Database

The content presented comes from the paper under review “Quantitative correlation between buildings air permeability indicators: statistical analyses of about 500,000 measurements” (Moujalled, 2023a).

The need for airtightness control is a reality given its impact on buildings’ energy use and IAQ. For the past few years, this fact has resulted in energy performance regulations being established in many countries in Europe and North America. However, compliance proof is not always required, and on-site testing is often avoided. In this sense, predictive models have become useful in the decision-making process and to estimate input values in energy performance simulation tools.

With the constant evolution of the French EP-regulations, good building airtightness has become mandatory to reach required energy performance. More than 60,000 airtightness tests are performed each year since 2015. Each measurement performed by a qualified tester must be recorded in a national database that is therefore growing fast (more than half million in 2020).

Purpose of the work

Since 2008 in France, all measurement of building envelope airtightness performed according to the EP-regulations have to be performed by a certified operator. This certification includes a yearly follow-up we use to build up a highly detailed database which includes data of about 90,000 airtightness measurements.

Method of approach

A ventilation performance report is mandatory for every new residential building in Flanders, for building permits issued since January, 1st 2016. This means that the features of the ventilation system as installed in the dwelling must be reported and that, in the EPB-report of the dwelling, these data must be used to justify the energy performance of the ventilation system. 

To enhance the properly functioning of the ventilation systems, a ventilation preliminary design has to be made before the physical building process is started. 

This paper summarizes the most recent results of the French database of ductwork airtightness. This database was created in 2016. It is fed through measurements performed by qualified testers according to a national scheme regarding ductwork. Measurements are mainly performed in building applying for the Effinergie + label which requires class A for ductwork airtightness. Therefore, results discuss in this paper only apply to the buildings of the database and cannot be generalized to all new buildings in France.

The air leakage impact on energy performance in buildings has already been broadly studied in USA, Canada and most European countries. However, there is a lack of knowledge in Mediterranean countries regarding airtightness. An extensive study has been carried out in order to characterize the envelope of the existing housing stock in Spain. Preliminary results of more than 401 dwellings tested are shown. The sample includes different typologies, year of construction and climate zones. Blower door tests were performed and thermal imaging was used to locate leakage paths.   

The French database of building airtightness has been fed by measurement performed by qualified testers since 2006. In 2015 and 2016, the database was enriched by 63,409 and 65,958 measurements respectively, which is 74% more than in 2014, making the total number of measurements about 215,000. However, residential buildings (multi-family and single dwellings) account for almost all of measurements, only 4% of tests are performed in non-residential buildings. Indeed, since 2013 the French EP-regulation requires a limit for airtightness level for all new dwellings.

Since January 1st, 2018, airtightness testing has become implicitly mandatory for every new residential building in Flanders. There is no minimum requirement for airtightness. However, there is one for the global performance of the building envelope (S-level, taking into account thermal insulation, airtightness, solar gains, etc.), and a poor airtightness would jeopardize the chance to reach the required S-level.

Since 2000, the French EP-calculations have been considering thermal losses due to building envelope airtightness. The last two regulations (RT2000 and RT2005) had included a default value for airtightness and the possibility to use a better-than-default value with a mandatory justification of this value, especially for voluntary approaches such as the BBC-Effinergie label. In 2013, strengthening the airtightness has become a requirement of the current EP-regulation (RT2012).