Passenger cars — Windscreen defrosting and demisting systems — Test method

ISO 3468:2014 specifies the test method for passenger car (ISO 3833:1977, 3.1.1) windscreen defrosting and demisting systems, when these are fitted. ISO 3468:2014 does not specify reference areas or levels of performance.

Voitures particulières — Dispositif de dégivrage et de désembuage du pare-brise — Méthode d'essai

General Information

Status
Published
Publication Date
22-May-2014
Current Stage
9093 - International Standard confirmed
Start Date
13-May-2020
Completion Date
13-May-2020
Ref Project

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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)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2014

All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form

or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior

written permission. Permission can be requested from either ISO at the address below or ISO’s member body in the country of

the requester.
ISO copyright office
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Tel. + 41 22 749 01 11
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Published in Switzerland
ii © ISO 2014 – All rights reserved
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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

© ISO 2014 – All rights reserved iii
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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

constitute an endorsement.

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.
iv © ISO 2014 – All rights reserved
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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.
© ISO 2014 – All rights reserved v
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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
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.
© ISO 2014 – All rights reserved 1
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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;
— 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) 1 kPa = 10 bar
2 © ISO 2014 – All rights reserved
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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.

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
...

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