1、BRITISH STANDARD BS EN 60068-2-66: 1995 IEC 68-2-66: 1994 Environmental testing Part 2: Test methods Test Cx. Damp heat, steady state (unsaturated pressurized vapour) The European Standard EN60068-2-66:1994 has the status of a BritishStandard This Part should be read in conjunction with BS2011-1.1 G
2、eneral and guidanceBSEN 60068-2-66:1995 This British Standard, having been prepared under the direction of the Electrotechnical Sector Board, was published underthe authority of the Standards Board and comes intoeffect on 15 April1995 BSI 05-1999 The following BSI references relate to the work on th
3、is standard: Committee reference GEL/50/2 Draft for comment 91/03310 DC ISBN 0 580 23581 5 Committees responsible The preparation of this British Standard was entrusted by Technical Committee GEL/50, Environmental testing of electrotechnical products, to Subcommittee GEL/50/2, Climatic tests upon wh
4、ich 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 the standard, through subcomm
5、ittees and panels: Biodeterioration Society Institute of Metals National Supervising Inspectorate (BSI-QA) Amendments issued since publication Amd. No. Date CommentsBSEN60068-2-66:1995 BSI 05-1999 i Contents Page Committees responsible Inside front cover National foreword ii Foreword 2 Text of EN600
6、68-2-66 3BSEN 60068-2-66:1995 ii BSI 05-1999 National foreword This British Standard has been prepared by Subcommittee GEL/50/2 and is the English language version of EN60068-2-66:1994 Environmental testing Part2:Test methods Test Cx: Damp heat, steady state (unsaturated pressurized vapour), publish
7、ed by the European Committee for Electrotechnical Standardization (CENELEC). It is identical with IEC68-2-66:1994 published by the International Electrotechnical Commission (IEC). A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards ar
8、e responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pagesi andii, theEN title page, pages2 to11 and a back cover. This standard has be
9、en updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover.EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN60068-2-66 August1994 ICS19.040 Descriptors: Environmental testing, electricity, component, equipment,
10、 climatic test, damp heat, steady state, unsaturated pressurized vapour, procedures, 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) Ess
11、ais denvironnement Partie 2: Mthodes dessai Essai Cx: Essai continu de chaleur humide (vapeur pressurise non sature) (CEI 68-2-66:1994) Umweltprfungen Teil 2: Prfverfahren Prfung Cx: FeuchteWrme, konstant (ungesttigterDruckdampf) (IEC68-2-66:1994) This European Standard was approved by CENELEC on199
12、4-07-05. CENELEC members are bound 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
13、obtained on application to the Central 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
14、Central Secretariat has the same status as the official versions. CENELEC 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 UnitedKing
15、dom. CENELEC European Committee for Electrotechnical Standardization Comit Europen de Normalisation Electrotechnique Europisches Komitee fr Elektrotechnische Normung Central Secretariat: rue de Stassart 35, B-1050 Brussels 1994 Copyright reserved to CENELEC members Ref. No. EN60068-2-66:1994 EEN6006
16、8-2-66:1994 BSI 05-1999 2 Foreword The text of document50B(CO) 342, as prepared by Subcommittee50B: Climatic tests, of IEC Technical Committee50: Environmental testing, was submitted to the IEC-CENELEC parallel vote in February 1994. The reference document was approved by CENELEC as EN60068-2-66 on
17、5 July 1994. The following dates were fixed: Annexes designated “normative” are part of the body of the standard. Annexes designated “informative” are given only for information. In this standard, Annex A is normative and Annex B, Annex C and Annex D are informative. Contents Page Foreword 2 1 Scope
18、 3 2 General description 3 3 Description of test apparatus 3 4 Severities 3 5 Initial measurements 4 6 Testing 4 7 Intermediate measurements 5 8 Recovery 5 9 Final measurements 5 10 Information to be given in the relevant specification 5 Annex A (normative) Steam table 6 Annex B (informative)Physica
19、l significance of the test 9 Annex C (informative) Determination of humidity 9 Annex D (informative) Test apparatus and handling 10 Figure D.1 Single-vessel type 11 Figure D.2 Dual-vessel type 11 Table 1 Severity 4 Table A.1 Steam 6 latest date of publication of an identical national standard (dop)
20、1995-07-01 latest date of withdrawal of conflicting national standards (dow) 1995-07-01EN 60068-2-66:1994 BSI 05-1999 3 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, p
21、rimarily nonhermetically 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
22、short period. Electrical 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 tempera
23、tures at a relative humidity of85 %. 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 and/or the critical temperature of any encapsulating materials. The glass transition temperature of a plastic i
24、s a typical example 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 cons
25、tructed that: a) it can produce the temperature and relative humidity given in Table 1, and sustain the pressure values given in clause4, note3; 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,
26、specified test conditions; c) the temperature and humidity of the chamber can be monitored by means of sensing devices located in the working space, and/or other areas giving the same results (e.g.a steam generator). NOTEThe direct measurement of relative humidity during this test is not possible wi
27、th current techniques. Guidance on the determination of the relative humidity in the working space is given in Annex C. d) the enclosed atmosphere 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)
28、the materials used in the construction shall not cause any corrosion of the specimen, or degradation of the quality of the humidifying water (see clauseD.2). The temperature tolerance of 2 C is intended to take account of absolute errors in the measurement, fluctuations of the chamber temperature at
29、 any point, and variations between all points within the working space. However, in order to maintain the relative humidity within the specified tolerance of 5 %, it is necessary to keep the difference between any two points in the working space (at any instant) within narrower limits. The specified
30、 humidity tolerance will be exceeded if such temperature differences exceed1,5 C. It is also necessary to restrict the short-term temperature fluctuations due to cycling of the chamber heater to a similar value. The specimen should not significantly impede the vapour flow. Condensation shall not be
31、allowed to form on the specimen at any time during the test. 3.2 The humidifying water Distilled or deionised water shall be used. The water shall have a resistivity of not less than0,5 M7cm at23 C. The pH value shall be between6,0 and7,2 at23 C. Before the water is placed in the humidifier, all int
32、ernal parts of the chamber shall be cleaned. Guidance on cleaning is given in clauseD.4. 4 Severities One of the 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.EN60068
33、-2-66:1994 4 BSI 05-1999 Table 1 Severity NOTE 1It is not recommended 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 III of Table 1, then the test shall be recommenced in accordance with the r
34、equirements of clause6. The test shall be recommenced within96h 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 measurement and tests, unless otherwise specified in the relevant speci
35、fication. NOTE 2The durations given for testing at the specified conditions do not include the additional time required for the ramp-up and ramp-down period and the chamber cleaning and preparation time. NOTE 3The vapour pressures are approximately0,12MPa, 0,17MPa and0,23 MPa at110 C, 120 C and 130
36、C respectively. 5 Initial measurements The specimen shall be submitted to the visual, dimensional and functional checks prescribed 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 inst
37、alled in the working space in the chamber. 6.2 Positioning 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 ther
38、mal capacity of the mounting fixtures shall be low so 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 a
39、nd other mechanisms (see clauseD.2). 6.3 Bias voltage 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
40、 temperature and the relative humidity have reached the stable state, and continue until the specimen is under recovery conditions. 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 expelled from the chambe
41、r 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 within1,5 h. However, if stabilization takes longer
42、than1,5h, the test requirements will be met if stabilization is achieved in not more than3 h and the specified test duration is greater than48 h. 6.4.2 The temperature and relative humidity shall be maintained within the prescribed limits for a duration as specified in the relevant specification. Th
43、e 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 than1 h and not more than4 h. Durin
44、g this period, the temperature and the relative humidity shall not exceed the specified value. The conditions may be achieved by means of natural cooling. Temperature Relative humidity Duration (in hours) c C a % b I II III 110 85 96 192 408 120 85 48 96 192 130 85 24 48 96 a 2 C in the chamber work
45、ing space. b 5 %. c 0, + 2 h.EN60068-2-66:1994 BSI 05-1999 5 If the pressure is reduced by release from the chamber, care shall be taken that the specimen is not subject to rapid depressurization. The pressure shall not fall below the laboratory pressure. The bias should normally be maintained durin
46、g this period. 6.4.4 On completion of the cooling period, the specimen shall be subjected to the recovery procedure. 7 Intermediate measurements The relevant specification may require electrical and/or mechanical checks during testing. If it is required to make intermediate measurements, the relevan
47、t 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 conditions. Measurements preceded by recovery which would require the removal of the specimen from the chamber are not permissible
48、 during testing. 8 Recovery Upon completion of testing, the specimen shall be allowed to recover for not less than2 h and not more than24 h at standard atmospheric conditions for measurement and tests. 9 Final measurements The specimen shall be submitted to the visual, dimensional, and functional ch
49、ecks prescribed by the relevant specification. 10 Information to be given in the relevant specification 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 b) Initial measurements* 5 c) Specific mounting structures 6 d) Bia
