ISO 20826:2006

INTERNATIONAL ISO
STANDARD 20826
First edition
2006-08-15
Automotive LPG components —
Containers
Composants pour véhicules au GPL — Réservoirs

Reference number
©
ISO 2006
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ii © ISO 2006 – All rights reserved

Contents Page
Foreword. iv
1 Scope.1
2 Normative references.1
3 Terms and definitions .2
4 Symbols and abbreviated terms .3
5 Technical requirements.4
5.1 General provisions .4
5.2 Dimensions.4
5.3 Materials.5
5.4 Design temperature .5
5.5 Design pressure.5
6 Construction and workmanship.5
6.1 General requirements.5
6.2 Heat Treatment.5
6.3 Tolerances.6
6.4 Openings.6
6.5 Accessories.6
7 Test Programme.6
7.1 General.6
7.2 Test programme for metal containers .7
7.3 Test programme for all-composite containers .8
7.4 Tests to be performed after design changes.9
8 Marking.10
9 Periodic inspection and re-qualification .10
9.1 Periodic inspection.10
9.2 Re-qualification.10
Annex A (normative) Test methods.13
Annex B (informative) Example of calculations of the pressure-retaining parts of containers.28
Annex C (informative) Welding guidelines .34
Annex D (normative) Tolerance on position of plate or ring .38
Annex E (normative) Location of test samples for metal containers .39
Annex F (normative) Test sample for mechanical tests on metal containers .42
Annex G (normative) Material test methods for all-composite containers .43
Annex H (informative) Example of toric containers.45
Annex I (informative) Example of requirements for performance verification .46
Bibliography .52

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.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
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.
ISO 20826 was prepared by Technical Committee ISO/TC 22, Road vehicles.

iv © ISO 2006 – All rights reserved

INTERNATIONAL STANDARD ISO 20826:2006(E)

Automotive LPG components — Containers
1 Scope
This International Standard specifies the technical requirements for the design and the testing of automotive
Liquefied Petroleum Gas (LPG) containers, to be permanently attached to a motor vehicle which uses
automotive LPG as a fuel.
The technical requirements cover the design criteria, the requirements on construction and workmanship, the
marking and re-qualification procedures.
This International Standard also covers all tests, including their frequencies, to be carried out on autogas
containers, during production and performance verification. Specific recommendations are also given on the
tests to be carried out when changing the design.
2 Normative references
The following referenced documents are indispensable for the application 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 175, Plastics — Methods of test for the determination of the effects of immersion in liquid chemicals
ISO 306, Plastics — Thermoplastic materials — Determination of Vicat softening temperature (VST)
ISO 2504, Radiography of welds and viewing conditions for films — Utilization of recommended patterns of
image quality indicators (I.Q.I.)
ISO 2768-1:1989, General tolerances — Part 1: Tolerances for linear and angular dimensions without
individual tolerance indications
ISO 4136, Destructive tests on welds in metallic materials — Transverse tensile test
ISO 5173, Destructive tests on welds in metallic materials — Bend tests
ISO 6507-1:1997, Metallic materials — Vickers hardness test — Part 1: Test method
ISO 6721 (all parts), Plastics — Determination of dynamic mechanical properties
ISO 6892, Metallic materials — Tensile testing at ambient temperature
ISO 7438, Metallic materials — Bend test
ISO 7799, Metallic materials — Sheet and strip 3 mm thick or less — Reverse bend test
ISO 9328-7, Steel flat products for pressure purposes — Technical delivery conditions — Part 7: Stainless
steels
ISO 9606 (all parts), Approval testing of welders – Fusion welding
ISO 12097-2:1996, Road vehicles — Airbag components — Part 2: Testing of airbag modules
ISO 15614-1:2004, Specification and qualification of welding procedures for metallic materials — Welding
procedure test — Part 1: Arc and gas welding of steels and arc welding of nickel and nickel alloys
ISO 17636, Non-destructive testing of welds — Radiographic testing of fusion-welded joints
ASTM 3039, Fibre-resin composite
ASTM D2343, Standard Test Method for Tensile Properties of Glass Fiber Strands, Yarns and Rovings Used
in Reinforced Plastics
ASTM D2344, Standard Test Method for Short-Beam Strength of Polymer Matrix Composite Materials and
Their Laminates
ASTM D4018.81 Carbon (tens. Prop. Continuous filament)
EN 589, Automotive fuels — LPG — Requirements and test methods
EN 10120, Steel sheet and strip for welded gas cylinders
NOTE ASTM standards are available from ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19424-2959,
USA.
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
test pressure
pressure to which the container is subjected during the test procedure
3.2
design pressure
pressure on which the calculations are based
3.3
container
vessel with all its permanent support(s) and attachment(s) installed, used for the storage of automotive LPG
3.4
cylindrical container
container with a cylindrical shell and two dished ends, either torispherical or elliptical
3.5
metal container
container made only of any suitable metal
3.6
all-composite container
container made only of composite materials without a metallic liner
3.7
batch
maximum of 200 containers of the same type produced consecutively on the same production line
2 © ISO 2006 – All rights reserved

3.8
type of container
container or a group of containers where the individual container does not differ significantly with respect to
the following conditions:
⎯ the manufacturer (different trade names or marks possible);
⎯ the shape;
⎯ the openings;
⎯ the material;
⎯ the welding process (if applicable);
⎯ the heat treatment (if applicable);
⎯ the production line;
⎯ the diameter;
⎯ the height (in case of a toric container — see Annex H);
⎯ the nominal wall thickness.
3.9
longitudinal weld
weld over the full length of the shell or cylindrical part of the shell, excluding welds for fittings
3.10
re-qualification
activities such as examining and testing of the automotive LPG containers, carried out at defined intervals
3.11
parent material
material in the state after transformation necessary for the container manufacturing process
3.12
Liquefied Petroleum Gas
LPG
mixture of light hydrocarbons, gaseous under normal atmospheric conditions which can be liquefied by
increased pressure or decreased temperature, the main components of which are propane, propene, butane
and butene isomers
4 Symbols and abbreviated terms
a is the calculated minimum wall thickness of the cylindrical shell in mm,
b is the calculated wall thickness of the dished ends in mm,
C is the shape factor,
c.g is the centre of gravity,
D is the nominal outside diameter of the container in mm,
F is the force in N,
g is the gravity in m/s ,
h is the height of cylindrical part of dished end in mm,
H is the outside height of dished part of container end in mm,
H is the height of the wedge in mm,
w
L is the length of the edge in mm,
w
n is the ratio between the diameter of the mandrel of the bending test machine and the thickness of the
test sample,
P is the maximum pressure measured in the burst test in MPa,
b
P is the design pressure in MPa,
h
r is the inside knuckle radius of the dished end of the standard cylindrical container in mm,
R is the inside dish radius of the dished end of a standard
...