English

Natural and Hybrid ventilation systems, by using exclusively or partially natural driving forces, help to reconcile building energy sobriety and good Indoor Air Quality (IAQ). However, in France, Building Regulations restrict the use of natural ventilation by imposing minimum airflows in buildings. Natural ventilation, whose driving forces are atmospheric conditions, has an efficiency depending on the climatic region.

Indoor environment and indoor air quality (IAQ) are considered as subjects of major concern: as we build more and more energy efficient and airtight buildings, the conflicting issues of energy efficiency, adverse health effects and discomfort become more relevant. Significant rates of malfunctions of ventilation systems are still observed among new constructions.

In France, the new Promevent protocol for ventilation system inspection in new dwellings has been published in 2017. It proposes a complete method for checks and measurements in order to uniform and improve the quality of inspection performed by measurers. The Promevent protocol proposes a methodology for pre-check, functional checks, functional measurements at air terminal devices and ductwork airtightness measurement. It also includes requirements for sampling and gives guidelines for the report.

The “VIA-Qualité” project (2013-2016) aims at developing quality management (QM) approaches (ISO 9001) on ventilation and indoor air quality (IAQ), for low-energy, single-family buildings. The goal of these QM approaches is to improve both ventilation and IAQ actual in-situ performance. The main benefits of those approaches are to: 1-Improve ventilation system performance from design to implementation; 2-Limit indoor internal pollution sources, monitoring building materials selection and design regarding the outdoor pollution sources; 3-Improve final users understanding. 

One of the main factors influencing building airtightness is the construction typology. As building environmental performance requirements raise so does the prevalence of less conventional envelope construction systems as modular structural insulated panels (SIPs) buildings.  

The increasing weight of building leakages energy impact on the overall energy performance of low-energy buildings led to a better understanding of the actual airtightness performance of buildings. However, low expertise is available today on the durability of airtightness products in mid- and long-term scales. The French ongoing research project “Durabilit'air” (2016-2019) aims at improving our knowledge on the variation of buildings airtightness through onsite measurement and accelerated ageing in laboratory controlled conditions.

In this study, durability of building airtightness was assessed by means of repeated airtightness testing of the studied houses. This approach generally involves the following issues which complicate the comparison of the test results: 

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.