| Abstract | An experimental setup was designed to test the effect of water deposition rate and pressure difference on the ingress of water through deficiencies. A number of round deficiencies (1mm, 4mm and 8mm diameter) were installed in a vertical polycarbonate plate, and subjected to a range of pressure differences (0, 200, 400, 600, 800Pa) and two water spray rates which are typically used in watertightness testing (2.0 and 3.4 L/min.m²). The infiltration rate was measured accurately by means of level sensors in collection troughs. This paper describes the phenomenology of the processes that govern the infiltration of water, and discusses the balance of forces that act on the water at the deficiency. The surface tension of the meniscus on the interior side of the deficiency (minus the capillary and hydrostatic pressure) defines a threshold pressure difference before infiltration will occur. The measurements confirmed the expected processes, but the pressure threshold levels for infiltration to occur supersede the calculated pressure levels. For each water spray rate the infiltration rates could be fitted to a power law, which indicates that the runoff pattern cannot be quantified as a constant hydrostatic water column. |
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