Airtightness, pressure differences and indoor climate in the experimental building Kasarminkatu 24.

Reports on pressure tests carried out on the Kasarminkatu 24 building (a museum of architecture) in Helsinki. The fans in the building were used to measure airtightness of the building envelope, and the tightness of windows and doors was measured separately by the guarded box method. The tightness of the building envelope was good (2 ach at 50 Pa). 70% of total air leakage came through the wooden roof structure, and only 5-10% through the windowstructure. Three alternative mechanical ventilation systems were also studied in the same building to assess their impact on indoor climate.