IEC 60068-3-11:2007

FOREWORD
INTRODUCTION
1 Scope
2 Normative references
3 Terms and definitions
4 Concept of uncertainty
   4.1 Uncertainty, error and 'true value'
   4.2 Statements of uncertainty
   4.3 Combining uncertainties
5 Tolerance
6 Humidity and temperature measurement
7 Methods for determining climatic test chamber
   uncertainties
   7.1 Empty chamber
   7.2 Typical load
   7.3 Measurement of conditions in the chamber during
        the test
   7.4 Conditions to measure
   7.5 Measurements required
   7.6 Sources of uncertainty
   7.7 Essential contributions of uncertainty
8 Estimation of uncertainty components and their
   combination
9 Overall uncertainty of temperature measurement
   9.1 General
   9.2 Further considerations
10 Overall uncertainty of relative humidity measurement
   10.1 Uncertainty of temperature measurement at each
        sensor point
   10.2 Uncertainty of the relative humidity measurement
11 Anomalous data and presentation of results
   11.1 Average case analysis
   11.2 Worst case analysis
Annex A (informative) Measurement data sets - Loaded chamber
Bibliography

Demonstrates 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 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 uncertainty 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 characterization 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.