Multizone air leakage measurements and interactions with ventilation flows in low-energy homes

Abstract

Given that airtightness is recognized as an essential issue for low-energy dwellings, today it is often included in energy performance (EP) calculations, frequently through single-zone models with uniform air leakage. Because more consideration is often given to EP than to indoor air quality issues, air leakage through internal partitions is often disregarded. Therefore, additional studies are needed to check these assumptions.In the present study air leakage through the building envelope and through internal partitions is investigated. This paper presents the methodology used in an experimental study, conducted to measure multizone air leakages, using the guarded zone pressurization technique. We developed a detailed innovative database with 456 exterior and internal partition wall air leakage measurements, taken in 23 detached houses. For each wall, the database includes general information on the building, special requirements, the building's main characteristics, measurement protocol, type of wall, measurement input data and measurement results (CL, n, q50 and the reliability index developed). Then an analysis of this database is provided. The analysis reveals most important relationships. For instance, internal partition wall air leakage is not related to the envelope's airtightness level; instead, the type of building structure has greater influence. Through this study, we underline the impact on building airflows of more detailed modelling of internal and external air leakage in multizone approaches, with consequences on indoor air quality (IAQ) bedrooms where people spend most of their time. As a conclusion, we propose air leakage values and dispersion input data for multizone IAQ models.