repeatability

Purpose of the work

The aim of this study was to evaluate the evolution of the building airtightness over the time and to assess the long term performance (durability) of the air barrier system. For this purpose, several passive houses were repeatedly tested over a period of 6 to 11 years.

Method of approach

The information about uncertainly is essential to correct interpretation of any measurement. Therefore, several authors investigated the reproducibility and repeatability of airtightness measurement during the last years. The experiments were carried out in real buildings of different size and in actual climatic conditions which complicates the comparison of results. Namely, the question whether the uncertainly is proportional to the measured air flow rate remained unanswered.

Purpose of the work

Due to the wind induced pressure, different results may be obtained if the inside-outside pressure difference is measured across different locations on the building envelope, i.e. if the external pressure tap of a differential pressure sensor measuring this pressure difference is placed in different positions. Therefore, the position of the external pressure tap may influence an airtightness test result as well.

This paper present the results of a test programme to validate the Dutch pre-normative protocol NVN 5623 ‘Radioactivity measurements: Determination of the activity of gamma-ray emitting nuclides in a counting sample by means of semi-conductor gamma-spectr