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Over the last three years the understanding, adoption and use of BIM has gained international momentum.

With the increasing need for higher energy efficiency in buildings, airtightness and ventilation systems choice become major performance issues in well insulated buildings. Buildings energy requirements lead to adapt ventilation strategies in order to reduce energy losses through mechanical balanced or extract ventilation. With the new French thermal regulation, the use of energy-efficient ventilation systems is implicitly required; low air infiltration is explicitly required in residential buildings through minimum airtightness levels.

During the construction of a multi-family residential building the developer decided that the building must comply with the airtightness requirements for passive houses. Based on inspection work and preliminary testing, the original design was revised. The execution of the new air barrier system was supervised. Selected flats were repeatedly tested during the construction process. The whole building was tested once before the completion of the construction. After the completion of the building, all the flats, the whole building and the staircase were tested again.

Legislative drivers and new research with demonstrated energy impact on the importance of building and ductwork airtightness are leading to increased activity in this aspect of building energy performance. The paper reviews examples of European countries that account for both building and ductwork airtightness and thus include in their energy performance regulations required or recommended minimum airtightness levels with or without mandatory testing. It addresses incentives through calculation procedures and subsidies that reward a good level of building airtightness.

At present, a lot of test methods for leakage detection exist. Most of them have a limited application mainly due to possibility of recording, repeatability or reproducibility of the measured results. The aim of the research was creation of a test method to be incorporated into Czech technical standard

The improvement of air tightness in existing residential buildings could be triggered from the desire for better indoor comfort conditions and the expected reduction of cost for space heating. While the improvement of comfort sensation could not be easily understood from the building owner, the reduction of cost for space heating is much easier.

Laboratory measurements have been performed to investigate the airtightness of clamped joints in the wind- and vapour layers. Air leakage was measured immediately after mounting with moisture content of the wooden members at approximately 17 weight %, and after drying down to approx. 7 weight %. It was found that screws as fasteners provided better airtightness than nails. Center distance of 600 mm resulted in general higher air leakages than shorter center distances like 300 mm or 150 mm.

As operator of the Blower Door-test we often come in for a dilemma when government regulations shall be documented. According the standard the test shall be performed on the finished building, but the contractor would like to know if the buildings envelop is airtight as early as possi-ble. A traditional Blower Door-test it often possible for the first time when the building stands nearly completely finished.  The problem becomes even more distinctly when we speak about large buildings, where it always becomes finished in sections.

This paper analyses approaches for setting airtightness requirements whether in voluntary or regulatory schemes. We have classified approaches for upper limits into two major types: default values and minimum requirement. Lessons learnt from existing schemes where minimum requirements have been enforced show that the scheme to justify a given airtightness level is one fundamental ingredient in terms of market impact.