1、BRITISH STANDARD BS EN 60721-3-9: 1993 IEC 721-3-9: 1993 Incorporating Amendment No. 1 Classification of environmental conditions Part 3: Classification of groups of environmental parameters and their severities Section 3.9 Microclimates inside products The European Standard EN 60721-3-9:1993 has th
2、e status of a BritishStandard UDC 621.3:620.193BSEN60721-3-9:1993 This British Standard, having been prepared under the directionof the General Electrotechnical Standards PolicyCommittee, was publishedunder the authority ofthe Standards Board and comesinto effect on 15December1993 BSI 12-1999 The fo
3、llowing BSI references relate to the work on this standard: Committee reference GEL/15 Special announcement in BSINews, November 1993 ISBN 0 580 22646 8 Cooperating organizations The European Committee for Electrotechnical Standardization (CENELEC), under whose supervision this European Standard was
4、 prepared, comprises the national committees of the following countries: Austria Italy Belgium Luxembourg Denmark Netherlands Finland Norway France Portugal Germany Spain Greece Sweden Iceland Switzerland Ireland United Kingdom Amendments issued since publication Amd. No. Date Comments 8954 December
5、 1995 Indicated by a sideline in the marginBSEN60721-3-9:1993 BSI 12-1999 i Contents Page Cooperating organizations Inside front cover National foreword ii Foreword 2 Text of EN 60721-3-9 3 National annex NA (informative) Committees responsible Inside back cover National annex NB (informative) Cross
6、-references Inside back coverBSEN60721-3-9:1993 ii BSI 12-1999 National foreword This British Standard has been prepared under the direction of the General Electrotechnical Standards Policy Committee and is the English language version of EN 60721-3-9:1993 Classification of environmental conditions
7、Part3. Classification of groups of environmental parameters and their severities Section 9. Microclimates inside products, published by the European Committee for Electrotechnical Standardization (CENELEC). It is identical with IEC 721-3-9:1993 published by the International Electrotechnical Commiss
8、ion (IEC). In 1994 the European Committee for Electrotechnical Standardization (CENELEC) accepted the text of Amendment 1:1994 to IEC 721-3-9:1993 as Amendment 1:1995 to EN 60721-3-9:1993. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Sta
9、ndards are 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, pages i and ii, theEN title page, pages2 to 10, an inside back cover and
10、a back cover. This standard has been 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 EN 60721-3-9 September 1993 + A1 March 1995 UDC 621.3:620.193 Descript
11、ors: Electronic components, electrotechnical components, electric equipment, electronic equipment, environment, climate, climatic conditions, classification English version Classification of environmental conditions Part3:Classification of groups of environmental parameters and their severities Sect
12、ion9:Microclimatesinsideproducts (includes amendment A1:1995) (IEC 721-3-9:1993) Classification des conditions denvironnement Partie 3: Classification des groupements des agents denvironnement et de leurs svrits Section 9: Microclimats lintrieur des produits (inclut lamendement A1:1995) (CEI 721-3-9
13、:1993) Klassifizierung von Umweltbedingungen Teil3: Klassen von Umwelteinflugren und deren Grenzwerte Hauptabschnitt9:Mikroklimate innerhalb von Erzeugnissen (enthlt nderungen A1:1995) (IEC 721-3-9:1993) This European Standard was approved by CENELEC on 1993-07-06. CENELEC members are bound to compl
14、y 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 Central Secr
15、etariat 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 status as
16、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 United Kingdom. CENELEC European Committee for Electr
17、otechnical Standardization Comit Europen de Normalisation Electrotechnique Europisches Komitee fr Elektrotechnische Normung Central Secretariat: rue de Stassart 35, B-1050 Brussels 1993 Copyright reserved to CENELEC members Ref. No. EN 60721-3-9:1993 + A1:1995 EEN60721-3-9:1993 BSI 12-1999 2 Forewor
18、d The text of document 75 (CO) 80, as prepared by IEC Technical Committee No. 75: Classification of environmental conditions, was submitted to the IEC-CENELEC parallel vote in October 1992. The reference document was approved by CENELEC as EN 60721-3-9 on 6 July 1993. The following dates were fixed:
19、 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 informative and Annex ZA is normative. Foreword to Amendment A1 The text of document 75(CO)106, future amendment 1 to IEC 721-3-9:1993,
20、prepared by IECTC 75, Classification of environmental conditions, was submitted to the IEC-CENELEC parallel vote and was approved by CENELEC as amendment A1 to EN 60721-3-9:1993 on 1995-03-06. The following dates were fixed: Contents Page Foreword 2 1 Scope 3 2 Normative references 3 3 Definitions 3
21、 4 General 4 5 Classification of microclimatic conditions 4 6 Types and marking of microclimatic classes 5 Annex A (informative) Graphical presentationandpreferred microclimatic classes 6 Annex ZA (normative) Other international publications quoted in this standard with the references of the relevan
22、t European publications 9 Figure A.1 Example of a climatogram for a microclimate: Microclimatic class 4K2/X2/Y3 7 Table 1 Classification of microclimatic conditions 4 Table A.1 Characteristic parameters and severities of microclimatic classes Weatherprotected locations 8 Table A.2 Characteristic par
23、ameters and severities of microclimatic classes Non-weatherprotected locations 8 latest date of publication of an identical national standard (dop) 1994-07-01 latest date of withdrawal of conflicting national standards (dow) 1994-07-01 latest date by which the amendment has to be implemented at nati
24、onal level by publication of an identical national standard or by endorsement (dop) 1996-03-01 latest date by which the national standards conflicting with the amendment have to be withdrawn (dow) 1996-03-01EN60721-3-9:1993 BSI 12-1999 3 1 Scope This section of IEC 721-3 defines classes of microclim
25、atic conditions, to which components (basic parts, assemblies, built-in units) may be subjected inside products, which are used under the climatic conditions as classified in sections IEC 721-3-3 and IEC 721-3-4. Characteristic parameters for the microclimates are high air temperature and high relat
26、ive air humidity. Further parameters of the climatic classes e.g. low temperature may affect the components additionally, but have not been considered here. A limited number of microclimatic classes is specified taking into consideration typical limiting high air temperatures of components. The user
27、 of this standard should select the lowest class necessary for covering the intended use. 2 Normative references The following normative documents contain provisions which, through reference in this text, constitute provisions of this section of IEC 721-3. At the time of publication, the editions in
28、dicated were valid. All normative documents are subject to revision, and parties to agreements based on this section of IEC721-3 are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. Members of IEC and ISO maintain registers of
29、 currently valid International Standards. IEC 721-1:1990, Classification of environmental conditions Part 1: Environmental parameters and their severities. IEC 721-2-1:1982, Classification of environmental conditions Part 2: Environmental conditions appearing in nature Section 1: Temperature and hum
30、idity. Amendment 1 (1987) IEC 721-3-0:1984, Classification of environmental conditions Part 3: Classification of groups of environmental parameters and their severities Section 0: Introduction. Amendment 1 (1987) IEC 721-3-3:1987, Classification of environmental conditions Part 3: Classification of
31、groups of environmental parameters and their severities Section 3: Stationary use at weatherprotected locations. Amendment 1 (1991) IEC 721-3-4:1987, Classification of environmental conditions Part 3: Classification of groups of environmental parameters and their severities Section 4: Stationary use
32、 at non-weatherprotected locations. Amendment 1 (1991) 3 Definitions In addition to the definitions in clause 3 of IEC 721-1 the following definitions apply to this standard: 3.1 microclimate the climatic condition at the place where a component is installed in the product. Only air temperature and
33、air humidity are taken into account 3.2 microclimatic class a classified microclimate designated by: the climatic class as specified in IEC 721-3-3 or IEC 721-3-4; the class of high air temperature see Table 1 a); the optional class of limited relative air humidity, in relation to the climatic class
34、 severity seeTable 1 b).EN60721-3-9:1993 4 BSI 12-1999 4 General Microclimates at the place where the components are installed in a product may differ significantly from the climatic conditions to which the product is subjected. The microclimates describe the climatic conditions at the place where t
35、he component is installed in a product e.g. inside an enclosure. These are essentially the climatic classes specified in IEC 721-3-3 or IEC721-3-4 but with the addition of severities of high air temperature and limited relative air humidity to account for external or appreciable self-generated heati
36、ng during operation. Microclimates can also be used to designate the operational conditions for components. When temperatures in excess of those of the environment itself occur inside a product, the relative air humidity and, therefore, also the humidity stress on the components is reduced. Even in
37、environments with a relative air humidity as high as 100%, the relative air humidity inside the product is reduced below65% by an excess temperature of10 C. Below this humidity level the corrosion effect of chemically active substances is very low. The microclimates described concern the case of pla
38、cing of components in enclosures with comparatively free access to the surrounding atmosphere. Difficult access of air (e.g. presence of non-tight seal of the enclosure) may produce more severe conditions as a result of suction of moisture into the enclosure and subsequent accumulation of water. Thi
39、s can result from frequent switching on and off of the product or rapid changes of temperature inside the product due to external climatic conditionse.g.rain, irradiation. Components in products without external heating or self-generated heating or in the non-operational state for a significant peri
40、od of time are affected directly by the conditions of the climatic class appropriate for a location. When changing between the climatic conditions with and without external heating or self-generated heating, the time for which the component is subjected to the climatic conditions has to be taken int
41、o consideration. For details on duration and frequency of occurrence, the values specified in IEC 721-3-0, Amendment 1 should be selected. For further guidance, see IEC 721-3-0. 5 Classification of microclimatic conditions The severities of high air temperature and of limited relative air humidity f
42、or a number of microclimatic classes are specified in Table 1. Table 1 Classification of microclimatic conditions Examples for the designation and marking of microclimatic classes are given in clause 6. Exceptional conditions may call for severities different from those of the classes; these should
43、be selected from the values specified in IEC 721-1. The graphical representation of a microclimatic class is given in clause A.1 of Annex A from which two characteristic corner points can be determined. For a selection of preferred microclimatic classes paired values of air temperature and relative
44、air humidity are stated in Table A.1 and Table A.2 of Annex A. The method described in Annex A, applies to the period of time when microclimatic conditions have reached a steady state. Environmental parameter Class Unit Severity a) High air temperature X1 X2 X3 X4 X5 X6 X7 C 55 70 85 100 125 155 200
45、 b) Limited relative air humidity Y1 Y2 Y3 Y4 % 65 75 85 95EN60721-3-9:1993 BSI 12-1999 5 6 Types and marking of microclimatic classes A microclimatic class is marked with the appropriate class designation of the climatic class of the product and the appropriate class designation of Table 1. Example
46、 1 Increased air temperature only Example 2 Increased air temperature and limited relative air humidity Example 3 Increased air temperature, limited relative air humidity and direct influence of the climatic class limited in timeEN60721-3-9:1993 6 BSI 12-1999 Annex A (informative) Graphical presenta
47、tion and preferred microclimatic classes A.1 Graphical presentation of the microclimatic classes The climatogram described in the following and shown in Figure A.1 is drawn on the constitutional diagram for humid air defined in Appendix B of IEC 721-2-1. Figure A.1 is an example of the climatogram o
48、f microclimatic class 4K2/X2/Y3. The characteristic points and lines of the climatogram are obtained in the following manner: Draw the climatogram of climatic class 4K2. Mark the cornerpoints by A, B, C, D, E: A is the high air temperature at high absolute air humidity; B is the high relative air hu
49、midity at high absolute air humidity; C is the low air temperature at high relative air humidity; D is the low relative air humidity at low absolute air humidity; E is the high air temperature at low relative air humidity. Determine the difference between the air temperature of the microclimate (70 C) and the high air temperature of the climatic class (40 C) i.e. 30 C Shift the corner points A to E by the value of this difference between the high air temperatures of the microc
