ISO 3468:2014

INTERNATIONAL ISO
STANDARD 3468
Third edition
2014-06-01
Passenger cars — Windscreen
defrosting and demisting systems —
Test method
Voitures particulières — Dispositif de dégivrage et de désembuage du
pare-brise — Méthode d’essai
Reference number
ISO 3468:2014(E)
©
ISO 2014

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ISO 3468:2014(E)

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© ISO 2014
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ISO 3468:2014(E)

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Test method for defrosting systems . 2
4.1 Performance requirements . 2
4.2 Test equipment . 2
4.3 Test preparation . 2
4.4 Test condition . 3
4.5 Test procedure . 3
5 Test method for demisting systems . 4
5.1 Performance requirements . 4
5.2 Test equipment . 5
5.3 Test preparation . 5
5.4 Test conditions . 7
5.5 Test procedure . 7
Annex A (informative) Recommended method of recording cleared area .9
Bibliography .10
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ISO 3468:2014(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.
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 documents 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).
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. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www.iso.org/patents).
Any trade name used in this document is information given for the convenience of users and does not
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For an explanation on the meaning of ISO specific terms and expressions related to conformity
assessment, as well as information about ISO’s adherence to the WTO principles in the Technical Barriers
to Trade (TBT) see the following URL: Foreword - Supplementary information
The committee responsible for this document is ISO/TC 22, Road vehicles, Subcommittee SC 17, Visibility.
This third edition cancels and replaces ISO 3468:1989 and ISO 3470:1989, which have been technically
revised.
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ISO 3468:2014(E)

Introduction
It is not necessary for the tests specified in Clauses 4 and 5 to be repeated on types of power-driven
vehicles which do not differ from one another in respect of the following essential features, which affect
defrosting/demisting performance:
a) shape, size, and surface characteristics of the windscreen;
b) characteristics of each system designated by the vehicle manufacturer as contributing to windscreen
defrosting/demisting;
c) number of seats as designated by the vehicle manufacturer.
It can be possible to carry out tests of a similar nature on front windscreens and rear-windows
simultaneously.
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INTERNATIONAL STANDARD ISO 3468:2014(E)
Passenger cars — Windscreen defrosting and demisting
systems — Test method
1 Scope
This International Standard specifies the test method for passenger car (ISO 3833:1977, 3.1.1) windscreen
defrosting and demisting systems, when these are fitted.
This International Standard does not specify reference areas or levels of performance.
The test condition of −18 °C ± 3 °C specified for defrosting systems will meet the majority of cold climatic
requirements.
The tests for demisting systems are conducted at a temperature of −3°C ± 1°C, since this is the practical
minimum temperature at which mist, as defined in 3.7, can normally occur.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.
ISO 1176:1990, Road vehicles — Masses — Vocabulary and codes
ISO 3833:1977, Road vehicles — Types — Terms and definitions
1)
ISO 6549:1980, Road vehicles — Procedure for H-point determination
3 Terms and definitions
For the purposes of this document, the following definitions apply.
3.1
defrosted area
area of the outer glazed surface of the windscreen having a dry surface or covered with melted or
partially melted (wet) frost, excluding any area of the windscreen covered with dry frost
3.2
defrosting
elimination of frost and/or ice covering the outer glazed surface of the windscreen by the operation of
the windscreen defrosting and/or windscreen wiping and washing systems
3.3
windscreen defrosting system
device, or combination of devices, intended by the vehicle manufacturer to eliminate frost or ice from the
glazed surfaces of the windscreen and thus restore visibility, together with the necessary accessories
and controls
3.4
windscreen wiping system
device for wiping the windscreen outer glazed surface, together with the necessary accessories and
controls
1) From 2021-06-01, ISO 20176 will cancel and replace ISO 6549:1999.
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ISO 3468:2014(E)

3.5
windscreen washing system
device for storing washer solution and applying it to the windscreen outer glazed surface together with
the necessary controls
3.6
road load
power output, as indicated by the vehicle manufacturer, required to move the vehicle on a flat road at a
specified speed through still air at 20 °C, with a standard barometric pressure of 1 013 mbar; the mass
of the vehicle being equal to the complete vehicle kerb mass, in accordance with ISO 1176 (ISO-M06) plus
150 kg, i.e. representing the driver and passenger on the front seats
Note 1 to entry: Road load takes account of transmission friction, rolling friction, and air resistance.
3.7
mist
film of condensate on interior glazed surface
3.8
demisting
elimination of mist from the windscreen by the operation of the windscreen demisting system
3.9
windscreen demisting system
device, or combination of devices, intended by the vehicle manufacturer to remove mist from the
windscreen and thus restore visibility, together with the necessary accessories and controls
4 Test method for defrosting systems
4.1 Performance requirements
When tested in accordance with the following procedure, and at the temperature specified, the defrosting
system shall be capable of defrosting specified percentages of specified areas after stated time intervals
from the start of the test.
4.2 Test equipment
4.2.1 Cold chamber, large enough to contain the complete vehicle and capable of ensuring that
temperatures of either −8 °C ± 2 °C or −18 °C ± 3 °C can be maintained throughout the test.
4.2.2 Spray gun, capable of applying liquid to the outer glazed surface of the windscreen and having the
following characteristics:
— nozzle diameter: 1,7 mm;
2)
— operating pressure: 350 kPa ± 20 kPa;
— nominal flow rate: 395 ml/min;
— projection cone diameter at 200 mm from nozzle: 300 mm.
4.3 Test preparation
4.3.1 Carry out all necessary vehicle preparation, e.g. cleaning and marking (if required) of the
windscreen and installation of necessary instrumentation to ensure a satisfactory test and to record the
test conditions, prior to the temperature stabilization in 4.3.4.
-2
2) 1 kPa = 10 bar
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ISO 3468:2014(E)

4.3.2 Thoroughly degrease the outer and inner glazed surfaces using an appropriate degreasing agent.
When dry, apply a 3 % to 10 % solution of ammonia in water, allow to dry, and, finally, wipe with a dry
cotton cloth or paper towel that contains no additives.
4.3.3 Ensure that the chamber (4.2.1) is at or below the specified test temperature before the start of
the stabilizing period.
4.3.4 In the case of an electric vehicle or a plug-in hybrid electric vehicle, the high voltage battery should
be fully charged prior to soaking.
4.3.5 Place the vehicle in the chamber (4.2.1). Maintain the temperature in the chamber throughout the
soak and test periods at either
a) −18 °C ± 3 °C, full temperature range, or
b) −8 °C ± 2 °C, restricted temperature range.
4.3.6 Keep the vehicle, with the engine stopped, at the specified test temperature for a period of 10 h.
This period can be shortened if instruments are available to check that the engine coolant, lubricant, and
vehicle internal air have stabilized at the specified test temperature.
4.4 Test condition
4.4.1 Measure the chamber temperature at the same height as the middle of the windscreen at a
location, such that the temperature is not significantly affected by heat from the vehicle under test or by
cold air entering the chamber.
4.4.2 Measure the horizontal component of the air velocity; cooling the chamber immediately prior to
the test, at a point located on the longitudinal centreline of the vehicle, 300 mm ahead of the base of the
windscreen, at a level half-way between the windscreen top and bottom. The velocity of this component
shall be as low as possible and in any case less than 8 km/h.
4.5 Test procedure
4.5.1 Set the vehicle defrosting system controls (see 3.3) for maximum defrost as recommended by the
vehicle manufacturer.
2
4.5.2 After the temperature stabilization in 4.3.5, create an even coating of frost of 0,044 g/cm over
the entire outer glazing surface of the windscreen by means of the spray gun (4.2.2).
4.5.3 The engine bonnet (hood), doors, windows, and
...