ISO 8066-2:2001

Rubber and plastics hoses and hose assemblies for automotive air conditioning - Specification - Part 2: Refrigerant 134a

This part of ISO 8066 specifies the requirements for rubber or thermoplastic hoses and hose assemblies used for circulating liquid and gaseous R134a (tetrafluoroethane) in the air-conditioning systems of automobiles. The hoses and hose assemblies are designed in such a way as to restrict losses of refrigerant and contamination of the system. The operational temperature range is _ 40 °C to +125 °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.

Tuyaux et flexibles en caoutchouc et en plastique pour climatisation des automobiles — Spécifications — Partie 2: Réfrigérant 134a

General Information

• Status: Published
• Publication Date: 19-Sep-2001
• ICS: 43.040.60 - Bodies and body components
• ICS: 83.140.40 - Hoses
• Technical Committee: ISO/TC 45/SC 1 - Rubber and plastics hoses and hose assemblies
• Drafting Committee: ISO/TC 45/SC 1/WG 2 - Automotive hoses
• Current Stage: 9093 - International Standard confirmed
• Start Date: 01-Nov-2021
• Completion Date: 13-Dec-2025

Overview

ISO 8066-2:2001 specifies requirements for rubber and thermoplastic hoses and hose assemblies used to circulate refrigerant R134a (tetrafluoroethane) in automotive air‑conditioning systems. The standard covers design, dimensional limits, classification, and required testing to limit refrigerant loss and system contamination. It applies to hoses and assemblies intended to operate in the range −40 °C to +125 °C and requires that the actual coupling intended for service be used during testing because of the critical hose–coupling interface.

Key Topics and Technical Requirements

• Scope & classification
  • Defines grades A–E (rubber textile‑reinforced, rubber wire‑reinforced, thermoplastic barrier/veneer, thermoplastic covered) and Groups 1–4 (discharge/liquid vs suction, moisture resistance levels).
• Dimensions
  • Prescribes inside and outside diameter tolerances and allowable wall thickness variation for common nominal bores.
• Leakage & refrigerant loss
  • Leakage test: mass loss ≤ 10% of initial refrigerant after conditioning (90 °C) with no visible deterioration.
  • Long‑term refrigerant loss limits (based on internal surface area): at 80 °C - Grades A/B: 29.0 kg/m²·year, Grades C/D/E: 9.7 kg/m²·year; at 90 °C - Grades A/B: 40.0, Grades C/D/E: 30.0.
• Mechanical & environmental tests
  • Ageing: 168 h at 125 °C on a mandrel, followed by 2.4 MPa hydrostatic test.
  • Low‑temperature and ozone resistance tests (normative annexes).
  • Vacuum (reduced pressure): 13.3 kPa ± 6 kPa (absolute) for 2 min; outside diameter reduction ≤ 20%.
  • Length change under pressure: at 2.4 MPa, contraction ≤ 4% or extension ≤ 2%.
  • Bursting pressure: minimum 12 MPa (120 bar) after refrigerant‑loss conditioning.
  • Proof pressure: hold at 50% of burst pressure for 2 min ± 30 s with no leakage.
• Chemical compatibility
  • Extraction limits for material components by R134a and volume change limits for rubber and thermoplastic linings (ISO 1817 method).
• Testing with service couplings
  • Annexes include detailed procedures: refrigerant loss, low‑temperature, extraction, water ingression, coupling integrity, etc.

Applications and Who Uses It

• Automotive OEMs specifying air‑conditioning hose assemblies and connectors
• Hose manufacturers and material suppliers designing R134a service hoses
• Test laboratories and certification bodies performing compliance testing
• Aftermarket parts suppliers and service technicians validating hose replacements
• Regulatory and compliance engineers ensuring refrigerant containment and environmental safety

Related Standards

• ISO 8066‑1 (R12 refrigerant)
• ISO 8330 (vocabulary)
• ISO 1402 (hydrostatic testing)
• ISO 4671 (dimensional measurement)
• ISO 1817 (effect of liquids on rubber)
• SAE J51, SAE J2064 (related refrigerant hose guidance)

Keywords: ISO 8066-2:2001, R134a hose standard, automotive air conditioning hose, refrigerant hose testing, hose assemblies, leak test, burst pressure.

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 8066-2
First edition
2001-09-01
Rubber and plastics hoses and hose
assemblies for automotive air
conditioning — Specification —
Part 2:
Refrigerant 134a
Tuyaux et flexibles en caoutchouc et en plastique pour climatisation des
automobiles — Spécifications —
Partie 2: Réfrigérant 134a
Reference number
©
ISO 2001
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ii © ISO 2001 – All rights reserved

Contents Page
Foreword.iv
1 Scope .1
2 Normative references .1
3 Terms and definitions .2
4 Classification.2
5 Dimensions.3
6 Testing and performance requirements.4
7 Marking .8
Annex A (normative) Determination of refrigerant loss.9
Annex B (normative) Low-temperature test .12
Annex C (normative) Determination of amount of matter extracted from hoses by liquid R134a.13
Annex D (normative) Water ingression test .14
Annex E (normative) Coupling integrity (sealability) .18
Annex F (informative) ISO and SAE refrigerant hose information .20
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 3.
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 part of ISO 8066 may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
International Standard ISO 8066-2 was prepared by Technical Committee ISO/TC 45, Rubber and rubber products,
Subcommittee SC 1, Hoses (rubber and plastics).
ISO 8066 consists of the following parts, under the general title Rubber and plastics hoses and hose assemblies for
automotive air conditioning — Specification:
— Part 1: Refrigerant 12
— Part 2: Refrigerant 134a
Annexes A, B, C, D and E form a normative part of this part of ISO 8066. Annex F is for information only.
iv © ISO 2001 – All rights reserved

INTERNATIONAL STANDARD ISO 8066-2:2001(E)
Rubber and plastics hoses and hose assemblies for automotive air
conditioning — Specification —
Part 2:
Refrigerant 134a
WARNING — Persons using this part of ISO 8066 should be familiar with normal laboratory practice. This
part of ISO 8066 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 compliance
with any national regulatory conditions.
1 Scope
This part of ISO 8066 specifies the requirements for rubber or thermoplastic hoses and hose assemblies used for
circulating liquid and gaseous R134a (tetrafluoroethane) in the air-conditioning systems of automobiles. The hoses
and hose assemblies are designed in such a way as to restrict losses of refrigerant and contamination of the
system. The operational temperature range is � 40 °Cto+125 °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 normative documents contain provisions which, through reference in this text, constitute provisions of
this part of ISO 8066. For dated references, subsequent amendments to, or revisions of, any of these publications
do not apply. However, parties to agreements based on this part of ISO 8066 are encouraged to investigate the
possibility of applying the most recent editions of the normative documents indicated below. For undated
references, the latest edition of the normative document referred to applies. Members of ISO and IEC maintain
registers of currently valid International Standards.
ISO 471:1995, Rubber — Temperatures, humidities and times for conditioning and testing
ISO 1402:1994, Rubber and plastics hoses and hose assemblies — Hydrostatic testing
ISO 1817:1999, Rubber, vulcanized — Determination of the effect of liquids
ISO 3448:1992, Industrial liquid lubricants — ISO viscosity classification
ISO 4671:1999, Rubber and plastics hoses and hose assemblies — Methods of measurement of dimensions
ISO 6803:1994, Rubber or plastics hoses and hose assemblies — Hydraulic-pressure impulse test without flexing
ISO 7326:1991, Rubber and plastics hoses — Assessment of ozone resistance under static conditions
ISO 8330:2001, Rubber and plastics hoses and hose assemblies — Vocabulary
SAE J51:1998, Refrigerant 12 Automotive Air-Conditioning Hose
SAE J2064:1999, R134a Refrigerant Automotive Air-Conditioning Hose
3 Terms and definitions
For the purposes of this part of ISO 8066, the terms and definitions given in ISO 8330 apply.
4 Classification
4.1 Grades
4.1.1 Grades A1 and A2 — Rubber, textile-reinforced
Hoses having a seamless, rubber lining, a reinforcement consisting of textile yarn, cord or fabric bonded to the
lining and cover, and an outer cover of heat- and ozone-resistant rubber.
NOTE Commercial products normally offered for grade A1 hoses have a one-braid reinforcement of textile yarn and an
outside diameter smaller than that of grade A2 hoses. Grade A2 hoses are a two-braid hose. Hose fittings for grade A1 and A2
hoses are not normally interchangeable.
4.1.2 Grade B — Rubber, wire-reinforced
Hoses having a seamless, rubber lining, a reinforcement consisting of wire, and a cover consisting of a heat-
resistant textile yarn impregnated with a rubber cement.
4.1.3 Grade C — Thermoplastic-barrier, textile-reinforced, rubber-covered
Hoses having a lining comprising a thermoplastic barrier with a layer of rubber on each side, a reinforcement
consisting of textile yarns, and a cover of heat- and ozone-resistant rubber.
4.1.4 Grade D — Thermoplastic-veneer, textile-reinforced, rubber-covered
Hoses having a rubber lining with a thin thermoplastic veneer on the inside (fluid side), a reinforcement consisting
of textile yarn, cord or fabric bonded to the lining and cover, and a cover of heat- and ozone-resistant rubber.
4.1.5 Grade E — Thermoplastic, textile-reinforced, thermoplastic-covered
Hoses having a seamless thermoplastic inner lining, a reinforcement consisting of textile yarn, cord or fabric
bonded to the lining and cover, and a cover of heat- and ozone-resistant thermoplastic.
4.2 Groups
4.2.1 Group 1 — Discharge/liquid, moisture-resistant
Hoses for use in discharge/liquid applications that have moisture resistance as defined in 6.15.
4.2.2 Group 2 — Discharge/liquid, medium moisture-resistant
Hoses for use in discharge/liquid applications that have medium moisture resistance as defined in 6.15.
4.2.3 Group 3 — Suction, moisture-resistant
Hoses for use in suction applications that have moisture resistance as defined in 6.15.
4.2.4 Group 4 — Suction, medium moisture-resistant
Hoses for use in suction applications that have medium moisture resistance as defined in 6.15.
2 © ISO 2001 – All rights reserved

5 Dimensions
5.1 Hose inside and outside diameters
When measured in accordance with method 2 of ISO 4671:1999, the hose inside diameter shall conform to the
requirements given in Table 1. When measured in accordance with method 1 of ISO 4671:1999, the hose outside
diameter shall conform to the requirements given in Table 2.
Table 1 — Inside diameter
Dimensions in millimetres
Inside diameter
Nominal
Grade A1 Grade A2 Grade B Grade C Grade D Grade E
bore
min. max. min. max. min. max. min. max. min. max. min. max.
4,8 4,8 5,4 4,6 5,1
6,4 6,2 7,0 6,1 6,7
8 7,8 8,6 7,8 8,6 8,0 8,7 7,8 8,6 8,0 8,7 7,6 8,3
9,5 9,1 9,9
10 10,2 11,1 10,2 11,1 10,3 11,1 10,2 11,1 10,3 11,1 9,9 10,7
13 12,4 13,6 12,4 13,6 12,7 13,7 12,4 13,6 12,7 13,7 12,2 13,2
16 15,6 16,8 15,6 16,8 15,9 16,9 15,6 16,8 15,9 16,9 15,2 16,5
22 22,2 23,3 22,2 23,3
29 28,6 29,8 28,6 29,8
Table 2 — Outside diameter
Dimensions in millimetres
Outside diameter
Nominal
Grade A1 Grade A2 Grade B Grade C Grade D Grade E
bore
min. max. min. max. min. max. min. max. min. max. min. max.
4,8 12,7 13,7 8,3
6,4 13,5 15,1 11,4
8 17,5 19,1 18,3 19,8 16,7 17,6 18,3 19,8 16,7 17,6 13,5
9,5 15,2
10 21,4 23,0 22,2 23,8 18,9 20,0 22,2 23,8 18,9 20,0 16,1
13 23,8 25,4 24,6 26,2 22,8 24,0 24,6 26,2 22,8 24,0 18,8
16 27,8 28,5 27,8 29,4 26,8 28,0 27,8 29,4 26,8 28,0 23,4
22 30,6 32,2 30,6 32,2
29 37,3 38,9 37,3 38,9
5.2 Hose wall thickness variation
When the wall thickness is measured in accordance with method 2 of ISO 4671:1999, the variation in the wall
thickness shall not exceed the values given in Table 3.
Table 3 — Wall thickness variation
Grades A, B, C and D Grade E
Nominal bore Maximum departure from Nominal bore Maximum departure from
concentricity concentricity
mm mm
4,8 and 6,4 0,8 4,8 and 6,4 0,5
8to22 1,0 8to13 0,6
29 1,3 16 0,8
6 Testing and performance requirements
6.1 Test conditions and test fluid
The testing room shall be kept at standard temperature in accordance with ISO 471. The temperature of the hoses
or hose assemblies shall be stabilized for 24 h before testing.
Except for the extraction test in 6.10 which uses refrigerant R134a only, the refrigerant used shall be R134a
containing (10� 1) % of poly(alkylene glycol) (PAG) lubricating oil when required. The hose shall be tested with the
same couplings as those intended for end use. The end termination of the coupling may be of a convenient type for
testing.
6.2 Leakage
6.2.1 Requirement
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
Test three test pieces. Fill each test piece with R134a containing (10� 1) % PAG oil. Maintain each test piece for
24 h at a temperature of 90 °C� 2 °C.
NOTE This test may be carried out separately or during the 24 h pre-conditioning period for the refrigerant loss test (see
6.3) at 90 °C � 2 °C.
In the event that the test is carried out separately from 6.3, use the procedure described in annex A.
6.3 Refrigerant loss
6.3.1 Requirement
When determined in accordance with the procedure described in 6.3.2, the loss of refrigerant from the hoses or
hose assemblies shall be no greater than the values given in Table 4.
4 © ISO 2001 – All rights reserved

6.3.2 Procedure
Test the hoses or hose assemblies in accordance with the procedure described in annex A at the temperature
specified in Table 4. Test hoses or hose assemblies used in the part of the system operating at high pressure at
90 °C� 2 °C. Test hoses or hose assemblies used in the part of the system operating at low pressure (suction line
applications) at 80 °C� 2 °C.
Table 4 — Refrigerant loss
a
Maximum allowable loss of refrigerant
Test temperature
kg/m /year
°C
Grades A and B Grades C, D and E
80 29,0 9,7
90 40,0 30,0
a
Based on the internal surface area of the hose.
6.4 Ageing
6.4.1 Requirement
When tested in accordance with 6.4.2, there shall be no leak or loss during the test from 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 °C� 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. Subject the hose or
hose assembly to an internal hydrostatic pressure of 2,4 MPa (24 bar) for 5 min to show any leak or loss of liquid.
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 Reduced pressure
6.6.1 General
A hose or hose assembly shall be subjected, consecutively, to the reduced-pressure test, then the length variation
test (6.7), then the burst test (6.8).
6.6.2 Requirement
The decrease in the outside diameter of the hose shall not exceed 20 % of the initial outside diameter when the
hose or hose assembly is subjected to a reduced internal pressure (vacuum) of 13,3 kPa� 6 kPa (absolute) for
2 min in accordance with 6.6.3.
6.6.3 Procedure
The test hose or hose assembly shall have a free length of from 610 mm to 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 13,3 kPa� 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 outside diameter of the hose at the base of the U, in order to
determine the minimum outside diameter at that point.
6.7 Length change under pressure (see 6.6)
6.7.1 Requirement
When subjected to a pressure of 2,4 MPa (24 bar), 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 (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 (see 6.6)
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 12 MPa (120 bar)
for all grades and sizes of hose and hose assembly.
6.9 Proof pressure
6.9.1 Requirement
When tested in accordance with the procedure described in 6.9.2, a hose or hose assembly shall exhibit no
leakage, cracking, abrupt distortion (indicating irregularity in materials or manufacture) or other signs of failure.
6.9.2 Procedure
Hydrostatically pressurize a hose or hose assembly to 50 % of the minimum burst pressure and hold the pressure
for 2 min� 30 s. During and after the proof pressure hold period, examine the hose.
6.10 Extraction by R134a
When determined in accordance with annex C, the quantity of matter extracted from the lining of the hose by the
R134a shall not exceed 118 g/m .
NOTE The substances extracted will be of an oily or greasy nature.
6.11 Volume change in R134a
6.11.1 General
This requirement applies only to the lining of the hose and is carried out by the method described in ISO 1817.
Place a test portion of the lining in a pressure vessel, cooled to below � 30 °C and totally immersed in R134a
containing (10� 1) % PAG oil. Seal the vessel and place it in a circulating-air oven at 90 °C� 2 °C.
6 © ISO 2001 – All rights reserved

6.11.2 Rubber materials
When the test is carried out in accordance with ISO 1817 for 70 h at 90 °C� 2 °C in R134a containing (10� 1) %
PAG oil, the volume change measured during the 5 min after taking the test portion out of the refrigerant shall be
between�5% and+35%.
6.11.3 Thermoplastic materials
When the test is carried out in accordance with ISO 1817 for 70 h at 90 °C� 2 °C in R134a containing (10� 1) %
PAG oil, the volume change measured during the 5 min after taking the test portion out of the refrigerant shall be
within�5%.
6.12 Ozone resistance
This requirement applies only to grade A, C, D and E hoses.
Bend the hose around a mandrel with a diameter equal to eight times the mean outside diameter of the hose, and
carry out the test in accordance with method 1 of ISO 7326:1991 using an ozone concentration of 50 mPa�5mPa.
The hose cover shall exhibit no visible cracks when viewed under � 2 magnification.
6.13 Hose cleanliness
6.13.1 Requirement
The tube of the hose shall be dry and clean. When determined in accordance with 6.13.2, the mass of insoluble
matter shall be a maximum of 270 mg/m based on the internal surface area of the hose.
6.13.2 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 solvent suitable as a substitute for
trichlorotrifluorethane (CFC113).
The following solvents can be used as substitutes for trichlorotrifluorethane (this is only a partial list of acceptable
substitutes, and other materials may be more readily available):
� N-propyl bromide, which is manufactured by Amity under the trade name Leksol;
� hydrofluoroether, which is manufactured by 3M under the trade name HFE 7100;
� decafluoropentane/dichloroethylene blend, which is manufactured by DuPont under the trade name Vertrel
MCA.
NOTE Trichlorotrifluorethane used to be the recommended solvent for this test, but it is not available for most applications
and in many locations since it has been identified as an ozone-depleting chemical.
Immediately empty the hose, filtering the solvent through a prepared Gooch crucible, a sintered-glass crucible or a
0,4�m 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.
6.14 Impulse test
6.14.1 Requirement
When tested in accordance with 6.14.2, hoses or hose assemblies shall not leak or fail after 150 000 cycles.
6.14.2 Procedure
Carry out the test in accordance with ISO 6803.
Install a minimum of two hoses or hose assemblies on the test apparatus and subject them to a pulsating pressure
of 500 kPa� 500 kPa (5 bar� 5 bar) to 2,6 MPa� 130 kPa (26 bar� 1,3 bar) at 30 cycles to 40 cycles per min.
Use oil conforming to ISO VG 46 at 40 °C in accordance with ISO 3448. Perform the test at 125 °C� 2 °C.
Use a minimum bend radius of five times the outside diameter of the hose.
6.15 Water ingress test
When determined in accordance with annex D, the rate of ingress of moisture shall not exceed the values listed in
Table 5.
Table 5 — Rate of ingress of moisture
Maximum rate of ingress of moisture
Hose
g/mm /year
�4
Moisture-resistant hose 3,90 � 10
�3
Medium moisture-resistant hose 1,11 � 10
6.16 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 E.
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.
7 Marking
Except where it is too small to label, the hose or hose assembly shall be marked with the following minimum
information:
a) the manufacturer's name and trademark;
b) the number of this part of ISO 8066, i.e. ISO 8066-2:2001;
c) the grade of hose;
d) the group of hose;
e) the nominal bore of the hose;
f) the name of the refrigerant, i.e. "R134a";
g) the month and year of manufacture.
EXAMPLE MAN/ISO 8066-2/A2/1/16/R134a/09/0
...