Assessment of Wind Impact on Building Air Leakage Measurements using a Model Scale Experiment

Nowadays, many countries include requirements for building airtightness in their current national regulations or energy-efficiency programs, mainly for concern about reducing building energy consumption due to air leakage. Moreover, some countries impose a mandatory justification with an air leakage measurement. Therefore, the uncertainty of the measurement results has become a key concern in several countries over the past year. More specifically, the influence of wind speed has been identified as one of the major sources of error on the measurement result.
The goal of our work is to improve uncertainty estimates and test protocols starting from model scale experiments in controlled laboratory conditions. We first present the experimental facility we developed to perform pressurization tests at model scale, which includes: 1- a model at 1/25th, 2- a pressurization device that pressurizes the model up to 100 Pa and 3- a wind tunnel in which the wind is stable from 0 to 7 m s-1. Secondly, we present the zero-flow pressure measurement results for 9 leakage distributions and 8 wind speeds: these results strongly depends on the leakage disbritbution, with an abdsolute value of zero-flow pressure difference that varies for strong winds from 1 Pa to more than 16 Pa. Finally, we calculate the error due to steady wind from 96 tests performed according to ISO 9972 in various wind conditions and for the 9 leakage distributions. At 4 Pa, the maximal error varies from 2% to 35%.