Large and complex structures benefit from detailed knowledge of wind impacts regarding the design of cladding and structural systems. In many modern structures, incorporating complex geometries and long spans, determination of cladding pressures is an essential component of the design process. For many projects cladding studies result in economic savings over designs based on local building codes.

Cladding pressures are determined most accurately by wind tunnel testing of a physical scale model of the study building placed among its surroundings. In typical fashion, the model is instrumented with a large number of pressure measuring locations, referred to as pressure taps. Measurements are performed simultaneously at many locations using a high-speed scanning system sampling at a rate of 500 samples per second. Results are obtained for winds approaching the site from the entire 360-degree azimuth at intervals of 10-degrees. Data from wind tunnel testing is converted to full scale and combined with the meteorological statistics for the site to obtain predicted wind pressures for desired return periods.

Wind forces on roofs can be highly turbulent due to the geometry of the roof and influence of surrounding buildings. Accurate knowledge of the local wind forces may be critical to performance of roof cladding and roofing system selected to enclose the building. Furthermore, knowledge of the wind regime over a roof is essential for design of ‘green’ roofs which are part of growing sustainability initiatives in the architectural community.