airtightness

This work is part of two French research projects “Durabilit'air1” (2016-2019) and “Durabilit'air2” (2021-2024), that aim at improving our knowledge on the variation of buildings envelope airtightness through onsite measurement and accelerated ageing in laboratory-controlled conditions.   
The content presented in this paper is based on two publications in past AIVC conferences (Moujalled et al., 2019, 2018) and a research paper (Moujalled et al., 2021) about the mid-term and long-term changes in building airtightness through on-site measurements in low-energy houses. 

This study sets out to investigate to what extent the air permeability of a building envelope of a dwelling remains constant over longer periods of time. This was evaluated by executing an air pressurisation test in 30 dwellings located in Belgium and comparing these results to the initial measurement results obtained shortly after the construction of the buildings. The time span between both measurements ranges from 293 days to 4045 days. On average, the air infiltration rate of the building envelope increased with 24%, i.e. an increase of 64 m³/h at a 50 Pa pressure difference.

The content presented comes from the Technical Note (TN) 71 “Durability of building airtightness” published on Airbase, the AIVC bibliographic database.

Low or Zero Energy buildings are becoming increasingly popular and the use of passive-house principles are providing a solid foundation for achieving energy consumption targets and good indoor quality. However, this design methodology has been well received in central and northern Europe than in south and the Mediterranean, where people are used to houses that are open to the external environment. This habit is in contrast to the basic principles of the good airtightness, the energy efficiency and the achievement of a good Indoor Air Quality.

Calcium Silicate fire protection boards can be used to construct fireproof ductwork for smoke extraction and/or HVAC services. In this paper, the airtightness of the duct system is evaluated. 

Many European programs offer eco-conditioned financial aid to support public policies for the decarbonization of buildings. This is the case, for example, of the 2017-2022 ERDF Operational Program, which financially assists social project management for energy efficient refurbishment operations of its building stock. The eligibility conditions for financial aids concern the energy consumption, the thermal insulation performance of the building envelope and the energy efficiency of heating, cooling and ventilation systems.

Room pressure differential is an important aspect in order to guarantee sufficient contamination control, but is difficult to control in airtight cleanrooms. This research uses simulation models to get an understanding and to quantify the room pressure controllability of airtight cleanrooms. The most influential parameters on the room pressure controllability are identified using a sensitivity analysis. The effects of the shell airtightness and overflow flowrates are quantified, and the effect of a flow/pressure cascade with three coupled rooms is investigated.

Building air infiltration rate is required as an important input in the calculation of building heat loss. Tests to directly measure infiltration rates are complex and time-consuming to perform, and are therefore usually substituted with an airtightness test as a more efficient alternative. An empirical ratio, or sometimes an infiltration model, is then used to predict the building infiltration rate from the measured airtightness value. For instance, in the United Kingdom the building air permeability measured by a steady pressurisation test and reported at 50 Pa

Air leakage in building envelopes is responsible for a large portion of the building’s heating and cooling requirements. Therefore, fast and reliable detection of leaks is crucial for improving energy efficiency.