Internal pressures – The dominant windward opening case – A review

A building with a dominant opening in a wall may experience internal pressures equal to, or greater than, the external wind pressures in a severe windstorm. This is a critical design case in severe wind events, during which accidental openings may be produced by windborne debris or by direct wind loading. This paper reviews previous work on the prediction of fluctuating and peak internal pressures arising from a dominant opening on a windward wall, and summarizes proposed, or current, code formulations in a unified non-dimensional format. Experimental data from a number of sources are plotted together, and are found to fall into two groups, depending on the turbulence intensity in the approach flow. It is shown that the proposed relationships for the ratio of internal to external pressure fluctuations differ considerably, depending on the assumptions made. An intermediate relationship, which agrees well with experimental data in approach flow with turbulence intensities representative of atmospheric wind flow in developed boundary layers, is presented, and a design example of its application is given. ► Ratios of internal to external pressure fluctuations are shown in a common non-dimensional format. ► The effect of upwind turbulence intensity on Helmholtz resonance effects. ► A practical design relationship for the ratio of peak internal to peak external pressures.