Wind loading on tilted roof-top solar arrays: The parapet effect

Scale model wind tunnel testing was used to investigate the effect of parapets on the wind loading of a roof-top solar array with a tilt angle of 10°. Previous studies have indicated a correlation between parapet height and uplift wind loads acting on roof membranes and roof-top equipment. This relationship was reproduced in the current study for wind loads acting on roof-top solar arrays and is shown to be caused by building-induced aerodynamics, namely corner vortices. Increasing parapet height was shown to increase the peak wind loads acting on the array. These increases were found to be dependent on location on the roof, in the array, and geometry of the array itself. The parapet effect results in peak wind load increases for much of the array for typical parapet heights when all wind directions are considered.