Measurement and analysis of airtightness safeguard measures for typical ultra-low energy buildings

•Analyzed the causes for typical air leakage paths in buildings.•Targeted airtightness safeguard measures were proposed and verified.•New grading index for public buildings was suggested. Zero-energy buildings constitute an effective means of reducing urban carbon emissions. High airtightness, a typical characteristic of zero-energy building, is closely related to the building's air infiltration and has a significant impact on the performance of the building envelope, indoor air quality, building energy consumption, and efficient operation of air-conditioning systems. However, thus far, systematic developments in high-airtightness assurance technologies remain scarce. Most existing studies have tested the airtightness of buildings and typical building components; however, in-depth analyses into the formation of infiltration have not been reported. Therefore, for realizing zero-energy buildings, ensuring airtightness is an urgent problem that needs to be addressed. Accordingly, in this study, based on several building airtightness measurement studies, the typical air leakage paths in buildings were summarized, and the causes of typical air leakage components in buildings were further analysed by tracing construction processes. Moreover, targeted measures for airtightness in buildings were established and applied to practical cases. Lastly, the resulting improved building airtightness was measured and the results show that the airtightness of the measured ultra-low energy consumption buildings ranges from 0.13 h−1 to 0.57 h−1, with a mean value of 0.32 h−1. The effectiveness of the airtightness safeguard measures was verified. This study serves as a basis for the assumption of the air leakage path distribution when simulating building air infiltration and also provides a design reference for improving the construction technologies and airtightness of buildings. [Display omitted]