Avoiding the need to directionally determine the exposure to rainwater penetration for façade designs.

The damaging effects caused by the penetration of rainwater into building façades require considering for their design the exposure to the two main climatic factors inducing this penetration: wind-driven rain and the simultaneous wind pressure. The characterisation of these exposures for each possible façade orientation of a building requires analysing exhaustive wind direction records, which significantly increases the calculation effort and prevents calculation in locations without such records. This study examines the possibility to avoid this directional analysis, equally obtaining a functional and reliable exposure characterisation. For this purpose, daily climatic datasets were analysed from 920 weather stations subjected to various environmental and topographic conditions in Mexico, Norway and Spain, and the directional and scalar exposures to wind-driven rain and driving-rain wind pressure were determined at each location. The results show that the maximum directional exposure can be adequately approximated using the scalar exposure value, without the use of wind direction records. Considering the usual constructive practice of using a single façade design for the entire building, this simple and functional characterisation of the expected exposure on the most unfavourable orientation provides a significant support for the design decisions of practitioners. • Analysis of wind-driven rain and simultaneous wind pressure in 920 sites. • Correlation between scalar exposures and maximum directional exposures by location. • Functional extrapolation of maximum directional exposure from a simple scalar value. • Influence of climatic and dataset time resolution factors over correlation validity. • Reduction of calculation effort and analysis of sites with limited climatic data. [ABSTRACT FROM AUTHOR]