Fast Estimation of Leakage Area in a Multizone Test Facility

The effects of building leakage on heat and mass transfer in buildings are difficult to model due to the difficulty in knowing crack size, shape, position, and number. Nevertheless, interest remains high in the estimation of crack areas in buildings because of the important effects cracks have on infiltration, indoor air quality, building energy performance, and because of interest in exploring mitigation/ventilation strategies. We show how a steady-state model is developed that can provide fast estimation of the crack areas for a test facility. The facility is then modeled in CONTAM to perform simulations and make prediction of overpressure values using the set of estimated crack areas determined from the above model. Comparisons are made between the CONTAM model predictions and experimental results in terms of overpressure, and good agreement is achieved. The experimental overpressure ranges from 3 Pa to 155 Pa, covering the normal range of overpressure in commercial and residential buildings. The method outlined in the present work can be extended to estimate crack areas of the openings in multizone pressurization tests. Further, this method holds promise in filling the knowledge gap of interzonal leakage in multizone buildings.