IEC TR 63250:2021

Overview

IEC TR 63250:2021 - Household and similar electrical appliances - Method for measuring performance - Assessment of repeatability, reproducibility and uncertainty - is a Technical Report from the IEC that provides guidance on assessing the precision and measurement uncertainty of test methods used for household and similar electrical appliances. The report describes how to determine repeatability (intra‑laboratory variability) and reproducibility (inter‑laboratory variability), how to carry out and analyse round robin tests (RRTs), and how to report uncertainty for measured performance characteristics. It does not cover development of measurement methods, production variability of appliances, or how closely methods reflect normal household use.

Key Topics and Requirements

• Repeatability and reproducibility assessment: Procedures for estimating standard deviations that characterise intra‑ and inter‑laboratory variability.
• Round robin tests (RRTs): Guidance on planning, conducting and analysing inter‑laboratory comparisons to derive reproducibility and repeatability figures.
• Uncertainty estimation and reporting: Methods to estimate measurement uncertainty (including expanded uncertainty) and to predict measurement ranges when the same appliance is measured in another laboratory.
• Scrutiny and outlier testing: Techniques for checking consistency and identifying outliers, including graphical and numerical methods such as Mandel’s h and k statistics, Cochran’s C test, and Grubbs’ test.
• Data reporting: Recommended data and formats to report for reproducibility, repeatability and uncertainty assessments.
• Informative annexes: Practical examples (bottom‑up uncertainty analysis), detailed RRT procedures, worked RRT example and sample result expressions to aid implementation.

Applications and Who Uses It

IEC TR 63250 is intended for organisations involved in measurement and conformity assessment of household appliances:

• Testing laboratories conducting performance measurements who need to quantify precision and uncertainty.
• Manufacturers validating test methods and documenting measurement uncertainty for product declarations.
• Regulators and policy makers designing test programs or schemes that rely on inter‑laboratory comparability.
• Standards developers and technical committees using RRTs to set reproducibility/precision requirements for normative test standards.
• Certification bodies and third‑party assessors verifying reported values against declared limits.

Practical uses include designing RRTs, estimating measurement uncertainty for energy/water performance claims, and comparing laboratory results across jurisdictions.

Related Standards (if applicable)

IEC TR 63250 was developed following IEC procedures and complements other international guidance on measurement uncertainty and inter‑laboratory testing. Users should consult relevant IEC and ISO guidance documents and national normative references when applying the report.