An Analysis of ACHn for Improving the Performance of Green Remodeling through the Airtightness Measurements

Abstract

Purpose: The study analyzed the airtightness of several buildings which were constructed more than 30, 20, 10 years ago and recently constructed by using various air leakage metrics. In addition, the various ACHn values were estimated in which it is not possible to maintain the reference pressure difference of 50 Pa due to some building conditions such as aged or large volume. Moreover, the relationship between the values of ACH 50 and ACHn was analyzed. Method: Two rooms in four different buildings were chosen and the air leakage rates were measured by using the fan-pressurization method based on ISO Standard 9972. For the measurement, both pressurization and depressurization test modes were applied twice. Various airtightness metrics were analyzed for the air leakages in each room. Result: The biggest air leakages were observed in the oldest building in which the ACH50 value was 24.35 h<SUP>-1</SUP>. Similar air permeability values were observed between the rooms in the buildings. Therefore, this metric can be used as a representative air leakage rate for the whole building. Moreover, the conversion coefficient for the ACHn values at different pressures from 4 Pa to 75 Pa based on the ACH50 value was estimated.