1、 INTERNATIONAL STANDARD IECCEINORME INTERNATIONALE60068-2-2Fifth editionCinquime dition2007-07Environmental testing Part 2-2: Tests Test B: Dry heat Essais denvironnement Partie 2-2: Essais Essai B: Chaleur sche Reference number Numro de rfrence IEC/CEI 60068-2-2:2007 BASIC SAFETY PUBLICATION PUBLIC
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14、ervice clients ou contactez-nous: Email: csciec.ch Tl.: +41 22 919 02 11 Fax: +41 22 919 03 00 INTERNATIONAL STANDARD IECCEINORME INTERNATIONALE60068-2-2Fifth editionCinquime dition2007-07Environmental testing Part 2-2: Tests Test B: Dry heat Essais denvironnement Partie 2-2: Essais Essai B: Chaleur
15、 sche N Commission Electrotechnique InternationaleInternational Electrotechnical Commission PRICE CODE CODE PRIX For price, see current cataloguePour prix, voir catalogue en vigueur BASIC SAFETY PUBLICATION PUBLICATION FONDAMENTALE DE SCURIT 2 60068-2-2 IEC:2007 CONTENTS FOREWORD.4 INTRODUCTION.6 1
16、Scope.7 2 Normative references .7 3 Terms and definitions .8 4 Application of tests for non heat-dissipating specimens versus tests for heat-dissipating specimens 8 4.1 General .8 4.2 Ascertaining high or low air velocity in the test chamber8 4.3 Application of tests with sudden change of temperatur
17、e versus tests with gradual change of temperature9 4.4 Testing of heat-dissipating specimens .9 4.5 Temperature monitoring 9 4.6 Packaging .9 4.7 Diagrammatic representations .9 5 Test descriptions 10 5.1 General .10 5.2 Test Bb: Dry heat for non heat-dissipating specimens with gradual change of tem
18、perature.10 5.2.1 Object .10 5.2.2 General description .11 5.3 Test Bd: Dry heat for heat-dissipating specimens with gradual change of temperature that are not powered during the conditioning period.11 5.3.1 Object .11 5.3.2 General description .11 5.3.3 Energising the specimen .11 5.4 Test Be: Dry
19、heat for heat-dissipating specimens with gradual change of temperature that are required to be powered throughout the test.11 5.4.1 Object .11 5.4.2 General description .12 6 Test procedure .12 6.1 Confirmation of performance .12 6.2 Working space 12 6.3 Thermal radiation 12 6.4 Mounting .13 6.5 Sev
20、erities 13 6.5.1 General .13 6.5.2 Temperature13 6.5.3 Duration 13 6.6 Preconditioning .13 6.7 Initial measurements .13 6.8 Conditioning 13 6.8.1 Steady state conditions .13 6.8.2 Absolute humidity 14 6.9 Intermediate measurements 14 6.10 Final temperature ramp .14 60068-2-2 IEC:2007 3 6.11 Recovery
21、.14 6.12 Specimen with artificial cooling14 6.13 Final measurements 14 7 Information to be given in the relevant specification .15 8 Information to be given in the test report 15 Figure 1 Block diagram Tests B: Dry Heat10 4 60068-2-2 IEC:2007 INTERNATIONAL ELECTROTECHNICAL COMMISSION _ ENVIRONMENTAL
22、 TESTING Part 2-2: Tests Test B: Dry heat FOREWORD 1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising all national electrotechnical committees (IEC National Committees). The object of IEC is to promote international co-operation on all q
23、uestions concerning standardization in the electrical and electronic fields. To this end and in addition to other activities, IEC publishes International Standards, Technical Specifications, Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC Publicat
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29、 responsible for any equipment declared to be in conformity with an IEC Publication. 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 t
30、echnical committees and IEC National 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
31、IEC Publications. 8) Attention is drawn 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 su
32、bject of patent rights. IEC shall not be held responsible for identifying any or all such patent rights. International Standard IEC 60068-2-2 has been prepared by IEC technical committee 104: Environmental conditions, classification and methods of test. This fifth edition of IEC 60068-2-2 cancels an
33、d replaces the fourth edition issued in 1974. It includes the revised text of the fourth edition, amendment 1 issued in 1993 and amendment 2 issued in 1994. It has the status of a basic safety publication in accordance with IEC Guide 104. The main changes from the previous edition are as follows: Te
34、sts Ba and Bc have been deleted since they were more severe tests than Test Nb, IEC 60068-2-14: Change of temperature. Secondly it was considered justified to delete the 3 % value on the temperature difference between the chamber air and the wall temperatures. Thirdly it is proposed that the test sp
35、ecimen be powered throughout the test where required; and, finally, the annexes have been removed. 60068-2-2 IEC:2007 5 The text of this standard is based on the following documents: FDIS Report on voting 104/412/FDIS 104/430/RVD Full information on the voting for the approval of this standard can b
36、e found in the report on voting indicated in the above table. This standard has been drafted in accordance with the ISO/IEC Directives, Part 2. A list of all the parts of the IEC 60068 series, under the general title Environmental testing, can be found on the IEC website. The committee has decided t
37、hat the contents of this publication will remain unchanged until the maintenance result date indicated on the IEC web site under “http:/webstore.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 am
38、ended. 6 60068-2-2 IEC:2007 INTRODUCTION RELATIONSHIP OF SUFFIXES BETWEEN TESTS A: COLD, AND TESTS B: DRY HEAT The relationship of suffixes between Tests A: Cold, and Tests B: Dry heat, is shown in the following table: Tests A: Cold Tests B: Dry heat Suffix letter Specimen type Temperature change Ai
39、r velocity Specimen type Temperature change Air velocity a Withdrawn Withdrawn b Non heat Gradual High preferred Non heat Gradual High preferred c Withdrawn Withdrawn d Heat dissipating Gradual Low preferred Heat Gradual Low preferred e Heat dissipating powered throughout Gradual Low preferred Heat,
40、 powered throughout Gradual Low preferred 60068-2-2 IEC:2007 7 ENVIRONMENTAL TESTING Part 2-2: Tests Test B: Dry heat 1 Scope This standard deals with dry heat tests applicable both to heat-dissipating and non heat-dissipating specimens. For non heat-dissipating specimens, Tests Bb and Bd do not dev
41、iate essentially from earlier issues. The object of the dry heat test is limited to the determination of the ability of components, equipment or other articles to be used, transported or stored at high temperature. These dry heat tests do not enable the ability of specimens to withstand or operate d
42、uring the temperature variations to be assessed. In this case, it would be necessary to use IEC 60068-2-14 Test N: Change of temperature. The dry heat tests are subdivided as follows: Dry heat test for non heat-dissipating specimens with gradual change of temperature, Bb. Dry heat tests for heat-dis
43、sipating specimens with gradual change of temperature, Bd; with gradual change of temperature, specimen powered throughout, Be. The procedures given in this standard are normally intended for specimens that achieve temperature stability during the performance of the test procedure. 2 Normative refer
44、ences IEC 60068-1:1988, Environmental testing Part 1: General and guidance IEC 60068-3-1, Environmental testing Part 3: Background information Section one: Cold and dry heat tests IEC 60068-3-5, Environmental testing Part 3-5: Supporting documentation and guidance Confirmation of the performance of
45、temperature chambers IEC 60068-3-7, Environmental testing Part 3-7: Supporting documentation and guidance Measurements in temperature chambers for tests A and B (with load) IEC 60068-5-2, Environmental testing Part 5-2: Guide to drafting of test methods Terms and definitions IEC 60721 (all parts), C
46、lassification of environmental conditions 8 60068-2-2 IEC:2007 3 Terms and definitions For the purposes of this document, the definitions in IEC 60068-5-2 and the following definitions apply. 3.1 low air velocity in the working space the velocity of conditioning airflow within a working space which
47、is sufficient to maintain conditions but low enough so that the temperature at any point on the test specimen is not reduced by more than 5 K by the influence of the circulation of the air (if possible, not more than 0,5 m/s) 3.2 high air velocity in the working space the velocity of conditioning ai
48、rflow within a working space, which, in order to maintain conditions, also reduces the temperature at any point on the test specimen by more than 5 K by the influence of the circulation of the air 4 Application of tests for non heat-dissipating specimens versus tests for heat-dissipating specimens 4
49、.1 General The temperature chamber(s) shall be constructed and verified in accordance with specifications IEC 60068-3-5 and IEC 60068-3-7. Further guidance for the dry heat and cold tests can be found in IEC 60068-3-1, and general guidance in IEC 60068-1. A specimen is considered heat-dissipating only if the hottest point on its surface, measured in f
