Assessment of water penetration risk in building facades throughout Brazil

ABSTRACT

The penetration of atmospheric water (rain) into facades creates problems for building habitability and the durability of construction materials. This study analyses the exposure of Brazilian facades to the two main climate factors responsible for this penetration: wind-driven rain and driving rain wind pressure. Daily weather records (spanning 2005–14, from 171 weather stations) were analysed. Both exposure factors were combined to assess the risk of water penetration at each site. The relationships between the different exposure indices calculated from daily, monthly and annual records were determined and compared with results from other countries. From this analysis, detailed isopleth maps are provided that allow a graphical characterization of the moisture exposure conditions of facades anywhere in Brazil. A comprehensive characterization of the water penetration exposure in Brazilian enclosures is created and can be used to establish normative design requirements for actual climatic conditions in each area of the country. In general, an increased risk of penetration was identified in the flat areas of the South and Northeast regions of the country. The sites located in the Amazon basin present comparatively lower risks, despite a greater amount of rainfall, because the wind intensity is less in these inland areas.

KEYWORDS:

• buildings
• climatic conditions
• facade design
• rain
• risk
• water tightness
• wind
• wind-driven rain
• Brazil

Acknowledgments

These results were obtained from data provided by the Instituto Nacional de Meteorologia of Brazil, Ministério da Agricultura, Pecuária e Abastecimento (INMET). The authors thank engineer Diego Lozano Andaluz for his help with data collection and processing.

Additional information

Funding

This work was partially financed by the Spanish Ministry of Science and Innovation co-financed with FEDER funds under Research Project BIA2012-31609.