Airtightness of Nepalese Residential Buildings

Experimental field measurements regarding airtightness following the fan pressurisation method were done on 25 typical residential buildings at different locations in Nepal. The field measurement data were classified according to building type and building age. The mean air permeability (Q50 ) for the studied buildings was 6.9 l/s·m2 and the mean air change rate was 55.5 air changes per hour at 50 Pa. The maximum air leakage rate (Q50 ) was 28.4 l/s·m2 for brick masonry in mud mortar type and the minimum recorded was 1.7 l/s·m2 for brick masonry in cement mortar type building. Brick masonry in mud mortar-type buildings was found to be leakier regardless of the building age, and brick masonry in cement mortar-type buildings was comparatively more airtight. Leakage locations identified through visual inspection included the spacing between the door frame and operable door area, horizontal window slider, joint areas of window frame and wall, wood plank-based wall structure, roof joint areas and holes in the wall. This research is the first of its kind in Nepal to assess the airtightness of buildings, and the outcome of this research is one of the key parameters to evaluate the thermal performance of Nepalese buildings scientifically.