1、 S+ IEC 60068-2-78 Edition 2.0 2012-10 IEC STANDARDS+ Environmental testing Part 2-78: Tests Test Cab: Damp heat, steady state Essais denvironnement Partie 2-78: Essais Essai Cab: Chaleur humide, essai continu S+ IEC 60068-2-78:2012 BASIC SAFETY PUBLICATION PUBLICATION FONDAMENTALE DE SCURIT colour
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19、Cab: Chaleur humide, essai continu IEC 60068-2-78:2012 BASIC SAFETY PUBLICATION PUBLICATION FONDAMENTALE DE SCURIT 2 60068-2-78 IEC:2012 CONTENTS FOREWORD . 3 INTRODUCTION . 5 1 Scope and object 6 2 Normative references . 6 3 Terms and definitions . 6 4 General test procedure . 6 Test chamber and me
20、asuring system 6 4.1Severity . 7 4.2Pre-conditioning 7 4.3Testing procedure . 7 4.4Recovery procedure 8 4.5 5 Measurements 8 Initial measurements . 8 5.1Intermediate measurements 8 5.2Final measurements 8 5.3 6 Information to be given in the relevant specification 8 7 Information to be given in the
21、test report 9 Table 1 Temperature and relative humidity 7 60068-2-78 IEC:2012 3 INTERNATIONAL ELECTROTECHNICAL COMMISSION _ ENVIRONMENTAL TESTING Part 2-78: Tests Test Cab: Damp heat, steady state FOREWORD 1) The International Electrotechnical Commission (IEC) is a worldwide organization for standar
22、dization comprising all national electrotechnical committees (IEC National Committees). The object of IEC is to promote international co-operation on all questions concerning standardization in the electrical and electronic fields. To this end and in addition to other activities, IEC publishes Inter
23、national Standards, Technical Specifications, Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested in the subject dealt with may participate
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26、ave the form of recommendations for international use and are accepted by IEC National Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any mi
27、sinterpretation by any end user. 4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications transparently to the maximum extent possible in their national and regional publications. Any divergence between any IEC Publication and the corresponding nat
28、ional or regional publication shall be clearly indicated in the latter. 5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any services
29、 carried out by independent certification bodies. 6) All users should ensure that they have the latest edition of this publication. 7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and members of its technical committees and IEC Nationa
30、l Committees for any personal injury, property damage or other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC Publications. 8) Attention is d
31、rawn to the Normative references cited in this publication. Use of the referenced publications is indispensable for the correct application of this publication. 9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of patent rights. IEC shall n
32、ot be held responsible for identifying any or all such patent rights. International Standard IEC 60068-2-78 has been prepared by technical committee 104: Environmental conditions, classification, and methods of test. This second edition cancels and replaced the first edition, published in 2001 and c
33、onstitutes a technical revision. This edition includes editorial and format changes with respect to the previous edition: The test chamber from IEC 60068-3-6 has been introduced. 4 60068-2-78 IEC:2012 The text of this standard is based on the following documents: FDIS Report on voting 104/582/FDIS 1
34、04/588/RVD Full information on the voting for the approval of this standard can be found in the report on voting indicated in the above table. This publication has been drafted in accordance with the ISO/IEC Directives, Part 2. It has the status of a basic safety publication in accordance with IEC G
35、uide 104. A list of all the parts in the IEC 60068 series, under the general title Environmental testing, can be found on the IEC website. The committee has decided that the contents of this publication will remain unchanged until the stability date indicated on the IEC web site under “http:/webstor
36、e.iec.ch“ in the data related to the specific publication. At this date, the publication will be reconfirmed, withdrawn, replaced by a revised edition, or amended. 60068-2-78 IEC:2012 5 INTRODUCTION This part of IEC 60068 provides a test method of high humidity at constant temperature without conden
37、sation 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
38、 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 o
39、n 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
40、 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, Environme
41、ntal 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
42、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 a
43、nd 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
44、chamber can fall on the specimen(s), 60068-2-78 IEC:2012 7 water utilized to maintain humidity levels has electrical conductivity of not more than 20 S/cm, the specimen under test shall not be subjected to radiant heat from the chamber conditioning devices, injected moisture, when applicable, is inj
45、ected 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, un
46、less 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 followin
47、g: Table 1 Temperature and relative humidity Temperature C Relative humidity % RH 30 2 93 3 30 2 85 3 40 2 93 3 40 2 85 3 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
48、 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.
49、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 re
