ISO 20826:2006
(Main)Automotive LPG components — Containers
Automotive LPG components — Containers
ISO 20826:2006 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. ISO 20826:2006 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.
Composants pour véhicules au GPL — Réservoirs
General Information
Standards Content (Sample)
INTERNATIONAL ISO
STANDARD 20826
First edition
2006-08-15
Automotive LPG components —
Containers
Composants pour véhicules au GPL — Réservoirs
Reference number
ISO 20826:2006(E)
©
ISO 2006
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ISO 20826:2006(E)
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ii © ISO 2006 – All rights reserved
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ISO 20826:2006(E)
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
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ISO 20826:2006(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.
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.
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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
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ISO 20826:2006(E)
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
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ISO 20826:2006(E)
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,
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ISO 20826:2006(E)
2
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 cylindrical container in mm,
R is the minimum yield stress in MPa guaranteed by the manufacturer of the container, for the parent
e
material,
R is the minimum tensile strength in MPa specified by the material standard,
g
R is the actual tensile strength in MPa,
m
T is the glass transition temperature of the resin matrix, in °C,
g
V is the velocity in km/h,
z is the welding factor,
HV is the Vickers hardness,
PRD is the pressure relief device,
PRV is the pressure relief valve,
UV is Ultra-Violet.
5 Technical requirements
5.1 General provisions
The container for vehicles using automotive LPG in their propulsion system shall function in a correct and safe
way.
Any finished container, randomly chosen, shall comply with the applicable tests as prescribed in Annex A.
All necessary corrosion prevention measures shall be taken to protect the finished container.
5.2 Dimensions
For all dimensions without indication of tolerances, general tolerances of ISO 2768-1 shall apply.
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ISO 20826:2006(E)
5.3 Materials
All materials compatible with LPG, may be used provided that the container complies with the applicable tests
of this International Standard.
For steel, EN 10120 or EN 10028-7 may be used.
The container manufacturer shall ensure that all parent materials are free from defects.
Container parts and filler materials shall be compatible when welded.
For steel welds, ISO 15614-1 shall apply.
The container manufacturer shall maintain records of the results of metallurgical and mechanical tests and
analyses of parent and filler materials as described below:
⎯ for metal containers: chemical cast analysis certificates and mechanical properties for the metal used for
the construction of the parts subject to pressure;
⎯ for all-composite containers: results of tests as prescribed in Annex G.
The container manufacturer shall maintain a system to trace all parent materials for parts subject to pressure.
5.4 Design temperature
The minimum design temperature shall be −20 °C.
The maximum design temperature shall be +65 °C.
For extremely low operating temperature, a minimum design temperature of −40 °C shall be applied. This
lower design temperature shall be indicated on the marking plate.
The manufacturer shall demonstrate that the material from which the pressure-containing parts of the
container are constructed shall have properties suitable for the range of temperatures down to − 40 °C.
5.5 Design pressure
The design pressure of the container shall be 3,0 MPa.
6 Construction and workmanship
6.1 General requirements
The manufacturer shall be able to demonstrate that its quality control system ensures that the containers
produced meet the requirements of this International Standard.
The manufacturer shall maintain records of the processes, procedures, inspections and qualification that are
carried out during production.
It is recommended that the out-of-roundness of the cylindrical shell of the metal container is not more than the
difference between the maximum and minimum outside diameter of the same cross-section and is not more
than 1 % of the average of those diameters.
Unless otherwise shown on the construction drawing, it is recommended that the maximum deviation of the
cylindrical part of the shell from a straight line (straightness) does not exceed 0,3 % of the length of the
cylindrical part.
6.2 Heat treatment
The container manufacturer shall maintain records of the heat treatment procedures on container parts and
finished containers, either completely or localized, necessary to comply with the requirements of this
International Standard.
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ISO 20826:2006(E)
6.3 Tolerances
6.3.1 Capacity
The actual water capacity of the container, shall have a tolerance of −0 % to +3 % compared to the figure
shown on the marking plate.
6.3.2 Position
The tolerance on the position of the valve boss/plate in the container shall be plus or minus 1 degree in two
directions, transverse and twist (see Annex D).
6.4 Openings
Openings shall be provided for filling, off-take, pressure relief and level indication.
Openings for pressure relief valves shall be in the vapour phase, when the container is in its normal mounting
position.
Openings shall be taper threaded or flanged.
Openings may also be provided for power supply, pumps, etc.
Openings for valves may be either separate or combined.
An O-ring may be fitted either in the ring or in the flange, see Figure C.4.
Internal vapour off-take pipework shall be adequately supported and shall end in the vapour space of the
container as high as possible above the maximum filling level.
Internal liquid off-take pipework shall end as low as possible in the container.
6.5 Accessories
Where fitted, the marking plate shall be fixed permanently on the container shell or end. Corrosion prevention
measures shall be taken.
The accessories in and on the container shall be fitted under the responsibility of the holder of the bonfire test
approval certificate (see I.5).
It shall be possible to securely mount a gas-tight housing or other protective device over the container
accessories.
The support(s) shall be manufactured and attached to the container body in such a way as:
⎯ not to cause dangerous concentrations of stresses or be conducive to the collection of water;
⎯ to be strong enough to withstand forces of at least 30 g in all directions for at least 20 ms, to be
demonstrated by impact test or calculation.
7 Test programme
7.1 General
This clause specifies all tests and their frequencies during production and performance verification, applicable
to automotive LPG containers.
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ISO 20826:2006(E)
Tests methods are described in Annex A.
NOTE Performance verification means the demonstration to the competent authorities that the finished container
complies with the design, construction and workmanship requirements of this International Standard.
7.2 Test programme for metal containers
Table 1 — Overview of tests to be performed on metal containers
Performance
Test during Number of containers to
verification Subclause
production be tested
testing
a b
Tensile strength test 1 per batch X 2 A.1.2
b
Bend test 1 per batch X A.1.3
2
Burst test X 2 A.2
All containers submitted for
Pressure test Each container X A.3
performance verification
Leakage test Each container X Each container A.4
b
Hardness test X 2 A.6
Fatigue test X 3 A.7
Bonfire test X 1 A.8
Radiographic examination At least 1 per 100 % of the container
X A.9.2
of welds batch under test
Macroscopic examination
b
1 per batch X 2 A.1.4
of welds
Visual inspection of welds Each container X Each container A.9.1
Visual inspection of
Each container X Each container
container parts
During the performance verification testing, on one of the containers to be tested, the volume of the container and the
wall thickness of each part of the container shall be determined.
The number of test samples for performance verification testing shall be six; they shell be produced consecutively.
NOTE X = test required.
a
Test required.
b
These test pieces can be taken from one container.
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ISO 20826:2006(E)
7.3 Test programme for all-composite containers
Table 2 — Overview of tests to be performed on all-composite containers
Performance
Test during Number of containers to
verification Subclause
production be tested
testing
a
Burst test 1 per batch X 3 A.2
All containers submitted
Pressure tests Each container X for performance A.3
verification
Leakage test Each container X Each container A.4
Ambient temperature pressure
X 3 A.5.1
cycling test
High temperature pressure
X 1 A.5.2
cycling test
Permeation test X 2 A.5.3
LPG cycling test X 1 A.5.4
High temperature creep test X 1 A.5.5
Bonfire test X 1 A.8
Impact test X 1 A.10
Drop test X 2 A.11
Boss torque test X 1 A.12
Acid environment test X 1 A.13
Ultra-violet radiation test X 1 A.14
a Test required.
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ISO 20826:2006(E)
7.4 Tests to be performed after design changes
If the design of a container with recognised performance verification is changed, the performance verification
testing shall be limited to the tests listed in the Table 3.
Table 3 — Overview of tests to be performed after design changes
Design change
a
Fibre manufacturer X X
C C
Fibre material X X X X X X X X X X
C C C C C C C C C C
Resin material X X X X X X X X X X X X X
C C C C C C C C C C C C C
b
Metallic cylinder and/or filler X X X X X X
material
Plastic liner material X X X X X X X X X
C
C C C C C C C C
Nominal wall thickness X X X X X X X X X X X X X X X
C C C C C C C C C C
c
Diameter change u [20%] X X X X
C C
for toric and cylindrical
containers
c
Diameter change >[20%] X X X X X X X
C C C C
for toric and cylindrical
containers
c
Length change u [50%] X X X X
C C
for cylindrical containers
c
Length change >[50%] X X X X X X X
C C C C
for cylindrical containers
c
Height change u [50%] X X X X X
C C C
for toric containers
c
Height change > [50%] X X X X X X X X
C C C C C
for toric containers
Change of container shapes X X X X c X X X X
C C C C C C
Dome shape X X X X X
C C
Opening size X X X X
C
Coating change X X X
End boss design X X X X X
C C
Change in manuf. process X X X X X X X X X
C C C C C
Note X = test required on all types of containers.
Note X = test required only for all-composite containers.
C
a
X = test required only for all-composite containers.
C
b
X = test required on all types of containers.
c
Compliance with the permeation test requirements shall be checked by direct measure or calculation.
© ISO 2006 – All rights reserved 9
Burst test
Tensile strength test
Bend test
Ambient temperature
pressure cycling test
High temperature
cycling test
Fatigue
Hardness test
Permeation test
LPG cycling test
High temperature
creep test
Bonfire test
Impact test
Drop test
Boss torque test
Acid environment
UV
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ISO 20826:2006(E)
8 Marking
The following data shall be marked on the fitting plate or ring or marking plate:
⎯ a serial number;
⎯ the water capacity in litres;
⎯ the marking “LPG”;
⎯ hydraulic test pressure in bar: “xx bar” or MPa: “xx MPa”;
⎯ the wording: “maximum filling: 80 %”;
⎯ year and month of hydraulic testing (e.g. 2002/01);
⎯ approval mark of the country of approval and reference to this International Standard, “ISO 20826:yyyy”;
⎯ diameter (for cylindrical containers) or height (for special containers) or width x length;
NOTE 1 An example of an approval mark is shown in I.5.
⎯ the name or trade mark of the manufacturer (if not permanently marked on the container elsewhere);
⎯ when a pump is mounted in the container, the marking “pump inside” and a marking identifying the pump;
⎯ when a container is designed for temperatures lower than −40 °C, the marking “−40 °C”.
The marking plate shall have enough space to accommodate the re-qualification marks.
A reference mark shall be affixed on the container to ensure its correct orientation when installed.
9 Periodic inspection and re-qualification
9.1 Periodic inspection
The container, permanently attached to a motor vehicle, shall be externally visually inspected during each
periodic inspection of the vehicle, with specific attention to damage, deterioration and corrosion.
The inspection does not require removal of the container from the vehicle unless the inspection authority
decides that the container needs to be externally inspected or hydraulically tested (re-qualified).
9.2 Re-qualification
9.2.1 Re-qualification criteria
Each container shall be re-qualified according to the following criteria:
⎯ not more than 20 years after the year and month of the initial hydraulic test, unless a shorter time
specified by the manufacturer;
⎯ not more than 10 years after the previous re-qualification, unless a shorter time specified by the
manufacturer;
⎯ before re-installing a used container in a vehicle;
⎯ after defects detected during the periodic inspection.
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ISO 20826:2006(E)
Containers fitted in a vehicle involved in a collision shall be visually inspected for damage by a competent
person.
Containers that have been subject or exposed to fire shall be removed from further service.
9.2.2 Re-qualification procedure
The re-qualification procedure shall consist of an external visual inspection and at least one of the following
test procedures:
⎯ a hydraulic test;
⎯ an internal visual inspection.
After each re-qualification, the accessories to the container shall be replaced by new or replacement
components or officially reconditioned accessories.
The re-qualification shall be performed by a competent body, in accordance with the manufacturer’s
instructions related to the accessories.
The competent body shall keep records of the container re-qualifications in relation to the serial number of the
container.
9.2.3 Re-qualification tests
9.2.3.1 External visual inspection
9.2.3.1.1 Test procedure
The container shall be cleaned and have all loose foreign matter removed from its external surface.
The entire surface of the container shall be inspected for damage, deterioration, corrosion and readability of
the markings.
9.2.3.1.2 Interpretation
Containers showing defects shall be removed from further service.
Containers, of which the data cannot be traced, shall be removed from service.
9.2.3.2 Pressure test
The container shall be tested according to A.3.
9.2.3.3 Internal visual inspection
9.2.3.3.1 Test procedure
The containers shall be emptied of liquid and depressurized in a safe and controlled way.
At least one component fitted in or on the container shall be removed.
The container shall be inspected for any sign of corrosion or other defects.
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ISO 20826:2006(E)
9.2.3.3.2 Interpretation
Containers showing sign(s) of internal corrosion that may affect their integrity shall be removed from further
service.
9.2.4 Re-qualification marking
After the successful completion of the re-qualification, the container shall be legibly and durably marked with
the following inform
...
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