Review of wind effect on measurement of building airtightness

A dramatic rise in the global energy demand has been noted, with its growth coming from the emerging economies, higher living standard and comfort levels. Research shows that building infiltration could account for 30-50% of energy consumption for space heating, including ventilation in a leaky house (i.e.10ach at 50Pa). Building airtightness is regarded as the fundamental building property that impacts infiltration and exfiltration, and is a crucial factor to be concerned with in order to improve the energy performance of buildings. The influence of poor airtightness on the built environment has brought about wide concern since the 1970s, citing negative impacts on building energy consumption, building durability, indoor air quality and noise transmission. Generally, the common method to quantify the building airtightness is implemented by pressurising or depressurising the building to achieve a pressure difference between the inside and the outside of the building and record the corresponding airflow rate. At present, the blower door is the most popular approach, and the Pulse technique is another promising technology for building airtightness measurement. Extensive studies on building airtightness measurements have been conducted using blower door and Pulse technique, and researchers have pointed out that the uncertainty of measurement could be caused by various factors under different weather conditions. In this study, a comprehensive review of the literature is presented regarding the wind effect on building airtightness measurement. The review indicates that limited investigations have been carried out to clarify the effect of unsteady wind condition on the building airtightness measurement both through blower door and Pulse testing and to provide a precise assessment of building airtightness under variable wind conditions. Requirements on the testing weather condition have been set in the national and international standards for fan pressurisation method to determine building airtightness. However, the wind speed limits for different national standards vary, which also indicates the necessity of defining more practical wind speed limit for building airtightness measurement. On the other hand, as no regulations for the Pulse testing have been found in the standards, there is a need of protocols that can be used to characterise building airtightness measurement for the Pulse technique.