CETE de Lyon gives support to French administration for thermal regulation definition and enforcement. They must therefore work on measurements in order to set appropriate requirements and give advice to professionals about building methods.

A large social housing retrofitting program was implemented in Porto, Portugal, a mild climate region. One of the features of that program was the upgrade of windows and ventilation systems. An increased airtightness was expected and mechanical extraction on kitchens and bathrooms was implemented. This work analyses the changes in building airtightness that resulted from that renovation.

In this paper we present a series of leakage tests on extremely airtight dwellings (ACH50 < 0.6 upon completion) in which the durability of the airtightness and the measurement uncertainty involved are assessed. In literature, repeatability and reproducibility issues have been discussed by several authors, along with influences of weather. It remains unclear, however, to what extent the available uncertainty intervals are relative or absolute.

The paper presents a calculation method for the combined standard uncertainty associated with the buildings airtightness measurement done in accordance with the ISO standard 9972:2006 (or EN 13829).

The method consists in an application of the law of propagation of uncertainty (JCGM 100:2008) combined with a linear regression (y = a x + b). It goes from the measured values to the air leakage rate and the air change rate.

Ventilation’s historical goal has been to assure sufficient air change rates in buildings from a hygienic point of view. Regarding its potential impact on energy consumption, ventilation is being reconsidered. An important challenge for low energy buildings lies in the need to master airflows through the building envelope.

Reducing adventitious infiltration in order to save energy is important and is highlighted by the building standards of many countries.  This operational infiltration is often inferred via the measurement of the air leakage rate at a pressure differential of 50 Pascals.  Some building codes, such as the UK’s Standard Assessment Procedure, assume a simple relationship between the air leakage rate and mean infiltration rate during the heating season, the so-called leakage-infiltration ratio, which is scaled to account for the physical and environmental properties of a dwelling.  The scaling d

Pushed at first by the labels backed onto the 2005 French energy performance (EP) regulation, and later on by the 2012 energy performance regulation, which imposes envelope airtightness requirements for any new dwellings, and pulled by a growing interest for low-energy labels, an important market transformation is observed in France on envelope airtightness measurement.

Since January 1st 2013, the French energy performance (EP) regulation requires building airtightness level to be justified to a lower-than-required value. These requirements represent an important change in the airtightness market. As a consequence, it is the State’s responsibility to accompany this market evolution and to supervise the implementation of the quality in building airtightness. French regulation allows two ways to justify the airtightness value for the building envelope.

From 2006 till 2012, the 2005 energy performance (EP) regulation (RT 2005) did not entail any obligation to justify the envelope airtightness level. As a consequence, asking for the certification of airtightness quality management approaches was a voluntary request from constructors. Thus, they might be allowed to take into account a better-than-default value into the thermal calculation. Since 2012, French 2012 EP regulation (RT 2012) requires building airtightness level to be justified, with two ways of justification.