Finnish design ventilation rates for residential buildings

Abstract

Implementation of EU directives has forced EU member countries to revise the building regulations related energy efficiency. The 2017 revision of the building codes is due to the requirement set in the EPBD 2010 for all new buildings to be nearly zero buildings by 2020. The Finnish Ministry of the Environment (in charge of building regulations) invited FINVAC Federation of Finnish HVAC Associations to revise the guidelines values of ventilation rates as part of the nearly zero energy building regulations. At the same time, the Finnish Society of Indoor Air Quality and Climate updated its voluntary Classification of Indoor Environment. Several methods were used in the study to collect information and develop the new guideline values. European studies, such as HEALTHVENT, and relevant CEN standards were taken into consideration in drafting the design ventilation rates. Existing legislation on housing conditions gave the minimum levels and, finally, the recommended values were defined using expert interviews, workshops and public review process. Earlier studies had indicated that earlier design ventilation rates were too high for small apartments. Ventilation rates were considered too low for homes of elderly people and residential kitchen hoods, and some larger apartments. Furthermore, the balance of outdoor and exhaust air flows needed revision due to the improved tightness of the building envelope. Energy efficiency and avoidance of draught and noise were also taken into account. This paper presents the numeric values of the ventilation rates in the new building regulations and the design guidelines supporting them.