1、 INTERNATIONAL STANDARD IECCEINORME INTERNATIONALE60068-3-11First editionPremire dition2007-05Environmental testing Part 3-11: Supporting documentation and guidance Calculation of uncertainty of conditions in climatic test chambers Essais denvironnement Partie 3-11: Documentation daccompagnement et
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14、rez nous donner des commentaires sur cette publication ou si vous avez des questions, visitez le FAQ du Service clients ou contactez-nous: Email: csciec.ch Tl.: +41 22 919 02 11 Fax: +41 22 919 03 00 INTERNATIONAL STANDARD IECCEINORME INTERNATIONALE60068-3-11First editionPremire dition2007-05Environ
15、mental testing Part 3-11: Supporting documentation and guidance Calculation of uncertainty of conditions in climatic test chambers Essais denvironnement Partie 3-11: Documentation daccompagnement et guide Calcul de lincertitude des conditions en chambres dessais climatiques For price, see current ca
16、taloguePour prix, voir catalogue en vigueur PRICE CODE CODE PRIX V Commission Electrotechnique InternationaleInternational Electrotechnical Commission 2 60068-3-11 IEC:2007 CONTENTS FOREWORD.4 INTRODUCTION.6 1 Scope.7 2 Normative references .7 3 Terms and definitions .8 4 Concept of uncertainty11 4.
17、1 Uncertainty, error and “true value”.11 4.2 Statements of uncertainty12 4.3 Combining uncertainties 13 5 Tolerance .13 6 Humidity and temperature measurement 13 7 Methods for determining climatic test chamber uncertainties 14 7.1 Empty chamber .16 7.2 Typical load.16 7.3 Measurement of conditions i
18、n the chamber during the test 17 7.4 Conditions to measure.17 7.5 Measurements required.18 7.6 Sources of uncertainty.19 7.7 Essential contributions of uncertainty 20 8 Estimation of uncertainty components and their combination 24 9 Overall uncertainty of temperature measurement24 9.1 General .24 9.
19、2 Further considerations.26 10 Overall uncertainty of relative humidity measurement .26 10.1 Uncertainty of temperature measurement at each sensor point27 10.2 Uncertainty of the relative humidity measurement27 11 Anomalous data and presentation of results .30 11.1 Average case analysis.30 11.2 Wors
20、t case analysis 30 Annex A (informative) Measurement data sets Loaded chamber .32 Bibliography34 60068-3-11 IEC:2007 3 Figure 1 Approaches to calibration method and uncertainty calculation15 Figure 2 Illustration of the fluctuation of a temperature sensor .23 Table 1 Combination of temperature uncer
21、tainties .24 Table 2 Combination of temperature uncertainties at each point 27 Table 3 Combination of humidity uncertainties .28 Table A.1 Typical temperature measurement data set and its analysis and refs 32 Table A.2 Humidity measurements analysis based on Table A.1 temperatures.33 4 60068-3-11 IE
22、C:2007 INTERNATIONAL ELECTROTECHNICAL COMMISSION _ ENVIRONMENTAL TESTING Part 3-11: Supporting documentation and guidance Calculation of uncertainty of conditions in climatic test chambers FOREWORD 1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization
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32、e correct application of this publication. 9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of patent rights. IEC shall not be held responsible for identifying any or all such patent rights. International Standard IEC 60068-3-11 has been p
33、repared by IEC technical committee 104: Environmental conditions, classification and methods of test. The text of this standard is based on the following documents: FDIS Report on voting 104/409/FDIS 104/415/RVD Full information on the voting for the approval of this standard can be found in the rep
34、ort on voting indicated in the above table. This publication has been drafted in accordance with the ISO/IEC Directives, Part 2. 60068-3-11 IEC:2007 5 A list of all parts in the IEC 60068 series, under the general title Environmental testing can be found on the IEC website. The committee has decided
35、 that the contents of this publication will remain unchanged until the maintenance result date indicated on the IEC web site under “http:/webstore.iec.ch“ in the data related to the specific publication. At this date, the publication will be reconfirmed, withdrawn, replaced by a revised edition, or
36、amended. 6 60068-3-11 IEC:2007 INTRODUCTION This part of IEC 60068 provides guidance for analysing uncertainties of temperature and humidity in climatic test chambers. It has been written for technicians, engineers and managers in environmental testing, and for anyone who needs to understand the res
37、ults of environmental tests. The performance of climatic test chambers is a key concern in environmental test engineer-ing. To comply with any test specification, the performance of the chamber needs to be characterized to decide whether the generated conditions fall within the specified limits. Thi
38、s characterization can be a difficult task, and the analysis of uncertainties in chamber performance is often surrounded by confusion. This publication is intended to ease that process. In what follows, the concept of uncertainty of measurement is introduced first and then the significance of tolera
39、nce discussed. Aspects of humidity and temperature measurement are considered, followed by methods for determining and combining uncertainties. The cases of both calibrating an empty chamber and of measuring conditions in a loaded chamber are considered. Finally, detailed guidance and worked example
40、s are given for analysing results to give estimates of uncertainty in the measured performance. 60068-3-11 IEC:2007 7 ENVIRONMENTAL TESTING Part 3-11: Supporting documentation and guidance Calculation of uncertainty of conditions in climatic test chambers 1 Scope This part of IEC 60068 demonstrates
41、how to estimate the uncertainty of steady-state temperature and humidity conditions in temperature and humidity chambers. Since this is inextricably linked to the methods of measurement, these are also described. This standard is equally applicable to all environmental enclosures, including rooms or
42、 laboratories. The methods used apply both to temperature chambers and combined temperature and humidity chambers. This standard is meant to help everyone using climatic test chambers. Those already familiar with uncertainty of measurement will find it useful for guidance on typical sources of uncer
43、tainty and how they should be quantified and combined. It is also intended to assist the first-time or occasional user who has little or no knowledge of the subject. To discuss uncertainty, it is important first to understand what is being measured or characterized. The calibration or characterizati
44、on of the performance of a chamber is concerned with the humidity and temperature of the air in the chamber, as experienced by the item under test, at a given set point. This should not be confused with characterizing or calibrating the chamber sensor, which is a separate matter. 2 Normative referen
45、ces The following referenced documents are 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 60068-3-5: Environmental testing Part 3-5
46、: Supporting documentation and guidance Confirmation of the performance of temperature chambers IEC 60068-3-6: Environmental testing Part 3-6: Supporting documentation and guidance Confirmation of the performance of temperature/humidity chambers ISO 3534-1:2006, Statistics Vocabulary and symbols Par
47、t 1: General statistical terms and terms used in probability ISO 3534-2:2006, Statistics Vocabulary and symbols Part 2:Applied statistics International Vocabulary of basic and general standard terms in metrology. ISO, Geneva, Switzerland 1993 (ISBN 92-67-10175-1) VIM 8 60068-3-11 IEC:2007 Guide to t
48、he expression of uncertainty in measurement. ISO, Geneva, Switzerland 1993. (ISBN 92-67-10188-9) GUM 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 calibration authority laboratory or other organization that performs calibrations and is itse
49、lf accredited by the appropriate national accreditation body 3.2 climatic test chamber enclosure chamber or enclosed space where the internal temperature or temperature and humidity can be controlled within specified limits 3.3 combined standard uncertainty standard uncertainty of the result of a measurement when that result is obtained from
