Improvement of Airtightness for Lightweight Prefabricated Building Envelope through Optimized Design of Panel Joints

Abstract

Airtightness of building envelope is a key factor affecting the indoor comfort, air quality, structural durability and energy efficiency, especially for the lightweight prefabricated building systems aiming to achieve the nearly zero energy goals. For panelised systems, the air mainly leaks through the openings and panel joints. However, most current studies concentrate on the airtightness of the former ones, such as windows and doors, studies on joint design are relatively rare. As a result, this study firstly proposes two joint prototypes, the straight joints and the special-shaped joints, with various design parameters. Secondly, the air infiltration volume for different joints are simulated and calculated by the CFD method. Besides, the volume was further compared to find out the optimized joint design. Finally, the airtightness requirements of Passivhaus are used to evaluate the performance of the optimized tongue and groove joint with the conventional straight ones. The results prove that the well-designed joints deliver better airtightness especially for the high-performance standard buildings.