1、BRITISH STANDARD Environmental testing - Part 2: Tests - Test Z/ANI: Combined cold/ow air pressure tests The European Standam British Standard EN 60068 401999 has the status of a ICs 19.040 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW BS EN 60068-2-40:2000 EC i0068-2-40:197
2、6 STDoBSI BS EN bOOb-2-YO-ENGL 2000 m LbZrlbb9 08352Y2 8T5 m BS EN 60068-2-402000 been prepared under the direction of the Electrotechnical Sector Committee, was published under the authority of the Standards Committee and comes into effect on 15 April 2000 Amd. No. 0 BSI 4-2ooO ISBN O 580 34051 1 N
3、ational foreword Da Comments This British Standard is the official Engsh language version of EN 60068-2-40 1999. It BS 2011-2.1z/AM:1977 which is withdrawn. The UK participation in its preparation was entrusted to Technical Committee GEY104, Environmental conditions, classification and testing, whic
4、h has the responsibility to: is identical with IEC 60068-2-40: 1976 plus amendment 1: 1983. It supersedes - aid enquirem to understand the text; - present to the responsible internationalEuropean committee any enquiries on the interpretation, or proposals for change, and keep the UK interests inform
5、ed; - monitor related international and European developments and promulgate them in the UK A list of organizations represented on this committee can be obtained on request to its %crew. Flom 1 January 1997, all IEC publications have the number 60000 added to the old number. For instance, IEC 27-1 h
6、as been renumbered as IEC 60027-1. For a period of time during the change over from one numbering system to the other, publications may contain identiers from both system. Cross-references Attention is drawn to the fact that CEN and CENELEC standards normally include an annex which lists nonnative r
7、eferences to international publications with their correspondmg European publications. The British Standards which implement these international or European publications may be found in the BSI Standards Catalogue under the section entitled “International Standards Correspondence Index“, or by using
8、 the “Find“ facility of the BSI Standards Electronic Catalogue. A British standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity f
9、rom legal obligations. Summary of pages This document comprises a front cover, an inside front cover, the EN title page, pages 2 to 11 and a back cover. The BSI copynght notice displayed in this document indicates when the document was last issued. EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM E
10、N 60068-2-40 November 1999 ICs 19.040 Supersedes HD 323.2.40 S1:1988 English version Environmental testing Part 2: Tests - Test Z/AM: Combined coldllow air pressure tests (IEC 60068-2-40: 1976 + AI : 1983) Essais denvironnement Umweltprfungen Partie 2: Essais - Essai Z/AM: Essais combins froid/basse
11、 pression atmosphrique Luftdruck Teil 2: Prfungen - Prfung Z/AM: Kombinierte Prfung - Klte/Niedriger (CE1 60068-2-40: 7 976 + Al 1983) (IEC 60068-2-40: 1 976 + A 1 1 983) This European Standard was approved by CENELEC on 1999-1 0-01. CENELEC members are bound to comply with the CENICENELEC Internal
12、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 Central Secretariat or to any CENELEC member
13、. 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 status as the official versions. CENELEC m
14、embers are the national electrotechnical committees of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. CENELEC European Committee for Electrotechnical Stand
15、ardization Comit Europen de Normalisation Electrotechnique Europisches Komitee fr Elektrotechnische Normung Central Secretariat: rue de Stassari 35, B - 1050 Brussels 1999 CENELEC - Ali rights of exploitation in any form and by any means reserved worldwide for CENELEC members. Ref. No, EN 60068-2-40
16、:1999 E STDoBSI BS EN b0068-2-VO-ENGL 2000 = Lb24bb7 0835244 678 Page 2 EN 60068-2-40: 1 999 Foreword The text of the International Standard IEC 60068-2-40: 1 976 and its amendment 1 : 1 983, prepared by IEC TC 50 (transformed into IEC TC 104 “Environmental conditions, classification and methods of
17、test“), was approved by CENELEC as HD 323.2.40 SI on 1988-03-01. This Harmonization Document was submitted to the formal vote for conversion into a European Standard and was approved by CENELEC as EN 60068-2-40 on 1999-1 0-01. The following date was fixed: - latest date by which the EN has to be imp
18、lemented at national level by publication of an identical national standard or by endorsement (dp) 2000- 1 0-0 1 Annexes designated “normative“ are part of the body of the standard. In this standard, annex ZA is normative. Annex ZA has been added by CENELEC. Endorsement notice The text of the Intern
19、ational Standard IEC 60068-2-40: 1 976 and its amendment 1 : 1 983 was approved by CENELEC as a European Standard without any modification. . STD-BSI BS EN bOObA-2-40-ENGL 2000 Lb24bb 0835245 504 = Page 3 EN 60068-2-40:1999 CONTENTS Clause Introduction . 1 . 1 General . 1.2 Low air pressure . 1.3 Te
20、mperature . 1.4 Related documents Object . General description Description of test apparatus “ 4.1 Test chamber . 4.2 Mounting . Severities 5.1 General . 5.2 Preconditioning . Initial measurements ._. Conditioning 8.1 General . 8.2 Procedure for heat-dissipating specimen without artificial cooling o
21、f the specimen and for non-heat-dissipating specimen . 8.3 Precautions when testing specimens with artificial cooling . Intermediate measurements . Preferred combinations of temperature, air pressure and duration . 10 Recovery . 11 Final measurements . 12 Information to be given in the relevant spec
22、ification Figures . Annex ZA(normative) Normative references to international publications with corresponding European publications Page 4 4 4 4 4 5 5 5 5 5 5 5 6 6 6 6 6 6 7 8 8 8 8 9 their 11 OBSI 04-2000 STD-BSI BS EN 60068-2-40-ENGL 2000 = I1624669 083524b 440 Page 4 EN 60068-2-40: 1999 BASIC EN
23、VIRONMENTAL TESTING PROCEDURES - Part 2: Tests - Test Z/AM: Combined coldllow air pressure tests 1 Introduction 1.1 General This publication deals with combined cold (with gradual (or rapid) change of temperature) and low air pressure tests for both heat-dissipating and non-heat-dissipating specimen
24、s. (see Sub-clauses 8.2.2 and 8.2.8). The object of the test is to determine the ability of components or equipment or other articles to be stored and used under a simultaneous combination of low temperature and low air pressure. This combined test should normally be used only if the effects of comb
25、ined environments will not be revealed by subjecting the specimen to single environments. The procedures given in this publication are limited to the case of specimens which achieve temperature stability during the test procedure. In the case of testing heat-dissipating specimens, this procedure app
26、lies only to the testing of one specimen at a time. 1.2 Low air pressure The test procedure applies to air pressure down to about 10 mbar. At air pressures below 10 rnbar, phenomena not taken into account in the design of this test procedure become important. The relationship between altitude, press
27、ure and temperature has not been indicated in this publication. Such data should be obtained from special publications. 1.3 Temperature I .3.1 non-heat-dissipating specimens versus tests for heat-dissipating specimens shall apply. The guidance given in the introduction to IEC 60068-2-1 for the appli
28、cation of tests for NOTE - Non-heat-dissipating specimens are defined as in clause 4 of IEC 60068-1. The measurement of hottest spot temperature must not be made at low pressure. 1.3.2 Heat-dissipating specimens should preferably be tested with no forced air circulation as for Tests A: Cold. 1.4 Rel
29、ated documents IEC 60068: IEC 60068-1: Part 1: General. IEC 60068-2-1: IEC 60068-2-13: Part 2: Tests - Test M: Low air pressure IEC 60068-3-1: IEC 60068-3-2: Basic environmental testing procedure. Part 2: Tests - Tests A: Cold. Part 3: Background information - Section One: Cold and dry heat tests. P
30、art 3: Background information - Section Two: Combined temperature/ low air pressure tests. OBSI 04-2000 STD.BSI BS EN 60068-2-40-ENGL 2000 lb24bb 0835247 387 m Page 5 EN 60068-2-40: 1999 2 Object To provide a standard test procedure to determine the suitability of components, equipments or other art
31、icles for use andlor storage under a combination of low temperature and low air pressure. 3 General description This test is a combination of Test Ab or Ad: Cold, and Test M: Low air pressure. The specimen is first subjected to the appropriate severity of cold as indicated in the relevant specificat
32、ion. In the case of operational tests, a check is then made to ensure that the specimen is capable of operation. With the temperature maintained at the indicated value, the chamber air pressure is then reduced to the appropriate severity as specified in the relevant specification. These conditions a
33、re maintained for the specified duration. Test profiles illustrating the procedure are shown in figure 1 a and figure 1 b. 4 Description of test apparatus 4.1 Test chamber The chamber shall be capable of maintaining the conditions specified for Test Ab (for non- heat-dissipating specimen) or Test Ad
34、 (for heat-dissipating specimen) and for Test M. The requirement for the chamber wall temperature does not apply during periods of temperature or pressure change. Care shall be taken to avoid air contamination by ancillary equipment and devices and by the air introduced when pressure is restored to
35、normal. 4.2 Mounting For the testing of a heat-dissipating specimen, the mounting of the test specimen shall comply with the requirements for Test Ad. 5 Severities 5.1 General The severities, as indicated by temperature, air pressure and duration of exposure, shall be specified in the relevant speci
36、fication. The temperature and low air pressure values, tolerances and durations shall comply with those given in Tests Ab or Ad and M. NOTE - It is appreciated that at air pressures below 100 mbar. the tolerances given in Test A might be difficult to attain. Wider tolerances may in this case be pres
37、cribed by the relevant specification. The duration of exposure shall be measured from the time when temperature stability of the specimen has been reached under conditions of low air pressure (see figures 1 a and 1 b). OBS104-2000 STDWBSI BS EN bOOb-2-40-ENGL 2000 E 1b24bb9 0835248 213 m Page 6 5.2
38、Preferred combinations of temperature, air pressure and duration EN 60068-2-40:1999 I I Temperatu re Air pressure Duration - llll“ (Hl . 1 i 2 (OC) (kW (mbar) -55 -55 15 2 2 . . 2; 16 2; 16 2; 16 -55 40 -40 55 -25 55 550 -40 70 700 .- -_II 6 Preconditioning The relevant specification may call for pr
39、econditioning. 7 Initial measurements The specimen shall be visually inspected and electrically and mechanically checked as required by the relevant specification. 8 Conditioning 8.1 General Heat-dissipating specimens These shall preferably be tested without forced air circulation in the chamber acc
40、ording to Test Ad. When the chamber used for testing is large enough to meet the conditions specified for Test Ad, but cooling of the chamber can only be carried out by forced air circulation, Method A of Test Ad may be applied. Non-heat-dissipating specimens These may be tested in a chamber with or
41、 without forced air circulation. 8.2 Procedure for heat-dissipating specimen without artificial cooling of the specimen and for non-heat-dissipating specimen 8.2.1 The chamber shall be at the temperature of the laboratory. The specimen at the ambient temperature of the laboratory shall be introduced
42、 into the chamber in the unpacked, switched-off, “ready-for-use“ state, in its normal position or as otherwise specified. OBSI 04-2000 Page 7 EN 60068-2-40:1999 8.2.2 The temperature within the chamber shall be adjusted to the temperature appropriate to the severity. The specimen shall be allowed to
43、 reach temperature stability. The rate of change of temperature within the chamber shall not exceed 1 “C per minute, averaged over a period of not more than 5 minutes. The test (ambient) temperature shall be measured as in 4.4.2 of IEC 60068-1. Note. - The maximum rate of change of temperature of 1
44、“Clmin does not apply to specimens which are capable of withstanding thermal shock, e.g. specimens which are normally capable of withstanding rapid change of temperature Tests Na or Nc. 8.2.3 For operational tests only: The specimen shall be switched on and checked to ascertain whether it is capable
45、 of functioning in accordance with the relevant specification. The specimen shall then be switched off and allowed to reach temperature stability. The relevant specification may require another procedure for the check at low temperature and normal air pressure. 8.2.4 The pressure within the chamber
46、shall then be reduced to the value appropriate to the severity. The rate of change of pressure shall not exceed 100 mbar per minute. 8.2.5 For operational tests only: The specimens shall be switched on or be electrically loaded. Checks shall be made to ascertain whether the specimen is capable of fu
47、nctioning in accordance with the relevant specification. The specimens may remain in the operating condition or be switched off as prescribed by the relevant specification. If required by the relevant specification, intermediate measurements shall be performed in accordance with Clause 9. 8.2.6 The
48、conditions of temperature and pressure shall be maintained for the specified duration. 8.2.7 For operational tests only: Intermediate measurements shall be performed during the final hour of the low pressure period in accordance with the relevant specification. The specimens shall be switched off or
49、 unloaded before the air pressure is restored. OBSI 04-2000 STD-BSI BS EN bOOb-2-4O-ENGL 2000 m Lb24bb 0835250 971 = Page 8 8.2.8 The chamber pressure shall be restored to normal at a rate not exceeding 100 mbar per minute. During the increase of pressure, temperature control is not required. The specimen shall remain in the chamber and the temperature shall be gradually raised to a value lying within the limits of standard atmospheric conditions for testing. The rate of change of the temperature within the chamber shall not exceed 1C per minute
copyright@ 2008-2019 麦多课文库（www.mydoc123.com）网站版权所有
备案/许可证编号：苏ICP备17064731号-1