1、CENELEC EN*bOOb8-2- bb 94 3404583 0152851 639 W BRITISH STANDARD Environmental testing Part 2. Test methods Test Cx. Damp heat, steady state (unsaturated pressurized vapour) The European Standard EN 60068-2-66 : 1994 has the status of a British Standard This Part should be read in conjunction with B
2、S 2011 : Part 1.1 General and guidance BS EN 1995 1994 60068-2-66 : IEC 68-2-66 : CENELEC ENmbOOb8-2- bb 94 = 3404583 0152852 575 BS EN 60068-2-66 : 1995 under the authority of the Standards Board and comes into Amd. No. Date effect on 15 April 1995 O BSI 1995 The following BSI references relate to
3、the work on this standard: Committee reference GEL50/2 Draft for comment 91/03310 DC ISBN O 680 23681 6 Committees responsible %xt affected The preparation of this British Standard was entrusted by Technical Committee GEL/50, Environmental testing of electrotechnical products, to Subcommittee GEL/50
4、/2, Climatic tests upon which the following bodies were represented : Federation of the Electronics Industry GAMBICA (BEAMA Ltd.) Ministry of Defence Society of Environmental Engineers Society of Motor Manufacturers and Traders Limited The following bodies were also represented in the drafting of th
5、e standard, through subcommittees and panels: Biodeterioration Society Institute of Metals National Supervising Inspectorate (BSI-QA) CENELEC EN*bOOb-2- bb 94 3404583 0152853 401 BS EN 60068-2-66 : 1995 Contents page Committees responsible Inside front cover National foreword ii Foreword 2 Ext of EN
6、 60068-2-66 3 i CENELEC ENMb0068-2- bb 94 3404583 0352854 348 BS EN 6068-2-66 : 1995 National foreword This British Standard has been prepared by Subcommittee GEL502 and is the English language version of EN 60068-2-66 : 1994 Environmental testiw Part 2: lbst methods %t Cx: Damp heat, steady state (
7、unsaturated prmrixed vapour), published by the European Committee for Electrotechnical Standardization (CENELEC). It is identical with IEC 68-2-66 : 1994 published by the International Electrotechnical Commission (IEC). Compliance with a British Standard does not of itself confer immunity from legai
8、 obligations. ii CENELEC EN*bOOb8-2- 66 94 3404583 0352855 284 W EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 60068-2-66 August 1994 ICs 19.040 Descriptors: Environmental testing, electricity, component, equipment, climatic test, damp heat, steady state, unsaturated pressurized vapour, proce
9、dures, components specifications writing, equipment specifications writing English version Environmental testing Part 2: Test methods Test Cx: Damp heat, steady state (unsaturated pressurized vapour) (IEC 68-2-66 : 1994) Essais denvironnement Umweltprf ungen Partie 2: Mthodes dessai Essai Cx: Essai
10、continu de chaleur humide (vapeur pressurise non sature) Teil 2: Prfverfahren Prfung Cx: Feuchte Wrme, konstant (ungesttigter Druckdampf) (CE1 68-2-66 : 1994) (IEC 68-2-66 : 1994) This European Standard was approved by CENELEC on 1994-07-05. CENELEC members are bound to comply with the CENKENELEC In
11、ternal 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
12、 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 status as the official versions. CE
13、NELEC members are the national electrotechnical committees of Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. CENELEC European Committee for Electrotechnical Standardizatio
14、n Comit Europen de Normalisation Electrotechnique Europisches Komitee fr Elektrotechnische Normung Central Secretariat: rue de Stassart 35, B-1050 Brussels O 1994 Copyright reserved to CENELEC members Ref. No. EN 60068-2-66 : 1994 E CENELEC EN*b0068-2- 66 94 3404583 0352856 II0 W Page 2 EN 60068-2-6
15、6 : 1994 Foreword The text of document SOB(C0) 342, as prepared by Subcommittee 50B: Climatic tests, of IEC Technical Committee 50: Environmental testing, was submitted to the IEC-CENELEC parallel vote in February 1994. The reference document was approved by CENELEC as EN 60068-2-66 on 5 July 1994.
16、The following dates were fixed: - latest date of publication of an identical national standard (dop) 1995-07-01 - latest date of withdrawal of conflicting national standards (dow) 1995-07-01 Annexes designated normative are part of the body of the standard. Annexes designated informative are given o
17、niy for information. In this standard, annex A is normative and annexes B, C and D are informative. CONTENTS Page Clause 1 2 3 4 5 6 7 8 9 10 Scope . 4 General description . 4 Description of test apparatus . 4 Severities 5 Initial measurements . 6 Testing 6 Intermediate measurements . 7 Recovery . 7
18、 Final measurements 8 Information to be given in the relevant specification 8 Annexes A Steam table 9 B Physical significance of the test 12 C Determination of humidity . 13 D Test apparatus and handling . 15 CENELEC EN*b00b8-2- 66 94 = 3404583 0152858 T3 m Page 4 EN 60068-2-66: 1994 ENVIRONMENTAL T
19、ESTING - Part 2: Test methods - Test Cx: Damp heat, steady state (unsaturated pressurized vapour) 1 Scope This International Standard provides a standard test procedure for the purpose of evaluating, in an accelerated manner, the resistance of small electrotechnical products, primarily non- hermetic
20、ally sealed components, to the deteriorative effect of damp .heat. The test is not intended to evaluate external effects, such as corrosion and deformation. 2 General description In this test, the specimen is subjected to very high levels of unsaturated damp heat for a relatively short period. Elect
21、rical bias is usually applied. Due to the very accelerated nature of the test, careful consideration must be given to the choice of test conditions, since this may have an important effect on the type of failure mode which could occur (see annex B). The test provides three temperatures at a relative
22、 humidity of 85 %. The test severity is defined by the duration at one of the temperatures. Care shall be taken not to reach the maximum rated temperature of the specimen andlor the critical temperature of any encapsulating materials. The glass transition temperature of a plastic is a typical exampl
23、e of a critical transition temperature. In the case of plastic encapsulated components, degradation results from absorption of water-vapour by the plastic, and penetration of moisture along terminals. 3 Description of test apparatus 3.1 The test chamber The chamber shall be so constructed that: a) i
24、t can produce the temperature and relative humidity given in table 1, and sustain the pressure values given in clause 4, note 3; b) it is capable of providing controlled conditions of temperature, relative humidity and pressure during testing, and the ramp-up to, and ramp-down from, specified test c
25、onditions; c) the temperature and humidity of the chamber can be monitored by means of sens- ing devices located in the working space, and/or other areas giving the same results (e.g. a steam generator). NOTE - The direct measurement of relative humidity during this test is not possible with current
26、 techniques. Guidance on the determination of the relative humidity in the working space is given in annex C. CENELEC EN*b0068-2- 66 94 m 340i1583 0152859 92“ m Temperature “Cl) 110 Page 5 EN 60068-2-66 : 1994 Relative humidity Duration (in hours)3) %*I 1 II III 85 96 192 408 d) the enclosed atmosph
27、ere can be expelled from the chamber by the water-vapour prior to the commencement of testing; e) condensed water is not allowed to fall on the specimen; f) the materials used in the construction shall not cause any corrosion of the spe- cimen, or degradation of the quality of the humidifying water
28、(see clause D.2). 130 The temperature tolerance of f2 OC is intended to take account of absolute errors in the measurement, fluctuations of the chamber temperature at any point, and variations between all points within the working space. 85 24 48 96 However, in order to maintain the relative humidit
29、y within the specified tolerance of f5 Yo, it is necessary to keep the difference between any two points in the working space (at any instant) within narrower limits. The specified humidity tolerance will be exceeded if such temperature differences exceed 1,5 OC. It is also necessary to restrict the
30、 short-term temperature fluctuations due to cycling of the chamber heater to a similar value. The specimen should notsignificantly impede the vapour flow. Condensation shall not be allowed to form on the specimen at any time during the test. 3.2 The humidifying water Distilled or deionised water sha
31、ll be used. The water shall have a resistivity of not less than 0,5 MRcm at 23 OC. The pH value shall be between 6,O and 7.2 at 23 OC. Before the water is placed in the humidifier, all internal parts of the chamber shall be cleaned. Guidance on cleaning is given in clause D.4. 4 Severities One of th
32、e combinations of temperature and duration shown in table 1 shall be used unless otherwise specified in the relevant specification. For each temperature, three durations are defined. Table 1 - Severity CENELEC ENab0068-2- bb 94 D 3404583 Ol1528b0 b4L = Page 6 EN 6068-2-66 : 1994 NOTES 1 It is not re
33、commended that a test should be restarted; however, if. at a given temperature it is required to subject the specimen to a longer duration than that given in column 111 of table 1. then the test shall be recommenced in accordance with the requirements of clause 6. The test shall be recommenced withi
34、n 96 h of the end of the ramp-down period of the previous test. During the interval between the tests, the specimen shall be held under standard atmospheric conditions for meacurement and tests, unless otherwise specified in the relevant specification. 2 the ramp-up and ramp-down period and the cham
35、ber cleaning and preparation time. 3 130 “C respectively. The durations given for testing at the specified conditions do not include the additional time required for The vapour pressures are approximately 0.12 MPa, 0,17 MPa and 0,23 MPa at 1 10 OC, 120 OC and 5. Initial measurements The specimen sha
36、ll be submitted to the visual, dimensional and functional checks pre- scribed by the relevant specification. 6 Testing 6.1 With the chamber and specimen at the laboratory conditions of temperature, pressure and humidity, the specimen shall be installed in the working space in the chamber. 6.2 Positi
37、oning and mounting of the specimen The specimen shall not be subjected to radiant heat from the heaters or the chamber wall. If required by the relevant specification, a specific mounting structure shall be used. The heat conductivity and the thermal capacity of the mounting fixtures shall be low so
38、 that for all practical purposes the specimen is thermally isolated. Care shall be exercised in the choice of mounting structure and mounting fixture materials to minimize the effects of contamination and to minimize degradation due to corrosion and other mechanisms (see clause D.2). 6.3 Bias voltag
39、e If required by the relevant specification, the specimen shall have a bias voltage applied during exposure. Guidance on the application of bias is given in annex D. The bias voltage (or bias voltage cycle) shall be applied to the specimen when the temperature and the relative humidity have reached
40、the stable state, and continue until the specimen is under recovery conditions. CENELEC ENrbOOb8-2- bb 7V W 3VOV583 01528bL 584 Page 7 EN 60068-2-66 : 1994 6.4 The test cycle 6.4.1 The temperature of the chamber shall be raised to the appropriate value. During this period the enclosed atmosphere is
41、expelled from the chamber by the water-vapour, and the temperature and the relative humidity shall not exceed the specified value. Condensed water is not allowed on the specimen at any time during the test cycle. Stabilization of temperature and humidity shall take place within 1,5 h. However, if st
42、abilization takes longer than 1.5 h, the test requirements will be met if stabilization is achieved in not more than 3 h and the specified test duration is greater than 48 h. 6.4.2 The temperature and relative humidity shall be maintained within the prescribed limits for a duration as specified in t
43、he relevant specification. The test duration shall commence as soon as the conditions have stabilized. 6.4.3 At the end of the specified duration, the chamber pressure, temperature and relative humidity shall be restored to standard atmospheric conditions for measurement and tests in not less than 1
44、 h and not more than 4 h. During this period, the temperature and the relative humidity shall not exceed the specified value. The conditions may be achieved by means of natural cooling. If the pressure is reduced by release from the chamber, care shall be taken that the specimen is not subject to ra
45、pid depressurization. The pressure shall not fall below the laboratory pressure. The bias should normally be maintained during this period. 6.4.4 On completion of the cooling period, the specimen shall be subjected to the recovery procedure. 7 Intermedlate measurements The relevant specification may
46、 require electrical and/or mechanical checks during testing. If it is required to make intermediate measurements, the relevant specification shall define the measurements and period(s) during testing after which they shall be carried out. The measurements shall not cause any change to the test condi
47、tions. Measurements preceded by recovery which would require the removal of the specimen from the chamber are not permissible during testing. 8 Recovery Upon completion of testing, the specimen shall be allowed to recover for not less than 2 h and not more than 24 h at standard atmospheric condition
48、s for measurement and tests. CENELEC EN*bOOb8-2- bb 94 m 3404583 Ol1528b2 414 Page 8 EN 60068-2-66 : 1994 9 Final measurements The specimen shall be submitted to the visual, dimensional, and functional checks prescribed by the relevant specification. 10 Information to be given in the relevant specif
49、ication When this test is included in a relevant specification, the following details shall be given, in as far as they are applicable. The relevant specification shall supply the information as required in the clauses listed below, paying particular attention to the items marked with an asterisk (*), as this information is always required. Clause a) Test severity 4 6) initiai measurements 5 c) Specific mounting structures . 6 d) Bias voltage 6 e) Intermediate measurements . 7 f) Final measurements* 9 CENELEC EN*b0068-2- 66 9Y W 340Y583 0352863 350 W Page 9 EN 60
