Predicting environmental conditions at building site for Natural ventilation design: Correlation of meteorological data to air speed at building openings

For the design of naturally ventilated buildings, information of air speed at the openings of a building is important. However, the only data set usually available to designers is meteorological data, such as wind speed and direction measured at weather stations. This paper explores the ratio of air speed at building openings to the wind speed measured at weather stations. Meteorological data from three weather stations as well as air velocity that was obtained through full-scale physical measurements were used in this study. The results showed that air speed at building openings was about half of the wind speed recorded at the closest station to the case study. This ratio reduced to approximately 30% when comparing to the weather stations located in greater distance and more open areas. Given that air speed at the openings has a direct relation to the ventilation rate, employing these ratios to the available weather data when designing for natural ventilation, can provide more realistic picture of natural ventilation performance.