1、 g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44g54g54g44g50g49g3g40g59g38g40g51g55g3g36g54g3g51g40g53g48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58The European Standard EN 60068-2-2:2007 has the status of a British StandardICS 19.040Environmental
2、 testing Part 2-2: Tests Test B: Dry heatBRITISH STANDARDBS EN 60068-2-2:2007BS EN 60068-2-2:2007This British Standard was published under the authority of the Standards Policy and Strategy Committee on 31 October 2007 BSI 2007ISBN 978 0 580 53468 3Amendments issued since publicationAmd. No. Date Co
3、mmentsThis publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application.Compliance with a British Standard cannot confer immunity from legal obligations. National forewordThis British Standard is the UK implementation of EN 600
4、68-2-2:2007. It is identical to IEC 60068-2-2:2007. It supersedes BS EN 60068-2.2:1993 which is withdrawn.The UK participation in its preparation was entrusted to Technical Committee GEL/104, Environmental conditions, classification and testing.A list of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 c
5、an be obtained on request to its secretary.EUROPEAN STANDARD EN 60068-2-2 NORME EUROPENNE EUROPISCHE NORM September 2007 CENELEC European Committee for Electrotechnical Standardization Comit Europen de Normalisation Electrotechnique Europisches Komitee fr Elektrotechnische Normung Central Secretaria
6、t: rue de Stassart 35, B - 1050 Brussels 2007 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members. Ref. No. EN 60068-2-2:2007 E ICS 19.040 Supersedes EN 60068-2-2:1993 + A1:1993 + A2:1994English version Environmental testing - Part 2-2: Tests - Te
7、st B: Dry heat (IEC 60068-2-2:2007) Essais denvironnement - Partie 2-2: Essais - Essai B: Chaleur sche (CEI 60068-2-2:2007) Umgebungseinflsse - Teil 2-2: Prfverfahren - Prfung B: Trockene Wrme (IEC 60068-2-2:2007) This European Standard was approved by CENELEC on 2007-09-01. CENELEC members are boun
8、d 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 Ce
9、ntral Secretariat 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 Central Secretariat has the same
10、status as the official versions. CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Cyprus, the Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the Netherlands, Norway
11、, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. EN 60068-2-2:2007 2 Foreword The text of document 104/412/FDIS, future edition 5 of IEC 60068-2-2, prepared by IEC TC 104, Environmental conditions, classification and methods of test, was submitted t
12、o the IEC-CENELEC parallel vote and was approved by CENELEC as EN 60068-2-2 on 2007-09-01. This European Standard supersedes EN 60068-2-2:1993 + A1:1993 + A2:1994. The main changes from EN 60068-2-2:1993 + A1:1993 + A2:1994 are as follows: Tests Ba and Bc have been deleted since they were more sever
13、e tests than Test Nb, EN 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 specimen be powered throughout the test where required; and,
14、finally, the annexes have been removed. The following dates were fixed: latest date by which the EN has to be implemented at national level by publication of an identical national standard or by endorsement (dop) 2008-06-01 latest date by which the national standards conflicting with the EN have to
15、be withdrawn (dow) 2010-09-01 Annex ZA has been added by CENELEC. _ Endorsement notice The text of the International Standard IEC 60068-2-2:2007 was approved by CENELEC as a European Standard without any modification. _ 3 EN 60068-2-2:2007 CONTENTS INTRODUCTION.5 1 Scope 6 2 Normative references .6
16、3 Terms and definitions .7 4 Application of tests for non heat-dissipating specimens versus tests for heat-dissipating specimens.7 4.1 General .7 4.2 Ascertaining high or low air velocity in the test chamber .7 4.3 Application of tests with sudden change of temperature versus tests with gradual chan
17、ge of temperature 8 4.4 Testing of heat-dissipating specimens8 4.5 Temperature monitoring.8 4.6 Packaging .8 4.7 Diagrammatic representations8 5 Test descriptions 9 5.1 General .9 5.2 Test Bb: Dry heat for non heat-dissipating specimens with gradual change of temperature.9 5.2.1 Object9 5.2.2 Genera
18、l description10 5.3 Test Bd: Dry heat for heat-dissipating specimens with gradual change of temperature that are not powered during the conditioning period 10 5.3.1 Object10 5.3.2 General description10 5.3.3 Energising the specimen 10 5.4 Test Be: Dry heat for heat-dissipating specimens with gradual
19、 change of temperature that are required to be powered throughout the test 10 5.4.1 Object10 5.4.2 General description11 6 Test procedure .11 6.1 Confirmation of performance11 6.2 Working space.11 6.3 Thermal radiation 11 6.4 Mounting .12 6.5 Severities 12 6.5.1 General .12 6.5.2 Temperature 12 6.5.
20、3 Duration.12 6.6 Preconditioning12 6.7 Initial measurements12 6.8 Conditioning 12 6.8.1 Steady state conditions 12 6.8.2 Absolute humidity 13 6.9 Intermediate measurements.13 6.10 Final temperature ramp13 6.11 Recovery.13 EN 60068-2-2:2007 4 6.12 Specimen with artificial cooling 13 6.13 Final measu
21、rements 13 7 Information to be given in the relevant specification.14 8 Information to be given in the test report .14 Figure 1 Block diagram Tests B: Dry Heat 9 Annex ZA (normative) Normative references to international publications with their corresponding European publications15 5 EN 60068-2-2:20
22、07 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 Air velocity Specimen type
23、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, powered throughout Gradu
24、al Low preferred EN 60068-2-2:2007 6 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 deviate essentially from earl
25、ier 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 during the temperature vari
26、ations 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-dissipating specimens with gr
27、adual 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 references IEC 60068-1:1988, En
28、vironmental 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 temperature chambers IEC 6
29、0068-3-7, 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), Classification of environme
30、ntal conditions 7 EN 60068-2-2:2007 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 is sufficient to maintain c
31、onditions 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 airflow within a working spac
32、e, 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 4.1 General The temperature
33、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
34、its surface, measured in free air conditions (i.e. low air velocity circulation), is more than 5 K above the ambient temperature of the surrounding atmosphere after temperature stability has been reached (see 4.8 of IEC 60068-1). When the relevant specification calls for a storage or transportation
35、test or does not specify an applied load during the test, the Dry Heat Test Bb will apply. 4.2 Ascertaining high or low air velocity in the test chamber Under standard atmospheric conditions for measurements and test (see IEC 60068-1) with an air velocity 0,2 m/s, the specimen shall be switched on o
36、r electrically loaded as specified for the high temperature at which the test is to be carried out. When temperature stability of the specimen has been reached, the temperature of a number of representative points around or on the specimen shall be measured using a suitable monitoring device. The te
37、mperature rise that occurs at each point shall then be noted. The chamber air flow is switched on and, once temperature stability has been achieved, the temperature of the representative points shall again be measured. If the temperatures differ from those measured without air flow by more than 5 K
38、(or a value stated by the relevant specification) this value shall be noted in the test report and the test chamber is considered to have high velocity circulation. The specimen is then switched off and any loading conditions removed. EN 60068-2-2:2007 8 4.3 Application of tests with sudden change o
39、f temperature versus tests with gradual change of temperature In Tests Bb, Bd and Be with gradual change of temperature, the specimen is introduced into the test chamber, the latter being at the laboratory temperature. The temperature in the chamber is then increased gradually so as to cause no detr
40、imental effects on the test specimen due to the temperature change. 4.4 Testing of heat-dissipating specimens Tests Bd and Be describe procedures for testing heat-dissipating specimens with low air velocity circulation. This is to allow localised hot spots to develop within the specimen similar to t
41、hose that would appear in installed applications. 4.5 Temperature monitoring The air temperature in the chamber shall be measured by temperature sensors located at such a distance from the specimen that the effect of the dissipation is negligible. Suitable precautions should be taken to avoid heat r
42、adiation affecting these measurements. For more information see IEC 60068-3-5. 4.6 Packaging For storage and transportation tests, equipment may be tested with its packaging in place. However, as these tests are steady state tests the equipment will eventually stabilise at chambers temperature. Pack
43、aging shall be removed unless the relevant specification requires it to remain in place or heating elements are incorporated in the package. 4.7 Diagrammatic representations To facilitate the choice of test method, a diagrammatic representation of the various procedures is given in Figure 1. 9 EN 60
44、068-2-2:2007 Heat Dissipating? Test BeSee Clause 5.4Test BdSee Clause 5.3Test Bb See Clause 5.2Tests B: Dry HeatPowered during conditioning period?NoNoYes Yes IEC 1181/07 Figure 1 Block diagram Tests B: Dry Heat 5 Test descriptions 5.1 General Tests Bb, Bd, and Be are similar. Differences are noted
45、in Subclauses 5.2.2, 5.3.2 and 5.4.2. All other portions of the tests are the same, starting with Clause 6. The rate of change of temperature within the chamber shall not exceed 1 K per minute, averaged over a period of not more than 5 min. The relevant specification shall define the functioning of
46、the specimen under test. Care shall be taken that any cooling devices of the specimen are in accordance with the prescription in the relevant specification. 5.2 Test Bb: Dry heat for non heat-dissipating specimens with gradual change of temperature 5.2.1 Object This procedure is for non heat-dissipa
47、ting specimens which are subjected to an elevated temperature for a time long enough for the specimen to achieve temperature stability. EN 60068-2-2:2007 10 5.2.2 General description The specimen is introduced into the chamber, which is at the temperature of the laboratory. The temperature is then a
48、djusted to the temperature appropriate to the degree of severity as specified in the relevant specification. After temperature stability of the test specimen has been reached, the specimen is exposed to these conditions for the specified duration. For specimens that are required to be operational (e
49、ven though they do not meet the requirements of being heat dissipating) power shall then be applied to the specimen and a functional test is performed as necessary. A further period of stabilization may be necessary and the specimen shall then be exposed to the high temperature conditions for a duration as specified in the relevant specification. Specimens under test are normally in non-operating conditions. High air velocity circulation is normal
