Wind-driven rain and its impact on building envelopes

建筑围护结构抵抗气候负荷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/正能源状态的程度。建筑围护结构的失效占建筑失效的50%以上。雨水和径流带来的湿气侵入是导致许多建筑围护结构失效的主要湿气来源，并且经常导致昂贵的维修，例如温哥华漏水的公寓。建筑围护结构管理水分的能力，特别是风驱雨（WDR）和雨水渗透的能力，决定了它的长期耐久性。本研究的目标是促进对水荷载和径流荷载及其对建筑围护结构的影响的理解，开发设计工具，并制定设计指南，以提供具有长期耐久性的节能建筑围护结构。拟议的研究将有助于巩固关于受WDR和雨水径流影响的建筑围护结构系统的湿热性能的知识体系，通过i)调查加拿大三个不同地理区域的WDR负荷和由此产生的建筑围护结构径流，（ii）检查悬垂在减少建筑立面上的WDR量方面的作用，以及（iii）调查风力驱动的雨水对高度隔热墙组件的湿热响应的影响。拟议的研究涉及实验室和现场测量之间的平衡，以及建模和模拟。该方法将包括：i)通过现场测量和CFD建模来量化悬垂对减少建筑立面WDR的有效性；Ii)通过实验室和实地测量和建模，建立建筑物表面的雨水径流；Iii)开发一种随机方法来模拟墙体组件的湿热响应，iv)通过推广本研究获得的结果，开发一种设计工具来管理高度绝缘墙体组件的湿气损害风险。拟议的研究项目将通过提供高性能建筑围护结构的设计工具和指导方针，促进对水荷载和径流作为设计负荷和最佳实践的基本理解。为设计师提供指南和工具，以更好地评估WDR负载和耐久性风险，将使他们能够在众多被普遍接受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，特别是在更高的能源效率需求下。确保节能建筑围护结构的长期耐用性将有助于加拿大减少温室气体排放的国家目标。这项研究将为培训hqp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.