IEC TR 63250:2021

Household and similar electrical appliances - Method for measuring performance - Assessment of repeatability, reproducibility and uncertainty

IEC TR 63250:2021 deals with the determination of repeatability and reproducibility of test methods used for assessing the performance characteristics of household and similar electrical appliances. It also provides guidance for carrying out round robin tests (RRT).
It also specifies the uncertainty reporting of measurements of household and similar electrical appliances.
It describes methods to estimate the uncertainty of a measured result and to predict the range of measured values when the same appliance is measured in another laboratory applying the same measurement method.
It does not cover the development of measurement methods. It also does not deal with:
– the production variability of the appliance;
– how closely the measurement method reflects the normal use of appliances in households.

General Information

• Status: Published
• Publication Date: 23-Jun-2021
• ICS: 97.030 - Domestic electrical appliances in general
• Technical Committee: TC 59 - Performance of household and similar electrical appliances
• Drafting Committee: WG 18 - TC 59/WG 18
• Current Stage: PPUB - Publication issued
• Start Date: 23-Jul-2021
• Completion Date: 24-Jun-2021

Standards Content (Sample)

IEC TR 63250 ®
Edition 1.0 2021-06
TECHNICAL
REPORT
Household and similar electrical appliances – Method of measuring
performance – Assessment of repeatability, reproducibility and uncertainty
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IEC TR 63250 ®
Edition 1.0 2021-06
TECHNICAL
REPORT
Household and similar electrical appliances – Method of measuring

performance – Assessment of repeatability, reproducibility and uncertainty

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 97.030 ISBN 978-2-8322-9939-5

– 2 – IEC TR 63250:2021 © IEC 2021
CONTENTS
FOREWORD . 4
INTRODUCTION . 6
1 Scope . 7
2 Normative references . 7
3 Terms and definitions . 7
4 Determination of standard deviations . 10
4.1 General . 10
4.2 Repeatability standard deviation . 10
4.3 Reproducibility standard deviation . 10
5 Assessment of repeatability, reproducibility, and uncertainty of a measurement
method . 11
5.1 Purpose . 11
5.2 Requirements . 11
5.3 Expression of repeatability and reproducibility . 12
5.4.1 The importance of the uncertainty . 12
5.4.2 Methods to estimate uncertainty . 12
5.4.3 Expanded uncertainty calculation . 13
6 Scrutiny of results for consistency and outliers . 14
6.1 Purpose . 14
6.2 Graphical consistency technique (Mandel's h and k statistics) . 14
6.2.1 Inter-laboratory consistency statistic h . 14
6.2.2 Intra-laboratory consistency statistic k . 14
6.2.3 Evaluation . 14
6.3 Numerical outlier technique . 15
6.3.1 Cochran's C test . 15
6.3.2 Grubbs' test . 15
6.3.3 Evaluation . 15
7 Data to be reported for assessing the repeatability, reproducibility and uncertainty
of a test method. 16
Annex A (informative)  Example of bottom-up analysis . 17
A.1 General . 17
A.2 Temperature measurement system . 17
A.2.1 General . 17
A.2.2 Calibration of thermocouples . 17
A.2.3 Calibration of the DAQ system . 17
A.3 Uncertainty temperature measurement . 17
A.4 Analysis of each component in the uncertainty formulation, example
thermocouple simulator . 19
Annex B (informative)  Guidance on how to conduct round robin tests for household
and similar electrical appliances . 21
B.1 General . 21
B.2 Scope . 21
B.3 Process and responsibilities . 22
B.3.1 Process . 22
B.3.2 Responsibilities . 23
B.4 Testing laboratories . 23

B.4.1 Potential laboratories . 23
B.4.2 Announcement. 23
B.4.3 Selection of laboratories . 24
B.4.4 Final list of laboratories . 24
B.5 Transportation of the product . 24
B.5.1 Logistics . 24
B.5.2 Packaging. 24
B.6 Test . 24
B.6.1 Performance of test . 24
B.6.2 Laboratory visit . 25
B.6.3 Transmission of result . 25
B.7 Analysis, report and termination . 25
B.7.1 Analysis . 25
B.7.2 Report . 25
B.7.3 Termination and publication of final external report . 26
Annex C (informative)  Example of a round robin test and its analysis. 27
C.1 General . 27
C.2 Standard deviations and assessment of repeatability and reproducibility . 27
C.3 Scrutiny of results for consistency and outliers. 29
C.3.1 Example of Mandel's h and k statistics . 29
C.3.2 Example of numerical outlier test . 29
Annex D (informative) Example of expression of results . 32
Bibliography . 33

Figure 1 – Visualisation of straggler and outlier of Cochrane value . 16
Figure C.1 – Mandel's h statistics. 30
Figure C.2 – Mandel's k statistics . 31

Table A.1 – Description of uncertainty parameters . 18
Table A.2 – Measuring a temperature of −23 °C at a climate room temperature
between 16 °C to 32 °C . 19
Table A.3 – Expanded uncertainty in measured temperature (U(T), k = 2) at a room
temperature in the range of 16 °C to 32 °C and a lab temperature between 14 °C and

32 °C . 19
Table A.4 – Calibration results of the simulator . 20
Table C.1 – Measurement results . 27
Table C.2 – Standard deviations, repeatability and reproducibility . 28
Table C.3 – Mandel's h and k statistics . 29
Table C.4 – Cochran's test C and Grubbs' test G . 29
Table C.5 – Cochran's test C and Grubbs' test G summary . 30

– 4 – IEC TR 63250:2021 © IEC 2021
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
HOUSEHOLD AND SIMILAR ELECTRICAL APPLIANCES –
METHOD OF MEASURING PERFORMANCE – ASSESSMENT OF
REPEATABILITY, REPRODUCIBILITY AND UNCERTAINTY

FOREWORD
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