Wind-driven rain and its impact on building envelopes

建筑围护结构抵抗气候荷载的有效性决定了建筑的性能和耐久性、能源消耗以及实现净零/零+能源状态的程度。围护结构破坏占建筑物破坏的50%以上。风引起的雨水和径流造成的湿气侵入是导致许多建筑围护结构故障的主要湿气来源，而且经常导致昂贵的维修费用，例如温哥华漏水公寓的情况。建筑围护结构管理水分的能力，特别是风力驱动的雨水(WDR)和雨水渗透，决定了它的长期耐用性。**这项研究的目标是促进对WDR和径流负荷及其对建筑围护结构的影响的了解，开发设计工具，并为提供具有长期耐用性的节能建筑围护结构制定设计指南。拟议的研究将通过以下方式巩固有关建筑围护结构系统湿热性能的知识：i)调查加拿大三个不同地理区域的建筑围护结构的水热负荷和由此产生的径流；(Ii)研究悬挑对减少建筑外墙表面的水热负荷的作用；以及(Iii)调查风致降雨对高度隔热墙体组件的湿热反应的影响。**拟议的研究涉及实验室和现场测量以及建模和模拟之间的平衡。该方法将包括：i)通过现场测量和CFD建模，量化悬挑对减少建筑外墙WDR的有效性；ii)通过实验室和现场测量和建模，建立建筑外墙的雨水径流；iii)开发一种随机方法来模拟墙体组件的湿热响应；以及iv)通过推广本研究的结果，开发一种设计工具，用于管理高度隔热墙体组件的湿气损害风险。**拟议的研究计划将通过提供高性能建筑围护结构的设计工具和指南，促进对WDR和径流作为设计负荷和最佳实践的基本理解。为设计师提供更好地评估WDR荷载和耐久性风险的指南和工具，将使他们能够在众多通常被视为最佳实践的墙体组件中做出更明智的选择，从而提高建筑设计的一致性和可靠性，特别是在满足更高能效要求的情况下。确保高能效建筑围护结构的长期耐用性将有助于加拿大实现减少温室气体排放的国家目标。这项研究将为HQP的培训提供极好的机会。

The effectiveness of the building envelope to resist climatic loads determines the performance and durability of the building, its energy consumption, and the extent to which its net-zero/plus energy status can be achieved. Failures in building envelopes account for over 50% of building failures. Moisture intrusion by wind-driven rain and runoffs is the major source of moisture causing many building envelope failures, and often results in costly repairs, such as the case with Vancouver leaky condominium. The building envelope's capacity to manage moisture, especially wind-driven rain (WDR) and rain penetration, determines its long-term durability. **The goal of this research is to advance the understanding of WDR and runoff loads and their impact on building envelopes, to develop design tools, and to generate design guidelines for delivering energy efficient building envelopes with long-term durability. The proposed research will help consolidate a body of knowledge on the hygrothermal performance of building envelope systems subjected to WDR and rainwater runoff by i) investigating the WDR load and resulting runoffs on building envelopes in three different geographic regions in Canada, (ii) examining the role of overhangs on reducing the amount of WDR on building façades, and (iii) investigating the impact of wind-driven rain on the hygrothermal response of highly insulated wall assemblies. **The proposed research involves a balance between laboratory and field measurements, and modeling and simulations. The methodology will include: i) quantifying the effectiveness of overhangs on reducing WDR on building façades through field measurements and CFD modeling; ii) establishing rainwater runoff on building façades through laboratory and field measurements, and modeling; iii) developing a stochastic approach to model the hygrothermal responses of wall assemblies, and iv) developing a design tool for managing moisture damage risks in highly insulated wall assemblies by generalizing the results obtained in this study. **The proposed research program will advance the fundamental understanding of WDR and runoff as design loads and best practices by providing design tools and guidelines for delivering high performance building envelopes. Providing designers with guidelines and tools to better assess WDR loads and durability risks will enable them to make more informed choices among the numerous wall assemblies commonly accepted as best practices, resulting in improved consistency and reliability of building designs, especially with the higher energy efficiency demand. Ensuring long-term durability of energy efficient building envelopes will contribute to Canada's national objectives for the reduction of GHG emissions. This research will provide excellent opportunities to train HQPs.