Bsi bs en 60068 2 78 2013

60068-2-78  IEC:2012 – 5 – INTRODUCTION This part of IEC 60068 provides a test method of high humidity at constant temperature without condensation on the specimen over a prescribed pe

BSI Standards Publication

Environmental testing

Part 2-78: Tests — Test Cab: Damp heat, steady state

BS EN 60068-2-78:2013

National foreword

This British Standard is the UK implementation of EN 60068-2-78:2013 It is identical to IEC 60068-2-78:2012 It supersedes BS EN 60068-2-78:2002, which will be withdrawn on 3 December 2015

The UK participation in its preparation was entrusted to Technical Committee GEL/104, Environmental conditions, classification and testing

A list of organizations represented on this committee can be obtained on request to its secretary

This publication does not purport to include all the necessary provisions of a contract Users are responsible for its correct application

© The British Standards Institution 2013

Published by BSI Standards Limited 2013 ISBN 978 0 580 72152 6

ICS 19.040; 29.020

Compliance with a British Standard cannot confer immunity from legal obligations.

This British Standard was published under the authority of the Standards Policy and Strategy Committee on 31 July 2013

Date Text affected

BRITISH STANDARD

BS EN 60068-2-78:2013

NORME EUROPÉENNE

CENELEC European Committee for Electrotechnical Standardization Comité Européen de Normalisation Electrotechnique Europäisches Komitee für Elektrotechnische Normung

Management Centre: Avenue Marnix 17, B - 1000 Brussels

© 2013 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members

Ref No EN 60068-2-78:2013 E

English version

Environmental testing - Part 2-78: Tests - Test Cab: Damp heat, steady state

(IEC 60068-2-78:2012)

Essais d'environnement -

Partie 2-78: Essais -

Essai Cab: Chaleur humide, essai continu

(CEI 60068-2-78:2012)

Umgebungseinflüsse - Teil 2-78: Prüfverfahren - Prüfung Cab: Feuchte Wärme, konstant (IEC 60068-2-78:2012)

This European Standard was approved by CENELEC on 2012-12-03 CENELEC members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration

Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CENELEC member

This European Standard exists in three official versions (English, French, German) A version in any other language made by translation under the responsibility of a CENELEC member into its own language and notified

to the CEN-CENELEC Management Centre has the same status as the official versions

CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom

EN 60068-2-78:2013 - 2 -

Foreword

The text of document 104/582/FDIS, future edition 2 of IEC 60068-2-78, prepared by IEC/TC 104

"Environmental conditions, classification, and methods of test" was submitted to the IEC-CENELEC parallel vote and approved by CENELEC as EN 60068-2-78:2013

The following dates are fixed:

• latest date by which the document has

to be implemented at national level by

publication of an identical national

standard or by endorsement

(dop) 2013-12-14

• latest date by which the national

standards conflicting with the

document have to be withdrawn

(dow) 2015-12-03

This document supersedes EN 60068-2-78:2001

EN 60068-2-78:2013 includes the following significant technical changes with respect to

EN 60068-2-78:2001:

The test chamber from EN 60068-3-6 has been introduced

Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights CENELEC [and/or CEN] shall not be held responsible for identifying any or all such patent rights

Endorsement notice

The text of the International Standard IEC 60068-2-78:2012 was approved by CENELEC as a European Standard without any modification

BS EN 60068-2-78:2013

- 3 - EN 60068-2-78:2013

Annex ZA

(normative)

Normative references to international publications with their corresponding European publications

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

NOTE When an international publication has been modified by common modifications, indicated by (mod), the relevant EN/HD applies

IEC 60068-1 - Environmental testing -

Part 1: General and guidance EN 60068-1 -

IEC 60068-3-6 - Environmental testing -

Part 3-6: Supporting documentation and guidance - Confirmation of the performance

of temperature/humidity chambers

EN 60068-3-6 -

IEC Guide 104 - The preparation of safety publications and

the use of basic safety publications and group safety publications

– 2 – 60068-2-78  IEC:2012

CONTENTS

INTRODUCTION 5

1 Scope and object 6

2 Normative references 6

3 Terms and definitions 6

4 General test procedure 6

Test chamber and measuring system 6

4.1 Severity 7

4.2 Pre-conditioning 7

4.3 Testing procedure 7

4.4 Recovery procedure 8

4.5 5 Measurements 8

Initial measurements 8

5.1 Intermediate measurements 8

5.2 Final measurements 8

5.3 6 Information to be given in the relevant specification 8

7 Information to be given in the test report 9

Table 1 – Temperature and relative humidity 7

BS EN 60068-2-78:2013

60068-2-78  IEC:2012 – 5 –

INTRODUCTION

This part of IEC 60068 provides a test method of high humidity at constant temperature without condensation on the specimen over a prescribed period This test is performed to evaluate the specimen as it is influenced by the absorption and diffusion of moisture and moisture vapour

– 6 – 60068-2-78  IEC:2012

ENVIRONMENTAL TESTING – Part 2-78: Tests – Test Cab: Damp heat, steady state

1 Scope and object

This part of IEC 60068 establishes a test method for determining the ability of components or equipment to withstand transportation, storage and use under conditions of high humidity The object of this standard is to investigate the effect of high humidity at constant temperature without condensation on a specimen over a prescribed period

It is applicable to small equipment or components as well as large equipment, and can be applied to both heat-dissipating and non-heat-dissipating specimens

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

IEC 60068-1, Environmental testing – Part 1:General and guidance

IEC 60068-3-6, Environmental testing – Part 3-6: Supporting documentation and guidance –

Confirmation of the performance of temperature and humidity chambers

IEC Guide 104, The preparation of safety publications and the use of basic safety publications

and group safety publications

3 Terms and definitions

None

4 General test procedure

Test chamber and measuring system

4.1

The temperature and humidity chamber shall be constructed and verified in accordance with specifications IEC 60068-3-6

The chamber and measuring system shall be such that

– sensing devices can be located in the working space to monitor the temperature and humidity,

NOTE For heat-dissipating specimens, the temperature and humidity near the specimen may be influenced by the effect of heat dissipation from the specimen

– condensed water is drained from the chamber and not re-used unless purified,

– no condensed water from the walls and roof of the test chamber can fall on the specimen(s),

BS EN 60068-2-78:2013

60068-2-78  IEC:2012 – 7 –

– water utilized to maintain humidity levels has electrical conductivity of not more than

20 µS/cm,

– the specimen under test shall not be subjected to radiant heat from the chamber conditioning devices,

– injected moisture, when applicable, is injected remotely from the specimen and without being directly on it,

– the volume of the test chamber is at least five times the total volume of the specimen under test,

– a mounting device, when used, has minimum influence on the heat and humidity exchanges between specimen and surrounding conditions, unless otherwise specified in the relevant specification

Severity

4.2

The test severity is defined by a combination of temperature, relative humidity (RH) and total test duration Unless otherwise specified in the relevant specification, temperature and RH severities may be selected from the following:

Table 1 – Temperature and relative humidity

Temperature

°C Relative humidity

% RH

Preferred test durations are: 12 h, 16 h, 24 h; 2 days, 4 days, 10 days, 21 days or 56 days The total temperature tolerance of ± 2 K is intended to take account of absolute errors in the measurement, slow changes of temperature and temperature variations of the working space However, in order to maintain the RH within the required tolerances, it is necessary to keep the temperature difference between any two points in the working space at any moment within narrower limits The required humidity conditions will not be achieved if such temperature differences exceed 1 K It may also be necessary to keep short-term fluctuations within

± 0,5 K to maintain the required humidity

Pre-conditioning

4.3

The relevant specification may call for pre-conditioning

Testing procedure

4.4

The specimen shall be introduced into the chamber as required by the relevant specification The specimen shall be introduced in the unpacked, switched-off, ready-for-use state, or as otherwise specified in the relevant specification

In certain cases the relevant specification may allow the introduction of the specimen in the chamber when this is already in the condition prescribed for the test; however, condensation

on the specimen shall always be avoided This can be obtained for small specimens by pre-heating them to the chamber temperature

Adjust the temperature in the chamber to the prescribed severity In order to avoid condensation on the specimen, control the specimen temperature or allow the specimen to reach the temperature first and then adjust the humidity in the chamber to the prescribed severity

– 8 – 60068-2-78  IEC:2012 Adjust the humidity to the prescribed severity within a period of time of not more than 2 h Expose the specimen to the test conditions and duration as specified in the relevant specification The duration is measured from the time the specified conditions are achieved The relevant specification shall define the operating conditions and the period (or periods) in which they shall be carried out

After conditioning at the prescribed severity and before the final measurement, the recovery procedure shall be followed

Recovery procedure

4.5

The relevant specification shall prescribe the recovery method and duration Recovery conditions are described in IEC 60068-1

5 Measurements

Initial measurements

5.1

The specimen shall be visually inspected and electrically and mechanically checked, as required by the relevant specification

Intermediate measurements

5.2

The relevant specification may call for measurements during the test procedure while the specimen is still in the chamber If such measurements are required, the relevant specification shall define the measurements and the period (periods) at which they shall be carried out For these measurements, the specimen shall not be removed from the chamber

Final measurements

5.3

The specimen shall be visually inspected and electrically and mechanically checked, as required by the relevant specification

6 Information to be given in the relevant specification

The following details shall be given as far as they are applicable:

a) preconditioning;

b) initial measurements;

c) details of mounting or supports;

d) state of specimen (unpowered, powered, packaged, unpackaged, etc.);

e) type of specimen – heat dissipating or non-heat dissipating;

f) test severities and tolerances

1) temperature,

2) relative humidity,

3) duration;

g) intermediate measurements;

h) recovery conditions;

i) final measurements;

j) any deviation in procedure as agreed upon between customer and supplier

BS EN 60068-2-78:2013

60068-2-78  IEC:2012 – 9 –

7 Information to be given in the test report

As a minimum, the test report shall contain the following information Items shown in parentheses are examples

accreditation – if any)

g) Relevant laboratory test procedure (code and object)

h) Test specimen description (drawing, photo, quantity, build status, etc.)

identification, etc.) j) Performance of test apparatus (set point temperature control, air flow, etc.) k) Uncertainties of measuring system (uncertainties data)

m) Initial, intermediate and final

measurements (initial, intermediate and final measurements)

p) Performance of test specimens (results of functional tests, etc.)

q) Observations during testing and

_

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