Procedure for a detailed territorial assessment of wind-driven rain and driving-rain wind pressure and its implementation to three Spanish regions

• Analysis of climate data from 393 weather stations placed in three Spanish regions.
• Procedure to estimate driving rain and wind pressure by combining different data.
• Development of detailed isopleth regional maps to characterise these exposures.
• Calculation of a risk index of water penetration in building façades.
• Creation of water penetration risk maps for Galicia, Catalonia and Andalusia.

Wind-driven rain and the simultaneous action of wind pressure contribute to water penetration into building façades. Therefore, both climatic parameters must be considered in the design of building enclosures to manage the effects of water intrusion. This article presents a procedure for determining both parameters in a geographic area, by combining various data sources. The procedure was implemented in three Spanish regions with different climates (Galicia, Catalonia and Andalusia), by combining precipitation and wind velocity records compiled at 393 weather stations distributed across these regions, using wind maps, and fitting relationships between exposure indices. In comparison to other studies, this procedure allows for data from a relatively large number of locations to be included in the exposure assessment, which can produce a more detailed characterisation across the territory and facilitate the creation of isopleth exposure maps. A risk index of water penetration, which combines the influence of both exposures, was also calculated. The results showed that the exposure of building façades to water penetration was driven by the climate of each zone. Galicia is the most exposed region. Moreover, the Strait of Gibraltar and Gulf of Cadiz in Andalusia and the Cape of Creus in Catalonia are also zones of high exposure.