Experimental Analysis of Airtightness Performance in Modular Elementary School Buildings

Purpose: This study analyzed the airtightness of modular elementary school buildings in South Korea. Modular buildings are typically constructed on-site using various prefabricated modules (walls, floors, roof, and structural frames). In South Korea, these buildings are frequently used temporarily during school remodeling or expansion, and more recently, they are being adopted as permanent facilities due to population shifts. However, air infiltration through joints between modules has been a recurring issue, leading to poor indoor air quality and increased heating/cooling energy consumption. Thus, it was important to accurately determine the infiltration rates through these gaps. Method: In this study, air infiltration rates were measured using standardized blower door tests in two modular elementary school buildings located in South Korea. The test procedure followed recommended guidelines for pressurization and depressurization, and the results were expressed as air changes per hour at 50 Pa (ACH50). Results: The measured infiltration rates ranged from approximately 5 to 31 ACH50 in the two modular elementary school buildings. Notably, the highest infiltration was consistently observed through the gaps of entrance doors, indicating that door assemblies represented the weakest point in modular classroom airtightness.