ISO 2928:2021

INTERNATIONAL ISO
STANDARD 2928
Fourth edition
2021-01
Rubber hoses and hose assemblies
for liquefied petroleum gas (LPG)
in the liquid or gaseous phase and
natural gas up to 2,5 MPa (25 bar) —
Specification
Tuyaux et flexibles en caoutchouc pour gaz de pétrole liquéfié (GPL)
en phase liquide ou gazeuse et le gaz naturel jusqu'à 2,5 MPa (25
bar) — Spécifications
Reference number
©
ISO 2021
© ISO 2021
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ii © ISO 2021 – All rights reserved

Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Classification . 2
5 Materials and construction of hose and hose assembly . 2
6 Dimensions . 3
6.1 Nominal size, inside diameter, outside diameter, minimum bend radius . 3
6.2 Minimum thickness of lining and cover . 4
6.3 Concentricity. 4
6.4 Tolerances in length. 4
7 Physical properties . 4
7.1 Compounds . 4
7.2 Finished hose and hose assemblies . 5
8 Electrical resistance . 6
9 Frequency of testing . 7
10 Marking . 7
10.1 Hoses . 7
10.2 Hose assemblies . 8
Annex A (normative) Flammability test . 9
Annex B (normative) Frequency of testing for type tests and routine tests .11
Annex C (informative) Recommended frequency of testing for production acceptance tests .12
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
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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
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on the ISO list of patent declarations received (see www .iso .org/ patents).
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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 45, Rubber and rubber products,
Subcommittee SC 1, Rubber and plastics hoses and hose assemblies.
This fourth edition cancels and replaces the third edition (ISO 2928:2003), which has been technically
revised.
The main changes compared to the previous edition are as follows:
— renaming of nominal size 9 into nominal size 10 and of nominal size 12 into nominal size 13 in
Tables 1 and 2;
— addition of hoses with a nominal size 10 in Table 1;
— addition of non-pricked hoses in Table 3;
— expansion of the hose/hose assembly classes in Clause 4.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/ members .html.
iv © ISO 2021 – All rights reserved

INTERNATIONAL STANDARD ISO 2928:2021(E)
Rubber hoses and hose assemblies for liquefied petroleum
gas (LPG) in the liquid or gaseous phase and natural gas up
to 2,5 MPa (25 bar) — Specification
WARNING — Persons using this document should be familiar with normal laboratory practice.
This document does not purport to address all of the safety problems, if any, associated with its
use. It is the responsibility of the user to establish appropriate health and safety practices and to
consider any national regulatory conditions.
1 Scope
This document specifies requirements for rubber hoses and rubber hose assemblies used for the transfer
of liquefied petroleum gas (LPG) in the liquid or gaseous phase and natural gas and designed for use at
working pressures ranging from vacuum to a maximum of 2,5 MPa (25 bar) within the temperature
range −30 °C to +70 °C or, for low-temperature hoses (designated -LT), within the temperature range
−50 °C to +70 °C.
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 48-2, Rubber, vulcanized or thermoplastic — Determination of hardness — Part 2: Hardness between
10 IRHD and 100 IRHD
ISO 188, Rubber, vulcanized or thermoplastic — Accelerated ageing and heat resistance tests
ISO 1382, Rubber — Vocabulary
ISO 1402, Rubber and plastics hoses and hose assemblies — Hydrostatic testing
ISO 1817, Rubber, vulcanized or thermoplastic — Determination of the effect of liquids
ISO 4649, Rubber, vulcanized or thermoplastic — Determination of abrasion resistance using a rotating
cylindrical drum device
ISO 4671, Rubber and plastics hoses and hose assemblies — Methods of measurement of the dimensions of
hoses and the lengths of hose assemblies
ISO 6179:2017, Rubber, vulcanized or thermoplastic — Rubber sheets and rubber-coated fabrics —
Determination of transmission rate of volatile liquids (gravimetric technique)
ISO 7233, Rubber and plastics hoses and hose assemblies — Determination of suction resistance
ISO 7326, Rubber and plastics hoses — Assessment of ozone resistance under static conditions
ISO 8031, Rubber and plastics hoses and hose assemblies — Determination of electrical resistance and
conductivity
ISO 8033, Rubber and plastics hoses — Determination of adhesion between components
ISO 8330, Rubber and plastics hoses and hose assemblies — Vocabulary
ISO 10619-1, Rubber and plastics hoses and tubing — Measurement of flexibility and stiffness — Part 1:
Bending tests at ambient temperature
ISO 10619-2:2017, Rubber and plastics hoses and tubing — Measurement of flexibility and stiffness —
Part 2: Bending tests at sub-ambient temperatures
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 1382 and ISO 8330 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/
4 Classification
Hoses and hose assemblies shall be one of the following types:
— type D: delivery hose;
— type D-LT: delivery hose, low-temperature;
— type SD: suction and delivery hose, helix-reinforced;
— type SD-LTR: suction and delivery hose, helix-reinforced, low-temperature (rough-bore).
— type SD-LTS: suction and delivery hose, helix-reinforced, low-temperature (smooth-bore);
All these types can be:
— electrically bonded, in which case the hose is additionally designated and marked with the symbol M;
— electrically conducting by virtue of a conducting rubber layer, in which case the hose is additionally
designated and marked with the symbol Ω;
— electrically discontinuous.
5 Materials and construction of hose and hose assembly
The hose shall consist of the following:
— a lining of rubber resistant to n-pentane;
— a reinforcement of layers of woven, braided or spirally wound textile material or braided or spirally
wound wire;
— a cover of black or coloured synthetic rubber, resistant to abrasion and outdoor exposure;
— for hoses designated M only, they shall additionally have two or more low-resistance electrical-
bonding wires;
— for hoses designated Ω only, cover and/or lining shall be conducting rubber;
— the cover shall be being pricked or unpricked to allow gas permeation; if the cover is unpricked a
comparative measurement of permeation between the rubber materials of cover and lining shall be
carried out, see Table 3.
— for hoses types D and D-LT the materials and construction shall be as described above.
2 © ISO 2021 – All rights reserved

— for types SD, SD-LTR and SD- LTS only, shall additionally have an embedded helical wire reinforcement.
— for type SD-LTR only, an internal, non-embedded helical wire, suitable for −50 °C. For pricked hoses,
the material shall be stainless steel.
Assemblies shall incorporate metallic fittings attached to the hose by the assembler or built in by the
manufacturer. In order to produce the required electrical properties, the couplings should be attached
in accordance with Clause 8.
Chlorinated materials shall not be used in contact with any stainless-steel materials.
6 Dimensions
6.1 Nominal size, inside diameter, outside diameter, minimum bend radius
For hoses without built-in couplings, and when measured in accordance with method A of
ISO 10619-2:2017, the inside diameter and outside diameter and their tolerances shall conform to the
values given in Table 1 or Table 2, depending on the type.
For hoses with built-in couplings, the outside diameters of Table 1 and Table 2 shall not apply.
When tested by the method described in ISO 10619-1, the value of the minimum bend radius shall
conform to the values given in Table 1 or Table 2, depending on the type.
Table 1 — Dimensions of hoses of types D and D-LT
Nominal Inside Outside Design minimum
Tolerance Tolerance
a
size diameter diameter bend radius
mm mm mm mm mm
10 9,7 ±0,5 19,5 ±1,0 90
13 12,7 ±0,5 22,7 ±1,0 100
15 15 ±0,5 25 ±1,
...