ISO 16750-4:2010

INTERNATIONAL ISO
STANDARD 16750-4
Third edition
2010-04-15
Road vehicles — Environmental
conditions and testing for electrical and
electronic equipment —
Part 4:
Climatic loads
Véhicules routiers — Spécifications d'environnement et essais de
l'équipement électrique et électronique —
Partie 4: Contraintes climatiques

Reference number
©
ISO 2010
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ii © ISO 2010 – All rights reserved

Contents Page
Foreword .iv
1 Scope.1
2 Normative references.1
3 Terms and definitions .2
4 Operating temperature ranges.2
5 Tests and requirements.3
5.1 Tests at constant temperature .3
5.2 Temperature step test.4
5.3 Temperature cycling tests.5
5.4 Ice water shock test .8
5.5 Salt spray tests .11
5.6 Humid heat, cyclic test.13
5.7 Damp heat, steady-state test.15
5.8 Corrosion test with flow of mixed gas .15
5.9 Solar radiation .16
5.10 Dust test .16
6 Codes for climatic loads.18
7 Protection against dust and water.18
8 Documentation .18
Annex A (informative) Usual tests and requirements for equipment depending on the mounting
location.19
Bibliography.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 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 16750-4 was prepared by Technical Committee ISO/TC 22, Road vehicles, Subcommittee SC 3,
Electrical and electronic equipment.
This third edition cancels and replaces the second edition (ISO 16750-4:2006), which has been technically
revised.
ISO 16750 consists of the following parts, under the general title Road vehicles — Environmental conditions
and testing for electrical and electronic equipment:
⎯ Part 1: General
⎯ Part 2: Electrical loads
⎯ Part 3: Mechanical loads
⎯ Part 4: Climatic loads
⎯ Part 5: Chemical loads
iv © ISO 2010 – All rights reserved

INTERNATIONAL STANDARD ISO 16750-4:2010(E)

Road vehicles — Environmental conditions and testing for
electrical and electronic equipment —
Part 4:
Climatic loads
1 Scope
This part of ISO 16750 applies to electrical and electronic systems/components for road vehicles. This part of
ISO 16750 describes the potential environmental stresses and specifies tests and requirements
recommended for the specific mounting location on/in the road vehicle.
This part of ISO 16750 describes climatic loads.
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 16750-1, Road vehicles — Environmental conditions and testing for electrical and electronic
equipment — Part 1: General
ISO 16750-2, Road vehicles — Environmental conditions and testing for electrical and electronic
equipment — Part 2: Electrical loads
ISO 20653, Road vehicles — Degrees of protection (IP-Code) — Protection of electrical equipment against
foreign objects, water and access
IEC 60068-2-1, Environmental testing — Part 2-1: Tests — Test A: Cold
IEC 60068-2-2, Environmental testing — Part 2-2: Tests — Test B: Dry heat
IEC 60068-2-11, Environmental testing — Part 2-11: Tests — Test Ka: Salt mist
IEC 60068-2-14, Environmental testing — Part 2-14: Tests — Test N: Change of temperature
IEC 60068-2-30, Environmental testing — Part 2-30: Tests — Test Db: Damp heat, cyclic (12 h + 12 h cycle)
IEC 60068-2-38, Environmental testing — Part 2-38: Tests — Test Z/AD: Composite temperature/humidity
cyclic test
IEC 60068-2-52, Environmental testing — Part 2-52: Tests — Test Kb: Salt mist, cyclic (sodium chloride
solution)
IEC 60068-2-60, Environmental testing — Part 2: Tests — Test Ke: Flowing mixed gas corrosion test
IEC 60068-2-78, Environmental testing — Part 2-78: Tests — Test Cab: Damp heat, steady state
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 16750-1 apply.
4 Operating temperature ranges
The applicable operating temperature ranges shall be chosen from Table 1 and shall be given in the
specification of the device under test (DUT).
Table 1 — Operating temperature ranges
Minimum operating temperature Maximum operating temperature
Code T T
min max
°C °C
A −20 65
B −30 65
C 65
D 70
E 75
F 80
G 85
H 90
I 95
J 100
K 105
−40
L 110
M 115
N 120
O 125
P 130
Q 140
R 150
S 155
T 160
Z as agreed upon
In the case of hot-soak requirements, add 15 °C to the maximum operating temperature, T . See 5.3.1.
max
The paint repair temperature, T , can be higher than the operating temperature and shall be given in the
maxPR
specification of the DUT. An applicable test shall be agreed between supplier and vehicle manufacturer.
2 © ISO 2010 – All rights reserved

5 Tests and requirements
5.1 Tests at constant temperature
5.1.1 Low-temperature tests
5.1.1.1 Storage test
5.1.1.1.1 Purpose
This test simulates the exposure of the DUT to low temperatures without electrical operation, e.g. during
shipment of the system/component. Failure mode is insufficient frost resistance, e.g. the freezing of liquid
crystal displays.
5.1.1.1.2 Test method
Perform the test in accordance with IEC 60068-2-1, Test A, at a temperature of −40 °C for a duration of 24 h
unless otherwise specified in the DUT specification. The operating mode of the DUT is 1.1, as defined in
ISO 16750-1.
5.1.1.1.3 Requirement
The minimum functional status shall be class C, as defined in ISO 16750-1.
5.1.1.2 Operation test
5.1.1.2.1 Purpose
This test simulates the exposure of the DUT to low temperatures with electrical operation, e.g. the use of the
system/components at very low ambient temperature. Failure mode is electrical malfunction caused by low
temperature, e.g. the freezing of capacitors with liquid electrolyte.
5.1.1.2.2 Test method
Perform the test in accordance with IEC 60068-2-1, Test A, at the minimum operating temperature, T , for a
min
duration of 24 h. The operating mode of the DUT is 3.2, as defined in ISO 16750-1.
5.1.1.2.3 Requirement
The functional status shall be class A, as defined in ISO 16750-1.
5.1.2 High-temperature tests
5.1.2.1 Storage test
5.1.2.1.1 Purpose
This test simulates the exposure of the DUT to high temperatures without electrical operation, e.g. during the
shipment of the system/component. Failure mode is insufficient heat resistance, e.g. the warping of plastic
housings.
5.1.2.1.2 Test method
Perform the test in accordance with IEC 60068-2-2, Test B, at a temperature of 85 °C for a duration of 48 h
unless otherwise specified in the DUT specification. The operating mode of the DUT is 1.1, as defined in
ISO 16750-1.
5.1.2.1.3 Requirement
The functional status shall be class C, as defined in ISO 16750-1.
5.1.2.2 Operation test
5.1.2.2.1 Purpose
This test simulates the exposure of the DUT to high temperatures with electrical operation, e.g. the use of the
system/components at very high ambient temperature. Failure mode is electrical malfunction caused by high
temperature, e.g. the thermal degradation of components.
5.1.2.2.2 Test method
Perform the test in accordance with IEC 60068-2-2, Test B, at the maximum operating temperature, T , for
max
a duration of 96 h. Use operating mode 3.2, as defined in ISO 16750-1.
5.1.2.2.3 Requirement
The functional status shall be class A, as defined in ISO 16750-1.
5.2 Temperature step test
5.2.1 Purpose
This test checks the mechanical and electrical device for malfunctions which may occur within a small section
of the operating temperature range.
Figure 1 illustrates the temperature step test, using code Q as specified in Table 1.

Key
T temperature, in °C
t time, in min
Figure 1 — Example of temperature step test, using code Q in accordance with Table 1
4 © ISO 2010 – All rights reserved

5.2.2 Test method
Install the DUT in a temperature chamber, decrease the temperature in steps of 5 °C from 20 °C to T , and
min
then increase the temperature in steps of 5 °C from T to T (see Table 1). Wait at each step until the
min max
DUT has reached the new temperature. Perform functional tests operating mode 3.2 in accordance with
ISO 16750-1 at minimum supply voltage, U , and at maximum supply voltage, U , in accordance with
Smin Smax
the specified ISO 16750-2 code letter, at each new temperature step. Switch the DUT off during transition to
the next temperature.
5.2.3 Requirement
The DUT shall take up its normal function at each temperature between T and T , i.e. the functional
min max
status shall be class A, as defined in ISO 16750-1.
5.3 Temperature cycling tests
5.3.1 Temperature cycle with specified change rate
5.3.1.1 Purpose
This test simulates varying temperatures with electrical operation of the DUT, e.g. during the use of the
system/components at changing ambient temperature. If a system/component is exposed to hot-soak
temperatures (e.g. engine-mounted systems/components), an additional short temperature peak is added
during the high-temperature phase of the pr
...