2 Dimensions of pipes
7.2.1 Outside diameter
The mean outside diameter, d , shall conform to Table 2.
em
prEN 12666-1:2025 (E)
Table 2 — Mean outside diameters
Dimensions in millimetres
Nominal size Nominal outside Mean outside diameter
diameter
DN/OD
d d d
n em,min em,max
110 110 110,0 111,0
125 125 125,0 126,2
160 160 160,0 161,5
200 200 200,0 201,8
250 250 250,0 252,3
315 315 315,0 317,9
355 355 355,0 358,2
400 400 400,0 403,6
450 450 450,0 454,1
500 500 500,0 504,5
560 560 560,0 565,0
630 630 630,0 635,7
710 710 710,0 716,4
800 800 800,0 807,2
1 000 1 000 1 000,0 1 009,0
1 200 1 200 1 200,0 1 210,0
1 400 1 400 1 400,0 1 410,0
1 600 1 600 1 600,0 1 610,0
7.2.2 Lengths of pipe
The effective length of a pipe, l, shall be not less than that declared by the manufacturer when measured
as shown in Figure 1.
prEN 12666-1:2025 (E)
Figure 1 — Effective length of pipes for single-socketed pipes with ring seal and plain-ended
pipes, both with and without chamfer

7.2.3 Wall thickness
The wall thickness, e, shall conform to Table 3, where a maximum wall thickness at any point of 1,25e
min
is permitted provided that the mean wall thickness, e , is less than or equal to the specified e . The e
m m,max m
value needs not to be determined if the e value is less than or equal to e in Table 3.
max m,max
prEN 12666-1:2025 (E)
Table 3 — Wall thicknesses
Dimensions in millimetres
a
Nominal Nominal Wall thickness
b
size outside SN 2 SN 4 SN 8 SN 16
DN/OD diameter S 16 S 12,5 S 10 S 8
SDR 33 SDR 26 SDR 21 SDR 17
c c c c
d e e e e e e e e
n min m,max min m,max min m,max min m,max
d d
110 110 – – 4,2 4,9 5,3 6,1 6,6 7,5
d d
125 125 – – 4,8 5,5 6,0 6,9 7,4 8,4
d d
160 160 – – 6,2 7,1 7,7 8,7 9,5 10,7
d d
200 200 – – 7,7 8,7 9,6 10,8 11,9 13,3

250 250 7,7 8,7 9,6 10,8 11,9 13,3 14,8 16,5
315 315 9,7 10,9 12,1 13,6 15,0 16,8 18,7 21,7
355 355 10,9 12,2 13,6 15,2 16,9 19,7 21,1 24,5
400 400 12,3 13,8 15,3 17,1 19,1 22,2 23,7 27,5

450 450 13,8 15,4 17,2 20,0 21,5 24,8 26,7 30,9
500 500 15,3 17,1 19,1 22,2 23,9 27,4 29,7 34,4
560 560 17,2 20,0 21,4 24,9 26,7 30,9 33,2 38,4
630 630 19,3 22,5 24,1 28,0 30,0 34,7 37,4 43,3
710 710 21,8 25,3 27,2 31,5 33,9 39,2 42,1 48,7
800 800 24,5 28,4 30,6 35,4 38,1 44,1 47,4 54,8

1 000 1 000 30,6 35,4 38,2 44,2 47,7 55,1 - -
1 200 1 200 36,7 42,4 45,9 53,0 57,2 66,0 - -
1 400 1 400 42,9 49,6 53,5 61,8 – – - -
1 600 1 600 49,0 56,6 61,2 70,6 – – - -
a
[13]
The tolerances for wall thicknesses conform to ISO 11922-1 grade W for wall thickness equal to or less than
16 mm and grade X for wall thickness larger than 16 mm.
b
SN 2 is applicable for application area “UD” only.
c
[2]
The emin-values are in conformance with ISO 4065:2018 .
d
[19]
For sizes DN 110 to 200 in SN 2 reference is made to EN 1519-1:2019, Table 3 and Table 4 , pipe series S16.
Such pipes may be used outside the application area B when encased in concrete or laid in ducts.

7.3 Dimensions of fittings
7.3.1 Outside diameter
The mean outside diameter, d , of the spigot shall conform to Table 2.
em
7.3.2 Outside diameter for spigots with close tolerances (Type CT)
For the purposes of this document in addition to the dimensions and tolerances given in Table 2 for spigot
ends of fittings, tolerances that are in accordance with EN 1401-1 may be used.
If these tolerances, classified as close tolerances (CT), are required the mean outside diameter, dem, of the
spigot and the tolerances shall conform to Table 4.
prEN 12666-1:2025 (E)
Table 4 — Mean outside diameters for spigots with close tolerances type CT
Dimensions in millimetres
Nominal size Nominal outside Mean outside diameter
diameter
DN/OD d d d
n em,min em,max
110 110 110,0 110,3
125 125 125,0 125,3
160 160 160,0 160,4
200 200 200,0 200,5
250 250 250,0 250,5
315 315 315,0 315,6
355 355 355,0 355,7
400 400 400,0 400,7
450 450 450,0 450,8
500 500 500,0 500,9
630 630 630,0 631,1
Spigot ends of fittings with mean outside diameters conforming to Table 4 may be used with pipes and
fittings conforming to EN 1401-1 provided that the socket(s) for these pipes and fittings are intended to
be used with elastomeric ring seal joints.
NOTE Spigots ends of fittings with mean outside diameters conforming to Table 4 are normally injection-
moulded or machined.
7.3.3 Design lengths
The design lengths, Z , shall be declared by the manufacturer.
d
The design lengths (see the dimensions Z in Figures 8 to 12 and Figures 15 to 20) are intended to assist
d
[3]
in the design of moulds and are not intended to be used for quality control purposes. ISO 265-1:1988
may be used as a guideline.
7.3.4 Wall thicknesses of the body of a fitting
7.3.4.1 The minimum wall thickness, e , of the body or the spigot of a fitting shall conform to
min
Table 3, except that a reduction of 5 % resulting from core shift is permitted. In such a case, the mean of
two opposite wall thicknesses shall be equal to or exceed the values given in this table.
7.3.4.2 Where a fitting or adaptor provides for a transition between two nominal sizes, the wall
thickness of each connecting part shall conform to the requirements for the applicable nominal size. In
such a case the wall thickness of the fitting body is permitted to change gradually from one wall thickness
to the other.
7.3.4.3 The wall thickness of fabricated fittings, except for spigot and socket, may be changed locally
as
by the fabrication process, provided that the minimum wall thickness of the body conforms to e3,min
given in Table 6 for the size and pipe series concerned.
prEN 12666-1:2025 (E)
7.4 Dimensions of sockets and spigots
7.4.1 Elastomeric ring seal sockets and spigots
7.4.1.1 Diameters and lengths
The diameters and lengths of elastomeric ring seal sockets and lengths of spigots shall conform to Table 5
(see Figures 2, 3, 4 or 5, as applicable).
Where sealing rings are firmly retained, the dimensions for the minimum value for A and the maximum
value for C shall be measured to the effective sealing point (see Figure 4) as specified by the manufacturer.
This point shall give a full sealing action.
Different designs of elastomeric ring seal sockets are permitted, provided they conform to the
requirements given in Table 12.
Table 5 — Socket diameters and lengths of sockets and spigots
Dimensions in millimetres
Nominal Nominal Socket Spigot
size DN/OD outside
diameter
a
d d A C L
n sm,min min max 1,min
110 110 111,1 40 40 62
125 125 126,3 43 43 68
160 160 161,6 50 50 82
200 200 201,9 58 58 98
250 250 252,4 68 68 118
315 315 318,0 81 81 144
355 355 358,3 89 89 160
400 400 403,7 98 98 178
450 450 454,2 108 108 198
500 500 504,6 118 118 218
560 560 565,1 130 130 242
630 630 635,8 144 144 270
a
The socket is designed for an effective length of pipe of 6 m.

For sockets and spigots that have a nominal outside diameter greater than 630 mm, the values of d ,
sm,min
A , C and L shall be calculated using the following equations:
min max 1,min
A = (0,2d + 18) mm;
min n
C = (0,2d + 18) mm;
max n
d = 1,0092d mm;
sm,min n
L = (0,4d + 18) mm.
1,min n
For pipe lengths longer than 6 m the length of engagement, A, in the socket shall be calculated from the
formula: A = (0,2d + 3 × l) mm, where l is the pipe length, in metres.
n
prEN 12666-1:2025 (E)
Ring seal socket
with chamfer
Ring seal socket
without chamfer
Figure 2 — Dimensions of sockets for elastomeric ring seal joints

Figure 3 — Typical groove designs for elastomeric ring seal sockets
prEN 12666-1:2025 (E)
Figure 4 — Example for measuring the effective sealing point

Figure 5 — Spigot lengths
7.4.1.2 Wall thicknesses of sockets
The wall thicknesses of sockets, e and e (see Figure 2), except the socket mouth, shall conform to
2 3
Table 6.
A reduction of 5 % of e and e resulting from core shift is permitted. In such a case the mean of two
2 3
opposite wall thicknesses shall be equal to or exceed the applicable values given in Table 6.
prEN 12666-1:2025 (E)
Table 6 — Wall thicknesses of sockets
Dimensions in millimetres
Nominal Nominal Wall thickness
size outside
a
SN 2 SN 4 SN 8 SN 16
DN/OD diameter
S 16 S 12,5 S 10 S 8
SDR 33 SDR 26 SDR 21 SDR 17
d e e e e e e e
n e2,min 3,min 2,min 3,min 2,min 3,min 2,min 3,min
110 110 - - 3,8 3,2 4,8 4,0 6,0 5,0
125 125 - - 4,4 3,6 5,4 4,5 6,7 5,6
160 160 - - 5,6 4,7 7,0 5,8 8,6 7,2
200 200 - - 7,0 5,8 8,7 7,2 10,8 9,0

250 250 7,0 5,8 8,7 7,2 10,8 9,0 13,4 11,1
315 315 8,8 7,3 10,9 9,1 13,5 11,3 16,9 14,1
355 355 9,9 8,2 12,3 10,2 15,3 12,7 17,8 18,4
≥ 400 ≥ 400 11,1 9,3 13,8 11,5 17,2 14,4 21,4 17,8
a
SN 2 is applicable for application area “UD” only.

Where a sealing ring is located by means of a retaining cap or ring (see Figure 6) the wall thickness in this
area shall be calculated by the addition of the wall thickness of the socket and the wall thickness of the
retaining ring or cap at corresponding places in the same cross section.

Figure 6 — Example for calculation of the wall thickness of sockets with retaining cap
7.4.2 Butt fusion spigot ends
The mean outside diameters, d , and wall thicknesses, e, of spigots intended for butt fusion shall conform
em
to the diameters and corresponding pipe size and series as given in Tables 2 and 3 respectively.
7.4.3 Electrofusion sockets
The dimensions of electrofusion sockets shall conform to the values given in Table 7 (see Figure 7).
prEN 12666-1:2025 (E)
Figure 7 — Electrofusion socket
Table 7 — Dimensions of electrofusion sockets
Dimensions in millimetres
Nominal Nominal Mean Minimum Minimum Minimum Wall
size outside inside depth of length of unheated thickness
DN/OD diamete diamete penetratio fusion zone entra
...