ISO 8066-4:2023

INTERNATIONAL ISO
STANDARD 8066-4
First edition
2023-07
Rubber and plastics hoses and
hose assemblies for automotive air
conditioning — Specification —
Part 4:
Low vibration transmission type for
Refrigerant 1234yf
Tuyaux et flexibles en caoutchouc et en plastique pour climatisation
des automobiles — Spécifications —
Partie 4: Type de transmission à faible vibration pour le réfrigérant
1234yf
Reference number
ISO 8066-4:2023(E)
© ISO 2023

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ISO 8066-4:2023(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2023
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
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Published in Switzerland
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ISO 8066-4:2023(E)
Contents Page
Foreword .v
1 Scope . 1
2 Normative references . 1
3  Terms and definitions . 1
4  Classification . 2
4.1 Construction and material . 2
4.2 Pressure class . 2
4.3 Moisture-ingression grades . 2
5 Dimensions .2
5.1 Hose inside diameters . 2
5.2 Hose wall thickness variation . 3
6 Testing and performance requirements . 3
6.1 Test conditions . 3
6.2 Gas leakage . 3
6.2.1 Method A for type test and production test . 3
6.2.2 Procedure for method A . 3
6.2.3 Method B for routine test . 3
6.2.4 Procedure for method B. 4
6.3 Refrigerant permeation . 4
6.3.1 Requirement . 4
6.3.2 Procedure . 4
6.4 Ageing . 4
6.4.1 Requirement . 4
6.4.2 Procedure . 4
6.5 Low-temperature test . 4
6.6 Vacuum resistance . 4
6.6.1 General . 4
6.6.2 Requirement . 4
6.6.3 Procedure . 5
6.7 Length change under pressure . 5
6.7.1 Requirement . 5
6.7.2 Procedure . 5
6.8 Minimum bursting pressure . 5
6.9 Proof pressure . 5
6.10 Extraction by R1234yf . 6
6.11 Ozone resistance . 6
6.12 Hose cleanliness . 6
6.12.1 Requirement . 6
6.12.2 Procedure . 6
6.13 Impulse test . 6
6.13.1 Requirement . 6
6.13.2 Procedure . 6
6.14 Moisture ingression . 7
6.15 Coupling integrity (sealability) . 7
6.16 Vibration transmissibility . 7
7 Frequency of testing . .7
8 Marking . . 8
9 Test report . 8
10 Recommendations for packaging and storage . 8
Annex A (normative) Determination of refrigerant permeation . 9
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ISO 8066-4:2023(E)
Annex B (normative) Low-temperature test .12
Annex C (normative) Determination of amount of matter extracted from hoses by liquid
R1234yf .13
Annex D (normative) Impulse test .14
Annex E (normative) Moisture ingression test .18
Annex F (normative) Coupling integrity (sealability) .22
Annex G (normative) Vibration transmissibility .24
Annex H (normative) Test frequency .27
Annex I (informative) Production tests .28
Bibliography .29
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ISO 8066-4:2023(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
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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 document 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).
ISO draws attention to the possibility that the implementation of this document may involve the use
of (a) patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed
patent rights in respect thereof. As of the date of publication of this document, ISO had not received
notice of (a) patent(s) which may be required to implement this document. However, implementers are
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database available at www.iso.org/patents. ISO shall not be held responsible for identifying any or all
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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.
A list of all parts in the ISO 8066 series can be found on the ISO website.
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.
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INTERNATIONAL STANDARD ISO 8066-4:2023(E)
Rubber and plastics hoses and hose assemblies for
automotive air conditioning — Specification —
Part 4:
Low vibration transmission type for Refrigerant 1234yf
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
ensure national regulatory conditions are taken into consideration.
1 Scope
This document specifies the requirements for rubber hoses and hose assemblies used for low-pressure
application of circulating gaseous Refrigerant 1234yf (tetrafluoropropene) (hereinafter referred to as
R1234yf) in the air-conditioning systems of automobiles. The hoses and hose assemblies are designed in
such a way as to reduce vibration transmission between the engine room and the cabin. The operational
temperature range is −40 °C to +80 °C.
Due to the critical relationship between the hose and coupling for this application, a requirement that
the coupling to be used in service be used for testing is laid down.
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 1402, Rubber and plastics hoses and hose assemblies — Hydrostatic testing
ISO 3448, Industrial liquid lubricants — ISO viscosity classification
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 8330, Rubber and plastics hoses and hose assemblies — Vocabulary
ISO/TR 11340, Rubber and rubber products — Hydraulic hose assemblies — External leakage classification
for hydraulic systems
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 apply.
ISO and IEC maintain terminology 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/
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ISO 8066-4:2023(E)
4  Classification
4.1 Construction and material
The hose shall be built having a suitable seamless synthetic rubber tube. The reinforcement shall
consist of textile yarn, cord or fabric adhered to the tube and cover. The outer cover shall be heat- and
ozone-resistant synthetic rubber (see Figure 1).
Key
1 rubber tube
2 outer cover
3 textile reinforcement
Figure 1 — Hose construction and material
4.2 Pressure class
The pressure class of the hose shall be low pressure class intended for suction applications. The hose
should not be used for high pressure class intended for discharge and liquid applications.
Working pressures are given in Table 1.
Table 1 — Working pressure
Working pressure
Pressure class
a
MPa (bar)
Low 1,06 (10,6)
a 5 2
1 bar = 0,1 MPa = 10 Pa; 1 MPa = 1 N/mm .
4.3 Moisture-ingression grades
4.3.1 ML: low moisture ingression hose as defined in 6.14.
4.3.2 Mm: medium moisture ingression hose as defined in 6.14.
5 Dimensions
5.1 Hose inside diameters
Standard dimensions are given in Table 2. Other dimensions may be used as needed.
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ISO 8066-4:2023(E)
Table 2 — Typical inside diameters
Mean inside diameter
Nominal size
mm
14 14
15 15
16 (5/8) 15,9
19 (3/4) 19
25 (1) 25,4
NOTE Nominal size with parenthesis is based on inch.
5.2 Hose wall thickness variation
When the wall thickness is measured in accordance with ISO 4671, the variation in the wall thickness
shall not exceed the values given in Table 3.
Table 3 — Wall thickness variation
Nominal size Maximum departure from concentricity
mm
Up to and including 19 1,0
Over 19 1,3
6 Testing and performance requirements
6.1 Test conditions
The testing room shall be kept at standard temperature in accordance with ISO 23529. The temperature
of the hoses or hose assemblies shall be stabilized for 24 h before testing.
6.2 Gas leakage
6.2.1 Method A for type test and production test
When determined in accordance with the procedure given in 6.2.2, the loss in mass of refrigerant shall
be no greater than 10 % of the initial mass of the refrigerant and there shall be no visible deterioration
in the hoses or hose assemblies.
6.2.2 Procedure for method A
Test three test pieces. Fill each test piece with R1234yf. Maintain each test piece with the pressure
listed in Table 1 for 24 h at a temperature of (80 ± 2) °C.
This test may be carried out separately or during the 24 h pre-conditioning period for the refrigerant
loss test (see 6.3) at (80 ± 2) °C. When the test is carried out separately from 6.3, use the procedure
described in Annex A.
6.2.3 Method B for routine test
When determined in accordance with the procedure given in 6.2.4, there shall be no leak and no visible
deterioration in the hoses or hose assemblies. When the pricked hose is tested, gas bubbles which
form on the surface of the hose and decrease gradually after pressurizing may be observed but are not
considered to be leakage.
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ISO 8066-4:2023(E)
6.2.4 Procedure for method B
Immerse the test assembly in the water bath. Apply gas (air or inert gases) pressure and maintain the
pressure listed in Table 1 for 5 min. A gas leak detector may also be applied to check leakage under the
pressure listed in Table 1 for 5 min.
6.3 Refrigerant permeation
6.3.1 Requirement
When determined in accordance with the procedure described in 6.3.2, the loss of refrigerant from the
2
hoses or hose assemblies shall be no greater than 5 kg/m /year.
6.3.2 Procedure
Test the hoses or hose assemblies in accordance with the procedure described in Annex A at (50 ± 2) °C.
NOTE The test temperature is specified at 50 °C in consideration of the actual working temperature and the
total operational temperature range.
6.4 Ageing
6.4.1 Requirement
When tested in accordance with 6.4.2, there shall be no leak and no cracks in a test hose or hose
assembly.
6.4.2 Procedure
Wind a hose or hose assembly, of length between 300 mm and 1 000 mm, on to a mandrel having a
diameter eight times the outside diameter of the hose. Place the mandrel and hose or hose assembly in a
circulating-air oven for 168 h at (125 ± 2) °C.
Take the mandrel and hose or hose assembly out of the oven, allow to cool to ambient temperature,
unwind the hose or hose assembly and examine it externally for any cracks, disintegration or other
defects. Then test the hose or hose assembly in accordance with the procedure given in 6.2.3 and 6.2.4.
6.5 Low-temperature test
When tested in accordance with the method described in Annex B, there shall be no leak or loss due to
cracks or splits.
6.6 Vacuum resistance
6.6.1 General
A hose or hose assembly shall be subjected, consecutively, to the vacuum test, then the length variation
test (6.7), followed by the burst test (6.8).
6.6.2 Requirement
The outer diameter d (see Figure 2) shall be more than twice the wall thickness and there shall be
2
no obstruction of flow caused by the hose collapse when the hose or hose assembly is subjected to a
reduced internal pressure (vacuum) of (1,33 ± 0,66) kPa (absolute) for 2 min in accordance with 6.6.3.
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ISO 8066-4:2023(E)
Key
d collapsed hose outside diameter
2
Figure 2 — Definition of the outer diameter d of the collapsed hose
2
6.6.3 Procedure
The test hose or hose assembly shall have a free length of between 610 mm and 1 000 mm. Bend the
hose into a U shape, whereby the internal radius of the base of the U shall be five times the mean outside
diameter of the hose. Apply a vacuum of (1,33 ± 0,66) kPa (absolute) to the bent hose for 2 min. At
the end of this period and while the vacuum is still being applied, measure the minor axis, d , at the
2
base of the U. Check whether d is more than twice the wall thickness and confirm the flow by vacuum
2
application.
6.7 Length change under pressure
6.7.1 Requirement
When subjected to a pressure listed in Table 1, a hose or hose assembly shall not contract by more than
4 % or extend by more than 2 %.
6.7.2 Procedure
Subject the hose or hose assembly, in a horizontal position, to an internal hydrostatic pressure of 7 kPa
1)
(0,07 bar ) and measure the length. Increase the pressure to the prescribed value and measure the
length once again within the following minute. Express the length as a percentage of the length at 7 kPa
(0,07 bar).
Refer to ISO 1402 for additional information.
6.8 Minimum bursting pressure
When determined in accordance with the method described in ISO 1402, using test pieces that have
been subjected to the test for refrigerant loss described in 6.3, the minimum bursting pressure shall be
the value listed in Table 4.
Table 4 — Minimum burst pressure
Minimum burst pressure
Pressure class
MPa (bar)
Low 4,24 (42,4)
6.9 Proof pressure
When tested in accordance with the procedure described in ISO 1402 at the pressure listed in Table 5
and holding the pressure for 2 min ± 30 s, a hose or hose assembly shall exhibit no leakage, cracking,
abrupt distortion (indicating irregularity in materials or manufacture) or other signs of failure.
5 2
1) 1 bar = 0,1 MPa = 10 Pa; 1 MPa = 1 N/mm .
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ISO 8066-4:2023(E)
Table 5 — Proof pressure
Proof pressure
Pressure class
MPa (bar)
Low 2,12 (21,2)
6.10 Extraction by R1234yf
When determined in accordance with Annex C, the quantity of matter extracted from the lining of the
2
hose by the R1234yf shall not exceed 118 g/m .
NOTE The substances extracted will be of an oily or greasy nature.
6.11 Ozone resistance
The test shall be carried out on the hose itself in accordance with ISO 7326. Bend the hose with a bend
radius equal to four times the mean outside diameter and mount on a test piece holder or wind the
hose around a cylinder with a diameter equal to eight times the mean outside diameter specified by the
manufacturer and the test shall be carried out using an ozone concentration of (50 ± 5) mPa.
The hose cover shall exhibit no visible cracks when viewed under ×7 magnification.
6.12 Hose cleanliness
6.12.1 Requirement
The tube of the hose shall be dry and clean. When determined in accordance with 6.12.2, the mass of
2
insoluble matter shall be a maximum of 270 mg/m based on the internal surface area of the hose.
6.12.2 Procedure
Take a hose test piece having a minimum length of 300 mm. Bend the hose into a U shape, with the legs
of the U of equal length. Place the hose in a vertical position and fill the hose with a suitable solvent.
Immediately empty the hose, filtering the solvent through a prepared Gooch crucible, a sintered-glass
crucible or a 0,4 mm filter of known mass.
After drying the filter and residue at approximately 70 °C for 20 min, determine the mass of insoluble
matter by difference.
6.13 Impulse test
6.13.1 Requirement
When tested in accordance with 6.13.2, hoses or hose assemblies shall not leak or fail prior to
150 000 cycles.
6.13.2 Procedure
Carry out the test in accordance with Annex D.
Install a minimum of two hose assemblies on the test apparatus and subject them to a pulsating
pressure listed in Table 6 at 30 cycles per minute to 40 cycles per minute.
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ISO 8066-4:2023(E)
Table 6 — Impulse test conditions
Temperature Test pressure
Pressure class
°C MPa (bar)
Low 100 1,06 (10,6)
6.14 Moisture ingression
When determined in accordance with Annex E, the rate of ingress of moisture shall not exceed the
values listed in Table 7.
Table 7 — Rate of ingression of moisture
Maximum rate of ingress of moisture
Moisture-ingression grades
2
g/mm /year
-4
ML 3,90 × 10
-3
Mm 1,11 × 10
6.15 Coupling integrity (sealability)
The couplings used shall be the same as those intended for use in service.
Carry out the test in accordance with Annex F.
The maximum mass loss per canister (two couplings) per 12-day test shall not exceed 10 g.
None of the four post-exposure flexing evaluations shall produce hissing or visible oil loss at any
location in the coupled assembly.
6.16 Vibration transmissibility
Carry out the test in accordance with Annex G.
Vibration damping as opposed to vibration transmissibility shall exceed the value agreed between the
interested parties.
7 Frequency of testing
Type tests and routine tests shall be as specified in Annex H.
Type tests are those required to confirm that a particular hose or hose assembly design, manufactured
by a particular method from particular materials, meets all the requirements of this document. The
tests shall be repeated at a maximum of five-year interval, or whenever a change in the method of
manufacture or materials used occurs. They shall be performed on all sizes and types except those of
the same size and construction.
Routine tests are those required to be carried out on each length of finished hose or hose assembly
prior to dispatch.
Production tests are those specified in Annex I, which should preferably be carried out to control the
quality of manufacture. The frequencies in Annex I are given as a guide only.
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ISO 8066-4:2023(E)
8 Marking
Except where it is t
...