EN 10253-1:2026

SLOVENSKI STANDARD
01-oktober-2026
Cevni fitingi za soležne zvare - 1. del: Ogljikovo jeklo za splošno uporabo in brez
posebnih zahtev kontrole
Butt-welding pipe fittings - Part 1: Wrought carbon steel for general use and without
specific inspection requirements
Formstücke zum Einschweißen - Teil 1: Unlegierter Stahl für allgemeine Anwendungen
und ohne besondere Prüfanforderungen
Raccords à souder bout à bout - Partie 1: Acier au carbone pour usages généraux et
sans contrôle spécifique
Ta slovenski standard je istoveten z: EN 10253-1:2026
ICS:
23.040.40 Kovinski fitingi Metal fittings
77.140.45 Nelegirana jekla Non-alloyed steels
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN 10253-1
EUROPEAN STANDARD
NORME EUROPÉENNE
August 2026
EUROPÄISCHE NORM
ICS 77.140.45 Supersedes EN 10253-1:1999
English Version
Butt-welding pipe fittings - Part 1: Wrought carbon steel
for general use and without specific inspection
requirements
Raccords à souder bout à bout - Partie 1: Acier au Formstücke zum Einschweißen - Teil 1: Unlegierter
carbone pour usages généraux et sans contrôle Stahl für allgemeine Anwendungen und ohne
spécifique besondere Prüfanforderungen
This European Standard was approved by CEN on 15 June 2026.

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. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
member.
This European Standard exists 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.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2026 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 10253-1:2026 E
worldwide for CEN national Members.

Contents Page
European foreword . 4
Introduction . 6
1 Scope . 7
2 Normative references . 7
3 Terms and definitions . 8
4 Symbols and abbreviations . 8
5 Classification and designation . 10
5.1 Classification of grades . 10
5.2 Designation of steel grades . 10
5.3 Designation of fittings . 10
5.3.1 General . 10
5.3.2 Elbows and return bends . 10
5.3.3 Reducers . 10
5.3.4 Tees . 10
5.3.5 Caps . 10
6 Information to be supplied . 11
6.1 Mandatory information . 11
6.2 Options . 11
6.3 Examples of an order . 11
6.3.1 Example 1 . 11
6.3.2 Example 2 . 11
6.3.3 Example 3 . 11
7 Resistance to internal pressure . 12
8 Manufacturing process . 12
8.1 Steelmaking process . 12
8.2 Product making process for fittings and heat treatment . 12
8.2.1 Product making process . 12
8.2.2 Welding . 13
8.2.3 Heat treatment condition . 13
9 Technical requirements. 13
9.1 General . 13
9.2 Chemical composition . 14
9.3 Mechanical properties . 14
9.4 Weldability . 14
10 Appearance (delivery conditions) . 14
10.1 Definitions of surface imperfections . 14
10.2 Appearance . 15
11 Dimensions and tolerances . 16
11.1 Dimensions . 16
11.1.1 General . 16
11.1.2 Elbows . 16
11.1.3 Tees . 17
11.1.4 Reducers . 18
11.1.5 Caps . 19
11.1.6 Diameters and wall thicknesses . 20
11.2 Dimensional tolerances . 20
11.2.1 Diameter . 20
11.2.2 Out of roundness . 21
11.2.3 Wall thickness tolerances . 21
11.2.4 Tolerances on specific dimensions and form . 21
11.3 Performance of the end bevelling . 22
12 Inspection . 23
12.1 Type of inspection . 23
12.2 Inspection documents . 23
12.2.1 Type of inspection documents . 23
12.2.2 Content of inspection documents . 23
12.3 Summary of inspection and testing . 24
13 Sampling . 24
13.1 Frequency of tests. 24
13.2 Preparation of samples and test pieces for mechanical tests. 24
14 Test methods . 25
14.1 Chemical analysis . 25
14.2 Tensile test on the base material at room temperature . 25
14.3 Hardness test . 25
14.4 Dimensional testing . 25
14.5 Visual testing (VT) . 25
14.6 Non-destructive testing (NDT) . 26
14.6.1 Personnel . 26
14.6.2 NDT of the weld . 26
15 Marking . 26
16 Protection and packaging . 27
Annex A (normative) Dimensions . 28
Bibliography . 33
European foreword
This document (EN 10253-1:2026) has been prepared by Technical Committee CEN/TC 459 “ECISS –
European Committee for Iron and Steel Standardization” , the secretariat of which is held by AFNOR.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by February 2027, and conflicting national standards shall
be withdrawn at the latest by February 2027.
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 supersedes EN 10253-1:1999.
a) restructuring of Clauses to reflect new layout of EN 10253-2 and EN 10253-4;
b) revision of introduction;
c) revision of scope;
d) update of normative references;
e) update of terms, symbols and abbreviations;
f) removal of dished ends;
g) moved steel grade S265 from Annex A to Clause 9;
h) update of options;
i) revision of technical requirements and dimensions to reflect current state of the art;
j) revision of Figures;
k) moved dimensions to Annex A;
l) standard editorially revised.
EN 10253 comprises a series of European Standards about Butt-welding pipe fittings, namely:
— Part 1: Wrought carbon steel for general use and without specific inspection requirements;
— Part 2: Non alloy and ferritic alloy steels with specific inspection requirements;
— Part 3: Wrought austenitic and austenitic-ferritic (duplex) stainless steels without specific inspection
requirements;
Through its sub-committee SC 10 “Steel tubes, and iron and steel fittings” (secretariat: UNI).
— Part 4: Wrought austenitic and austenitic-ferritic (duplex) stainless steels with specific inspection
requirements.
Any feedback and questions on this document should be directed to the users’ national standards body.
A complete listing of these bodies can be found on the CEN website.
According to the CEN-CENELEC Internal Regulations, the national standards organisations of the
following countries are bound to implement this European Standard: 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 the United
Kingdom.
Introduction
In writing this document the competent committee recognized that there are two broad types of products
commonly used, and decided to reflect these in the standard by differentiating between two parts.
EN 10253-1 describes fittings without formal reference to the pressure resistance, which are not
intended to be used in applications, covered by the European Legislation for Pressure Equipment.
EN 10253-2 defines fittings that are intended to be used in applications covered by the European
Legislation for Pressure Equipment.
The selection of steel type and requirement level depend on many factors; the properties of the fluid to
be conveyed, the service conditions, the design code and any statutory requirements should all be taken
into consideration. Therefore this document gives no detailed guidelines for the application of different
parts. It is the ultimate responsibility of the user to select the appropriate part for the intended
application.
1 Scope
This document specifies the technical delivery requirements for seamless and welded butt-welding
fittings (elbows, concentric and eccentric reducers, equal and reducing tees, caps) made of wrought
carbon steel without specific inspection requirements.
It specifies:
a) steel grade and its chemical compositions;
b) mechanical properties;
c) dimensions and tolerances;
d) requirements for inspection and testing;
e) inspection documents;
f) marking;
g) protection and packaging.
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 10020, Definition and classification of grades of steel
EN 10021, General technical delivery conditions for steel products
EN 10079, Definition of steel products
EN 10168, Steel products — Inspection documents — List of information and description
EN 10204, Metallic products — Types of inspection documents
EN 10266, Steel tubes, fittings and structural hollow sections — Symbols and definitions of terms for use in
product standards
EN ISO 377, Steel and steel products — Location and preparation of samples and test pieces for mechanical
testing (ISO 377)
EN ISO 2566-1, Steel — Conversion of elongation values —Part 1: Carbon and low alloy steels (ISO 2566-1)
EN ISO 3166-1, Codes for the representation of names of countries and their subdivisions — Part 1: Country
code (ISO 3166-1)
EN ISO 4885, Ferrous materials — Heat treatments — Vocabulary (ISO 4885)
EN ISO 5817, Welding — Fusion-welded joints in steel, nickel, titanium and their alloys (beam welding
excluded) — Quality levels for imperfections (ISO 5817)
EN ISO 6506-1, Metallic materials — Brinell hardness test — Part 1: Test method (ISO 6506-1)
EN ISO 6892-1, Metallic materials — Tensile testing — Part 1: Method of test at room temperature
(ISO 6892-1)
EN ISO 9606-1, Qualification testing of welders — Fusion welding — Part 1: Steels (ISO 9606-1)
EN ISO 9712, Non-destructive testing — Qualification and certification of NDT personnel (ISO 9712)
EN ISO 10893-10, Non-destructive testing of steel tubes — Part 10: Automated full peripheral ultrasonic
testing of seamless and welded (except submerged arc-welded) steel tubes for the detection of longitudinal
and/or transverse imperfections (ISO 10893-10)
EN ISO 10893-11, Non-destructive testing of steel tubes — Part 11: Automated ultrasonic testing of the weld
seam of welded steel tubes for the detection of longitudinal and/or transverse imperfections (ISO 10893-11)
EN ISO 15607, Specification and qualification of welding procedures for metallic materials — General rules
(ISO 15607)
3 Terms and definitions
For the purposes of this document, the terms and definitions given in EN 10020, EN 10021, EN 10079,
EN ISO 377, and EN ISO 4885 and the following 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 https://www.electropedia.org/
3.1
model
designation for elbows, return bends, and reducers
Note 1 to entry: For elbows and return bends the model defines the bending diameter of the piece.
Note 2 to entry: For reducers the model defines concentric, eccentric, or concentric - form 1 shape of the piece.
3.2
weld during manufacture
weld made for obtaining a fitting
Note 1 to entry: This term does not include the tube welds when a tube is used as starting material.
3.3
seamless fitting
fitting manufactured without welding from starting material which is not welded
3.4
welded fitting
fitting made from welded starting material or fitting where welding is a part of the manufacturing process
4 Symbols and abbreviations
For the purposes of this document, the symbols defined in EN 10266 and the following apply:
A
Percentage of elongation at rupture, with reference to gauge length of 5,65 S
o
B Back to face distance for return bends, expressed in millimetres
C Centre to centre distance for return bends (C = 2R), expressed in millimetres
Specified outside diameter for elbows, return bends, equal tees, caps and the major outside
D
diameter for reducers and reducing tees, expressed in millimetres
D
Specified minor outside diameter for reducers and reducing tees, expressed in millimetres
D
Maximum diameter in one section, expressed in millimetres
max
D
Minimum diameter in the same section, expressed in millimetres
min
Distance from the axis of the branch outlet to the face of the centre body of tees, expressed
F
in millimetres
Distance from the axis of the centre line to the face of the branch outlet expressed in
G
millimetres
Inside diameter at the welding ends of elbows, return bends, equal tees and at the major
ID
welding end of reducers and reducing tees (ID = D − 2T), expressed in millimetres
Inside diameter at the minor welding end of reducers and reducing tees (ID = D − 2T ),
1 1 1
ID
expressed in millimetres
K Total height for caps, expressed in millimetres
L Face to face distance for reducers, expressed in millimetres
O Out of roundness, expressed in %
v
R Bending radius of elbows and return bends, expressed in millimetres
R
Inside spherical radius of cap, expressed in millimetres
R
Inside knuckle radius of cap, expressed in millimetres
R
Upper yield strength, expressed in megapascals
eH
R
Tensile strength, expressed in megapascals
m
R
Minimum 0,2 % proof strength, plastic extension expressed in megapascals
p0,2
Specified wall thickness at the welding ends for elbows, return bends, equal tees and caps
T
or on the D end for reducers and reducing tees, expressed in millimetres
Specified wall thickness on the D welding end of reducers and reducing tees, expressed in
T
millimetres
Distance from the extrados to the centre of a 90° elbow at the welding ends, expressed in
W
millimetres
X Tolerance on the form of fittings
Distance from the extrados to the centre of a 45° elbow at the welding ends, expressed in
Z
millimetres
5 Classification and designation
5.1 Classification of grades
In accordance with the classification system in EN 10020, the steel grades in this document are classified
as non-alloy quality steels.
5.2 Designation of steel grades
For the fittings covered by this document the steel designation consists of:
— the number of this document (EN 10253-1);
plus
— steel grade S235 or S265.
5.3 Designation of fittings
5.3.1 General
Fittings are designated by their name and the following parameters.
5.3.2 Elbows and return bends
Elbows and return bends are designated by the following parameters:
a) model (2D, 3D or 5D);
b) angle;
c) outside diameter (D);
d) wall thickness (T).
5.3.3 Reducers
Reducers are designated by the following parameters:
a) model [concentric (con), eccentric (ecc), or concentric - form 1 (con-1)];
b) major diameter (D) and wall thickness (T);
c) minor diameter (D ) and wall thickness (T ).
1 1
5.3.4 Tees
Equal and reducing tees are designated by the following parameters:
a) major diameter (D) and minor diameter (D );
b) wall thickness (T) and wall thickness (T ).
NOTE If only one pair of dimension (D x T) is given, an equal tee is meant.
5.3.5 Caps
Caps are designated by the following parameters:
a) outside diameter (D);
b) wall thickness (T).
6 Information to be supplied
6.1 Mandatory information
The following information shall be supplied at the time of enquiry and order:
a) quantity required (number of pieces);
b) reference to this document;
c) designation of fittings (see 5.3);
d) designation of the steel grade (see 5.2);
e) options, if any (see 6.2).
6.2 Options
A number of options are specified in this document and these are listed below. In the event that no option
has been specified at the time of enquiry and order, the fittings shall be supplied in accordance with the
basic specification (see 6.1).
1) Starting product form (see 8.2.1)
NOTE Use for ordering seamless (S) or welded (W) fittings.;
2) Method of marking (see Clause 15);
3) Special packaging, coating or end plugs (see Clause 16).
6.3 Examples of an order
6.3.1 Example 1
1 000 elbows in accordance with this document of model 3D with angle 90° having an outside diameter
of 60,3 mm and a wall thickness of 2,9 mm made of steel grade S235.
1 000 elbows — EN 10253-1 — model 3D — 90° — 60,3 × 2,9 — S235
6.3.2 Example 2
50 elbows in accordance with this document of model 3D with angle 90° having an outside diameter of
273,0 mm and a wall thickness of 9,5 mm made of steel grade S265.
50 elbows — EN 10253-1 — model 3D — 90° — 273,0 × 9,5 — S265
6.3.3 Example 3
2 000 concentric reducers (con) in accordance with this document, having an outside diameter 219,1 mm
and a wall thickness of 6,3 mm and a reduced outside diameter 139,7 mm and a wall thickness of 4,0 mm,
made of steel grade S235.
2 000 reducers con — EN 10253-1 — 219,1 × 6,3 — 139,7 × 4,0 — S235
...