Available online 16 January 2013
Publication year: 2013
Source:Building and Environment
A critical review on boundary conditions for watertightness testing was presented in a related paper forming Part I of “A uniform methodology to establish test parameters for watertightness testing”. Existing methodologies to establish test conditions only partially consider co-occurrence of rain and wind, which yields large uncertainties when determining return periods for extreme wind-driven rain events. This paper presents a new approach based on a Pareto fronts method for which wind driven rain intensities and wind pressures are derived. Straight lines can be fitted to consecutive fronts, and a generalised Pareto distribution describes the corresponding probabilities of occurrence of wind-driven rain events. Assumptions in the use of the methods are given and constraints to its use provided by means of case-studies. Advantages over existing methods for estimating watertightness test parameters are highlighted. Test conditions can be calculated for various configurations and different averaging periods depending on the failure behaviour of specific building envelop components. Subsequently it is shown that the conversion of case-based test conditions to generic test protocols and performance levels requires careful consideration. Finally, the paper provides practical guidelines on defining realistic watertightness performance levels for building envelop components.
► Co-occurrence of rain and wind is evaluated by means of Pareto front analysis. ► A Pareto distribution allows to determine the probability of extreme WDR events. ► Based on case-studies, large discrepancies with existing methods were found. ► Guidelines on the conversion towards generic performance levels are reported.
Publication year: 2013
Source:Building and Environment