SIST EN ISO 3821:2020

SLOVENSKI STANDARD
SIST EN ISO 3821:2020
01-marec-2020
Nadomešča:
SIST EN ISO 3821:2011
Oprema za plamensko varjenje - Gumene cevi za varjenje, rezanje in sorodne
postopke (ISO 3821:2019)
Gas welding equipment - Rubber hoses for welding, cutting and allied processes (ISO
3821:2019)
Gasschweißgeräte - Gummischläuche für Schweißen, Schneiden und verwandte
Prozesse (ISO 3821:2019)
Matériel de soudage aux gaz - Tuyaux souples en caoutchouc pour le soudage, le
coupage et les techniques connexes (ISO 3821:2019)
Ta slovenski standard je istoveten z: EN ISO 3821:2019
ICS:
25.160.30 Varilna oprema Welding equipment
83.140.40 Gumene cevi Hoses
SIST EN ISO 3821:2020 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------
SIST EN ISO 3821:2020

---------------------- Page: 2 ----------------------
SIST EN ISO 3821:2020


EN ISO 3821
EUROPEAN STANDARD

NORME EUROPÉENNE

September 2019
EUROPÄISCHE NORM
ICS 25.160.30; 83.140.40 Supersedes EN ISO 3821:2010
English Version

Gas welding equipment - Rubber hoses for welding, cutting
and allied processes (ISO 3821:2019)
Matériel de soudage aux gaz - Tuyaux souples en Gasschweißgeräte - Gummischläuche für Schweißen,
caoutchouc pour le soudage, le coupage et les Schneiden und verwandte Prozesse (ISO 3821:2019)
techniques connexes (ISO 3821:2019)
This European Standard was approved by CEN on 26 May 2019.

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, Turkey 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
© 2019 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 3821:2019 E
worldwide for CEN national Members.

---------------------- Page: 3 ----------------------
SIST EN ISO 3821:2020
EN ISO 3821:2019 (E)
Contents Page
European foreword . 3

2

---------------------- Page: 4 ----------------------
SIST EN ISO 3821:2020
EN ISO 3821:2019 (E)
European foreword
This document (EN ISO 3821:2019) has been prepared by Technical Committee ISO/TC 44 "Welding
and allied processes" in collaboration with Technical Committee CEN/TC 121 “Welding and allied
processes” the secretariat of which is held by DIN.
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 March 2020, and conflicting national standards shall
be withdrawn at the latest by March 2020.
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 ISO 3821:2010.
According to the CEN-CENELEC Internal Regulations, the national standards organizations 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, Turkey and the
United Kingdom.
Endorsement notice
The text of ISO 3821:2019 has been approved by CEN as EN ISO 3821:2019 without any modification.

3

---------------------- Page: 5 ----------------------
SIST EN ISO 3821:2020

---------------------- Page: 6 ----------------------
SIST EN ISO 3821:2020
INTERNATIONAL ISO
STANDARD 3821
Fifth edition
2019-08
Gas welding equipment — Rubber
hoses for welding, cutting and allied
processes
Matériel de soudage aux gaz — Tuyaux souples en caoutchouc pour le
soudage, le coupage et les techniques connexes
Reference number
ISO 3821:2018(E)
©
ISO 2018

---------------------- Page: 7 ----------------------
SIST EN ISO 3821:2020
ISO 3821:2018(E)

COPYRIGHT PROTECTED DOCUMENT
© ISO 2018
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: +41 22 749 01 11
Fax: +41 22 749 09 47
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2018 – All rights reserved

---------------------- Page: 8 ----------------------
SIST EN ISO 3821:2020
ISO 3821:2018(E)

Contents Page
Foreword .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Abbreviated terms . 2
5 Application . 2
6 Hose designation . 2
7 Materials . 3
7.1 Construction . 3
7.1.1 Light and normal duty hoses . 3
7.1.2 Flux fuel gas hose . 3
7.1.3 Twin hose . 3
7.2 Manufacture . 3
8 Dimensions and tolerances . 3
8.1 Inside diameters . 3
8.2 Outside diameters . 4
8.3 Wall thickness . 4
8.4 Concentricity (total indicator reading) . 5
8.5 Cut lengths and tolerances . 5
8.6 Disclosure of inside diameter and outside diameter . 5
9 Requirements and type tests . 5
9.1 General . 5
9.2 Basic requirements . 5
9.2.1 Tensile strength and elongation at break . 5
9.2.2 Accelerated ageing . 5
9.2.3 Adhesion . 5
9.2.4 Hydrostatic requirements . 6
9.2.5 Flexibility at ambient temperature . 6
9.2.6 Low-temperature flexibility . 6
9.2.7 Protection against incandescent particles and hot surfaces . 6
9.2.8 Ozone resistance . 6
9.3 Special requirements . 6
9.3.1 Non-ignition requirement for oxygen hoses . 6
9.3.2 Resistance to acetone and dimethylformamide for acetylene hoses . 7
9.3.3 Resistance to n-pentane for propane hoses . 7
9.3.4 Resistance to azeotrope of trimethylborate with methanol for flux fuel gas
hoses . 7
9.3.5 Flexibility of flux fuel gas hoses . 8
9.3.6 Permeability to LPG, MPS, and natural gas of methane hoses, universal
fuel gas hoses, and flux fuel gas hoses . 8
9.3.7 Requirements for twin hoses . 8
9.3.8 Requirements for universal fuel gas hose . 8
10 Hose colour and gas identification . 8
10.1 General . 8
10.2 Gas identification . 8
10.3 Marking . 9
Annex A (normative) Method of test for non-ignition .10
Annex B (normative) Method of test for resistance to n-pentane .12
Annex C (normative) Method of test for resistance to incandescent particles and hot surfaces .13
© ISO 2018 – All rights reserved iii

---------------------- Page: 9 ----------------------
SIST EN ISO 3821:2020
ISO 3821:2018(E)

Annex D (normative) Summary of requirements and type tests .15
Annex E (normative) Alternative oxygen gas colour codes .16
Bibliography .17
iv © ISO 2018 – All rights reserved

---------------------- Page: 10 ----------------------
SIST EN ISO 3821:2020
ISO 3821:2018(E)

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 44, Welding and allied processes,
Subcommittee SC 8, Equipment for gas welding, cutting and allied processes.
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.
Official interpretations of TC 44 documents, where they exist, are available from this page: https:
//committee .iso .org/sites/tc44/home/interpretation .html.
This fifth edition cancels and replaces the fourth edition (ISO 3821:2008) which has been technically
revised.
The main changes compared to the previous edition are as follows:
— the definition of maximum working pressure has been added;
— Clauses 7 to 9 have been revised;
— the requirements for marking have been revised;
— editorial changes have been made.
© ISO 2018 – All rights reserved v

---------------------- Page: 11 ----------------------
SIST EN ISO 3821:2020

---------------------- Page: 12 ----------------------
SIST EN ISO 3821:2020
INTERNATIONAL STANDARD ISO 3821:2018(E)
Gas welding equipment — Rubber hoses for welding,
cutting and allied processes
1 Scope
This document specifies requirements for rubber hoses (including twin hoses) for welding, cutting and
allied processes.
This document specifies requirements for rubber hoses for normal duty of 2 MPa (20 bar) and light duty
[limited to hoses for maximum working pressure of 1 MPa (10 bar) and with bore up to and including
6,3 mm].
This document applies to hoses operated at temperatures −20 °C to +60 °C and used in:
— gas welding and cutting;
— arc welding under the protection of an inert or active gas;
— processes allied to welding and cutting, in particular, heating, brazing, and metallization.
This document does not specify requirements for hose assemblies; these are detailed in ISO 8207.
This document applies neither to thermoplastics hoses nor to hoses used for high pressure [>0,15 MPa
(>1,5 bar)] acetylene.
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 37, Rubber, vulcanized or thermoplastic — Determination of tensile stress-strain properties
ISO 188, Rubber, vulcanized or thermoplastic — Accelerated ageing and heat resistance tests
ISO 1307:2006, Rubber and plastics hoses — Hose sizes, minimum and maximum inside diameters, and
tolerances on cut-to-length hoses
ISO 1402, Rubber and plastics hoses and hose assemblies — Hydrostatic testing
ISO 10619-1, Rubber and plastics hoses and tubing — Measurement of flexibility and stiffness — Part 1:
Bending tests at ambient temperature
ISO 10619-2, Rubber and plastics hoses and tubing — Measurement of flexibility and stiffness — Part 2:
Bending tests at sub-ambient temperatures
ISO 1817, Rubber, vulcanized or thermoplastic — Determination of the effect of liquids
ISO 4080, Rubber and plastics hoses and hose assemblies — Determination of permeability to gas
ISO 4671, Rubber and plastics hoses and hose assemblies — Methods of measurement of the dimensions of
hoses and the lengths of hose assemblies
ISO 7326, Rubber and plastics hoses — Assessment of ozone resistance under static conditions
ISO 8033, Rubber and plastics hoses — Determination of adhesion between components
© ISO 2018 – All rights reserved 1

---------------------- Page: 13 ----------------------
SIST EN ISO 3821:2020
ISO 3821:2018(E)

ISO 8330, Rubber and plastics hoses and hose assemblies — Vocabulary
ISO 11114-3, Gas cylinders — Compatibility of cylinder and valve materials with gas contents — Part 3:
Autogenous ignition test for non-metallic materials in oxygen atmosphere
ISO 15296, Gas welding equipment — Vocabulary
ISO 23529, Rubber — General procedures for preparing and conditioning test pieces for physical test methods
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 8330 and ISO 15296 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 http: //www .electropedia .org/
3.1
twin hose
two normal rubber hoses joined together longitudinally
3.2
universal fuel gas hose
hose which can be used for all fuel gases except fluxed fuel gas
Note 1 to entry: Fuel gases are listed in Table 5.
3.3
flux fuel gas hose
hose suitable for fuel gas containing a flux
3.4
maximum working pressure
maximum pressure to which the equipment may be subjected in service
4 Abbreviated terms
LPG liquefied petroleum gases
MPS methylacetylene-propadiene mixtures
5 Application
Hoses shall only be used for the gas service for which they are identified (see 10.2).
6 Hose designation
The hoses covered by this document are designated using the following information:
a) inside diameter, see Table 1;
b) light or normal duty (pressure rating), see Table 4;
c) colour and marking (gas service), see Table 5.
EXAMPLE 1 6,3 mm, light duty. Blue (Oxygen).
2 © ISO 2018 – All rights reserved

---------------------- Page: 14 ----------------------
SIST EN ISO 3821:2020
ISO 3821:2018(E)

EXAMPLE 2 10 mm, normal duty. Red and Orange (Universal fuel gases).
EXAMPLE 3 6,3 mm, light duty, FLUX. Red (Fluxed fuel gases).
7 Materials
7.1 Construction
7.1.1 Light and normal duty hoses
The hose shall consist of:
a) a rubber lining of minimum thickness 1,3 mm for hoses with total wall thickness of 3,0 mm or less
and 1,5 mm for hoses with total wall thickness greater than 3,0 mm;
b) reinforcement applied by any suitable technique;
c) a rubber cover of a minimum thickness of 1,0 mm.
7.1.2 Flux fuel gas hose
The flux fuel gas hose shall consist of the following:
a) a rubber lining with an additional inner plastic layer, which shall be of maximum thickness 0,5 mm,
to give a minimum total thickness of a rubber lining of 1,3 mm for hoses with total wall thickness of
3,0 mm or less and 1,5 mm for hoses with total wall thickness greater than 3,0 mm;
b) reinforcement applied by any suitable technique;
c) a rubber cover of minimum thickness 1,0 mm.
7.1.3 Twin hose
Each hose used for twin hose construction shall be as specified in 7.1.1 or 7.1.2. The two hoses shall be
joined longitudinally during the extrusion and/or vulcanization process. They shall be capable of being
separated free of damage to enable end fittings to be fitted (see 9.3.7).
7.2 Manufacture
The lining and cover shall be of uniform thickness and free from holes, porosity and other defects.
8 Dimensions and tolerances
8.1 Inside diameters
The inside diameters of the hoses shall be in accordance with the dimensions and tolerances shown in
Table 1.
© ISO 2018 – All rights reserved 3

---------------------- Page: 15 ----------------------
SIST EN ISO 3821:2020
ISO 3821:2018(E)

Table 1 — Dimensions and tolerances on inside diameter
Inside diameter
Basic dimension Tolerance
Nominal size
mm mm
4,0 4,0
4,8 4,8
5,0 5,0 ±0,4
6,3 6,3
7,1 7,1
8,0 8,0
9,5 9,5 ±0,5
10,0 10,0
12,5 12,5
16,0 16,0
±0,6
20,0 20,0
25,0 25,0
32,0 32,0 ±1,0
40,0 40,0
±1,25
50,0 50,0
NOTE 1  Nominal sizes, basic dimensions and their tolerances on inside diameters do not comply with ISO 1307:2006,
Table 1.
NOTE 2  For intermediate dimensions, numbers are chosen from the R20 series of preferred numbers (see ISO 3) with
tolerances for the next larger inside diameter listed.
8.2 Outside diameters
The basic dimensions of the outside diameters of the hoses shall be determined by the manufacturer
by determining the total wall thickness of the hoses (including rubber lining, rubber cover and
reinforcement layer) relative to the basic dimensions of the inside diameter by the manufacturer. The
tolerances on the basic dimensions of the outside diameters shall be in accordance with the values
shown in Table 2.
Table 2 — Outside diameter ranges and its corresponding tolerance and concentricity
OD range Tolerance on OD Concentricity
maximum
mm mm
Up to and including 12,0 mm ±0,6 0,6
Greater than 12,0 mm up to and including 16,0 mm ±0,8 0,7
Greater than 16,0 mm up to and including 22,5 mm ±1,0 0,8
Greater than 22,5 mm up to and including 42,0 mm ±1,5 1,0
Greater than 42,0 mm ±1,8 1,3
8.3 Wall thickness
The wall thickness of rubber lining, rubber cover and inner plastic layer of the hoses shall be not less
than the minimum thickness specified in 7.1.1 and 7.1.2.
4 © ISO 2018 – All rights reserved

---------------------- Page: 16 ----------------------
SIST EN ISO 3821:2020
ISO 3821:2018(E)

8.4 Concentricity (total indicator reading)
The concentricity of the hose, measured in accordance with ISO 4671, shall be in accordance with the
values given in Table 2.
8.5 Cut lengths and tolerances
The tolerances for cut lengths shall be in accordance with ISO 1307.
8.6 Disclosure of inside diameter and outside diameter
The manufacturer shall indicate the combination of the basic dimensions of the inside diameter and the
outside diameter on the hose as specified in 10.3. In addition, basic dimensions of the inside diameter
and outside diameter of the hose and their permissible tolerances should be disclosed in the documents
such as the catalogues, specifications, instruction manuals and the like.
9 Requirements and type tests
9.1 General
A summary of requirements and type tests with the corresponding number of samples is given in
Annex D.
9.2 Basic requirements
9.2.1 Tensile strength and elongation at break
Measurements shall be made on test pieces cut from the hoses. The materials used in the lining and
cover, when tested in accordance with ISO 37, shall have a tensile strength and elongation at break not
less than the values given in Table 3.
Table 3 — Tensile strength and elongation at break
Rating Tensile strength Elongation at break
MPa %
Rubber lining 5 200
Cover 7 250
Inner plastic layer 5 120
9.2.2 Accelerated ageing
Measurements shall be made on test pieces cut from the hoses. After ageing for 7 days at a temperature
of (70 ± 2) °C as specified in ISO 188 (air oven), the tensile strength and elongation at break respectively
of the lining and cover shall not decrease from the original values obtained by more than 25 % for the
tensile strength and 50 % for elongation at break.
9.2.3 Adhesion
When tested in accordance with ISO 8033 using the type 2 or type 4 test piece, the minimum adhesion
between adjacent components of the hose shall be 1,5 kN/m. For flux fuel gas hoses (see 9.3.4). For flux
fuel gas hoses, the inner plastic layer shall be removed prior to the test.
© ISO 2018 – All rights reserved 5

---------------------- Page: 17 ----------------------
SIST EN ISO 3821:2020
ISO 3821:2018(E)

9.2.4 Hydrostatic requirements
The hose, when tested in accordance with ISO 1402 at ambient temperature, shall meet the requirements
of Table 4.
Table 4 — Hydrostatic requirements
Light duty
Rating Normal duty (all sizes)
(Inside diameter ≤6,3 mm)
Maximum working pressure 1 MPa (10 bar) 2 MPa (20 bar)
Proof pressure 2 MPa (20 bar) 4 MPa (40 bar)
Minimum burst pressure 3 MPa (30 bar) 6 MPa (60 bar)
Change in length at maximum
±5 %
working pressure
Change in diameter at maximum
±10 %
operating pressure
9.2.5 Flexibility at ambient temperature
When tested in accordance with ISO 10619-1 at standard laboratory temperature as defined in
ISO 23529 using a diameter of curvature, D , of 10 D , where D is the inside diameter (with a minimum
c i i
of 80 mm), the coefficient of deformation, K, shall not be less than 0,8. There shall be no kink in the
curved portion of the hose.
9.2.6 Low-temperature flexibility
When tested in accordance with ISO 10619-2, method B, at (−25 ± 3) °C, using a D of 10 D (with a
c i
minimum of 80 mm), the hose shall show no signs of leakage when subjected to the proof pressure
(carried out at ambient temperature) stated in Table 4.
9.2.7 Protection against incandescent particles and hot surfaces
The cover of the hose shall have sufficient protection against contact with incandescent particles and
hot surfaces. To meet th
...