1、Environment al testing Part 3-7: Supporting doc mentation and guidance - Measurements in temperature chambers for tests A and B (with load) The European Standard EN 40068-3-7:2002 has the status of a British Standard ICs 19.040; 29.020 BS EN IEC 60068-3-712002 60068-3-712001 NO COPYING WITHOUT BSI P
2、ERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW BS EN 60068-3-712002 Amd. No. National foreword Date Comments This British Standard, having been prepared under the direction of the Electrotechnical Sector Policy and Strategy Committee, was published under the authority of the Standards Policy and Str
3、ategy Committee on 19 February 2002 This British Standard is the official English language version of EN 60068-3-7:2002. It is identical with IEC 60068-3-7:2001. The UKparticipation in its preparation was entrusted to Technical Committee GEL/104, Environmental conditions, classification and testing,
4、 which has the responsibility to: - - aid enquirers to understand the text; present to the responsible international/European committee any enquiries on the interpretation, or proposals for change, and keep the UK interests informed; monitor related international and European developments and promul
5、gate them in the UK. - A list of organizations represented on this committee can be obtained on request to its secretary. From 1 January 1997, all IEC publications have the number 60000 added to the old number. For instance, IEC 27-1 has been renumbered as IEC 60027-1. For a period oftime during the
6、 change over from one numbering system to the other, publications may contain identifiers from both systems. Cr oss-r e fer enc e s The British Standards which implement these international or European publications referred to in this document may be found in the BSI Standards Catalogue under the se
7、ction entitled “International Standards Correspondence Index”, or by using 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 applicatio
8、n. 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, the EN title page, pages 2 to 11 and a back cover. The BSI copyright date displayed in this document indicates when the docu
9、ment was last issued. O BSI 19 February 2002 ISBN O 580 39013 6 EUROPEAN STANDARD EN 60068-3-7 NORME EUROPENNE EUROPISCHE NORM Januaw 2002 ICs 19.040; 29.020 English version Environmental testing Part 3-7: Supporting documentation and guidance - Measurements in temperature chambers for tests A and B
10、 (with load) (IEC 60068-3-712001) Essais denviron nement Partie 3-7: Documentation daccompagnement et guide - Mesures dans les chambres dessai en temprature pour les essais A et B (avec charge) (CE1 60068-3-712001) Umweltprfungen Teil 3-7: Untersttzende Dokumentation und Leitfaden - Messungen in Tem
11、peraturprfkammern fr die Prfungen A und B (mit Prfgut) (I EC 60068-3-712001) This European Standard was approved by CENELEC on 2001-12-04. CENELEC members are bound to comply with the CENKENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a nat
12、ional 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. This European Standard exists in three official versions (English, French, German). A version
13、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 members are the national electrotechnical committees of Austria, Belgium, Czech Republic, Denmark
14、, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Malta, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. CENELEC European Committee for Electrotechnical Standardization Comit Europen de Normalisation Electrotechnique Europisches Komitee fr Elektro
15、technische Normung Central Secretariat: rue de Stassart 35, B - 1050 Brussels O 2002 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members. Ref. No. EN 60068-3-7:2002 E Page 2 EN 60068-3-72002 Foreword The text of document 104/211/FDIS, future editi
16、on 1 of IEC 60068-3-7, prepared by IEC TC 104, Environmental conditions, classification and methods of test, was submitted to the IEC-CENELEC parallel vote and was approved by CENELEC as EN 60068-3-7 on 2001-12-04. The following dates were fixed: - latest date by which the EN has to be implemented a
17、t national level by publication of an identical national standard or by endorsement - latest date by which the national standards conflicting with the EN have to be withdrawn (dop) 2002-09-01 (dow) 2004-12-01 This European Standard should be read in conjunction with EN 60068-3-5 and EN 60068-3-6. An
18、nexes 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 not i ce The text of the International Standard IEC 60068-3-7:2001 was approved by CENELEC as a European Standard without any modification. O BS
19、I 19 February 2002 Page 3 EN 60068-3-72002 CONTENTS INTRODUCTION 4 Scope . Normative references Definitions . 6 Measuring system . 7 4.1 Temperature . 7 4.2 Humidity . 7 4.3 Wall emissivity . . 8 4.4 Air velocity . . 8 4.5 Recording device . . 8 Determination of temperature performances . 8 5.1 Test
20、 area environment . . 8 5.2 Chamber loading . 8 5.3 Installation of temperature sensors . . 9 Test procedures 10 6.1 Confirmation methods 6.2 Routine monitoring methods . Evaluation criteria Information to be given in the performance report A Figure 1 - Examples of artificial loads . 7 Figure 2 - Lo
21、cation of wall sensors . 9 Table 1 - Test conditions 6 Table 2 - Artificial load - Values . 7 . Annex ZA (normative) Normative references to international publications with their corresponding European publications 11 O BSI 19 February 2002 Page 4 EN 60068-3-72002 INTRODUCTION IEC 60068 contains fun
22、damental information on environmental testing procedures and severities. T h e ex press i o n “envi ro n m e n t a I con d it i on i n g “ or “e n v i ro n m e n t a I test i n g “ covers t h e n at u r a I a n d artificial environments to which components or equipment may be exposed so that an asse
23、ssment can be made of their performance under conditions of use, transport and storage to which they may be exposed in practice. Temperature chambers used for “environmental conditioning“ or “environmental testing“ are not described in any publication, although the method of maintaining and measurin
24、g temperature and/or humidity has great influence on test results. The physical characteristics of temperature chambers can also influence test results. O BSI 19 February 2002 Page 5 EN 60068-3-72002 ENVIRONMENTAL TESTING - Part 3-7: Supporting documentation and guidance - Measurements in temperatur
25、e chambers for tests A and B (with load) 1 Scope This part of IEC 60068 provides a uniform and reproducible method of confirming that temperature test chambers conform to the requirements specified in climatic test procedures of IEC 60068-2-1 and IEC 60068-2-2, when loaded with either heat-dissipati
26、ng or non heat- dissipating specimens under conditions which take into account air circulation inside the working space of the chamber. This standard is destined primarily for users when conducting regular chamber performance monitoring. 2 Normative references The following referenced documents are
27、indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. IEC 60068-2-1, Environmenfal fesfing - Parf 2: Tesfs - Tesf A: Cold IEC 60068-2-2, Basic
28、 environmenfal fesfing procedures - Parf 2: Tesfs. Tesf 6: Dry heat IEC 60068-3-1, Basic environmenfal fesfing procedures - Parf 3: Background informafion - Secfion one: Cold and dry heaf fesfs IEC 60068-3-5, Environmenfal fesfing - Parf 3-5: Supporfing documenfafion and guidance - Confirmafion of f
29、he performance of femperafure chambers IEC 60068-3-6, Environmenfal fesfing - Parf 3-6: Supporfing documenfafion and guidance - Confirmafion of fhe performance of femperafurelhumidify chambers IEC 60584-1, Thermocouples - Parf 1: Reference fables I EC 60751 , Indusfrial plafinum resisfance fhermomef
30、er sensors O BSI 19 February 2002 Page 6 EN 60068-3-72002 Heat-d i ss i pa ti n g None With I Test Tem perature range 3 Definitions Change of temperature Sudden Gradual For the purpose of this part of IEC 60068, the following definitions apply. 3.1 test specification procedure applied to test chambe
31、rs with or without forced air circulation; suitable for a wide range of chamber sizes NOTE A summary of test conditions in IEC 60068-2-1 and IEC 60068-2-2 is given in the following table: -65 “C to +5 “C Table 1 - Test conditions Aa O O Ab O O Ad O O +30 “C to +400 “C Ba O O Bb O O Bc O O Bd O O 3.2
32、 confirmation method (procedure 1) specified method of making continuous measurements in order to establish whether the performance of a test chamber conforms with the requirements detailed in IEC 60068-2-1, test A and/or IEC 60068-2-2, test B 3.3 routine monitoring method (procedure 2) specified me
33、thod of making measurements, continuously or at intervals, to ensure that the test chamber performance is being maintained 3.4 test load test specimen that is installed in the test chamber for the confirmation measurements NOTE The test load is defined by geometric dimensions and by thermal properti
34、es. 3.5 artificial load test load made in accordance with this standard with dimensions and thermal properties related to the geometric dimensions and thermal capacity of the specimens intended to be tested in the chamber NOTE Table 2 provides values for an artificial load. O BSI 19 February 2002 Pa
35、ge 7 EN 60068-3-72002 Heat transmission Heat radiation emissivity Heat dissipation Table 2 - Artificial load - Values Approximately 10 kJ/m2K 0,7 In accordance with appendix C of IEC 60068-2-2 I Dimensions I Volume approximately 20 % of working space I Airflow IEC 7557/07 NOTE s = 3 mm stainless ste
36、el or 4 mm aluminium (h, I and w should be smaller than the relevant dimensions of the working space). Figure 1 - Examples of artificial loads 4 Measuring system The system used for the confirmation and routine monitoring measurements, either built-in or independent of the chamber, should comply wit
37、h the following requirements. 4.1 Temperature Platinum resistance thermometers (in accordance with IEC 60751) or thermocouples (in accordance with IEC 60584-1) should be used. 4.1.1 Temperature sensor In a temperature range from -200 “C to +200 “C the sensor measurement uncertainty should be in acco
38、rdance with class A of IEC 60751. 4.2 Humidity Required for confirmation of IEC 60068-2-2 tests only. Place the sensor independent of humidity as near as practical to the centre of the working space. O BSI 19 February 2002 Page 8 EN 60068-3-72002 Types of humidity monitoring sensors are described in
39、 4.3 of IEC 60068-3-6. 4.2.1 Humidity sensor Sensor measurement uncertainty should not exceed I3 % RH 4.3 Wall emissivity Emissivity of the chamber enclosure should be in accordance with table IV of appendix J of IEC 60068-3-1. 4.4 Air velocity An airflow sensor should be installed such that the max
40、imum air velocity impinging on the load can be monitored. 4.4.1 Air velocity sensor The air velocity sensor measurement uncertainty should be compatible with IEC 60068-2 tolerances. 4.4.2 The air velocity sensor response time should be greater than 5 s to avoid any influence on it by airflow fluctua
41、tion. Air velocity sensor response time 4.5 Recording device For confirmation monitoring, data should be recorded at least once a minute. For routine monitoring, data should be recorded every 5 min. The device utilized for recording data from the chamber monitoring sensors should be independent of t
42、he chamber control system. 5 Determination of temperature performances 5.1 Test area environment In accordance with 4.1 of IEC 60068-3-5. 5.2 Chamber loading Provision is made for measurement of test chamber performance with different loading co nd it ions. Test loads: heat-d issipating Artificial l
43、oads: heat-d issipating non heat-dissipating non heat-dissipating NOTE However, when testing large, high heat dissipating specimens, it may be desirable to allow the specimen to develop thermal gradients by using free air chambers or those with a low airflow (typically less that 1 m/s). In such case
44、s the chamber may not have a uniform temperature within the working space and it is necessary to monitor the temperatures of the air entering and exiting the specimen. O BSI 19 February 2002 Page 9 EN 60068-3-72002 5.2.1 Location of test load The test load should always be located in the enclosure s
45、o that it is entirely within the working space. For heat dissipating multiple loads, heating effects should be minimized in accordance with the following subclauses of IEC 60068-2-2: no forced air circulation 29.1 .I .2 and 40.1 .I .2, forced air circulation 29.1.2.2 and 40.1.2.2. 5.3 Installation o
46、f temperature sensors The temperature sensors should be protected from heating and cooling sources and from direct heat radiation. In addition, the wall and load sensors should be protected from convection heat transfer from the surrounding air by suitable insulation. 5.3.1 Position of temperature s
47、ensors In accordance with IEC 60068-3-5. 5.3.2 Position of wall sensors When chamber walls are directly heated and/or cooled, additional sensors located in accordance with figure 2 are necessary. IEC 7552/01 Figure 2 - Location of wall sensors 5.3.3 Position of load sensors Test load temperature sen
48、sors should be positioned on representative points of the load to indicate that temperature stability is reached. O BSI 19 February 2002 Page 10 EN 60068-3-72002 6 Test procedures 6.1 Confirmation methods Tests should be conducted at temperatures and with loads which are representative of the intend
49、ed use of the chamber. 6.1.1 Test without load In accordance with IEC 60068-3-5 6.1.2 Test with load - Install and operate the test load. - Repeat test sequence as in 6.1.1 above. 6.2 Routine monitoring methods Routine monitoring should be conducted at regular intervals for control purposes. Additional monitoring should be conducted whenever the chamber undergoes repair/maintenance to the heating/cooling system, the air circulating system or to the chamber control system. Sensors used for routine monitoring should be selected from locations identified in 4.4 of IEC
