Quicker measurement of walls' thermal resistance following an extension to ISO 9869 average method

Arash Rasooli*, Laure Itard

*Corresponding author for this work

Research output: Contribution to journalConference articleScientificpeer-review

1 Citation (Scopus)
100 Downloads (Pure)


Determination of the thermo-physical characteristics of the buildings' components is crucial to illustrate their thermal behavior and therefore their energy consumption. Along the same line, accurate determination of the thermal resistance of the building walls falls into one the most important targets. Following the difference between in-lab, and on site thermal performance of walls, in-situ measurements have been highly recommended. The most well-known practice for in-situ measurement of walls' thermal resistance is the Average Method of ISO 9869, using one heat flux meter and two thermocouples. The method, in comparison with other existing methods is quite straight-forward and therefore, is applied widely in large scale. Despite its simplicity, this method usually needs a relatively long time to reach an acceptable result. The current paper deals with a modification to the ISO 9869 method, making it in many situations much quicker than its original state. Through simulation of walls of different typologies, it is shown in which cases the measurement period becomes longer than expected. It is demonstrated how the addition of a heat flux meter to the aforementioned equipment can lead to a much quicker achievement of the thermal resistance, following the rest of the instructions of the standard method.

Original languageEnglish
Article number04019
Number of pages6
JournalE3S Web of Conferences
Publication statusPublished - 2019
EventCLIMA 2019: REHVA 13th HVAC World Congress: Built Environment Facing Climate Change - Bucharest, Romania
Duration: 26 May 201929 May 2019


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