Comparative Assessment of International Standards for Curtain Wall Structural Design

In the last two decades, there has been a significant increase in the use of building façades in mid- to high-rise buildings. These façades are made up of various materials including glass, sheet metal, vinyl, timber, and aluminum. In particular, curtain walls, which are essentially multilayered glass infills within aluminum frames, are used for residential, health care, and mixed-use buildings due to their esthetic appeal. In the last decade, an increase in the number of extreme weather events, such as tornadoes, hurricanes, tsunamis, and typhoons, has resulted in several wind-induced damages to these curtain wall systems, in addition to a few reported seismically induced failures. Therefore, it is necessary to compare the available standards and assess their adequacy in curtain wall design. The first part of this paper discusses the available standards developed by the ASTM that provide testing procedures for building façade systems, including curtain walls for wind, impact, water penetration, air tightness, and thermal and sound transmission. The second part of this paper compares the standards developed in United States, Canada, Australia, and Europe in estimating the relevant structural design parameters for glass of various sizes and configurations. Results show that the Australian standard predicts the highest load resistance (LR) for annealed glass compared to other standards. The American standard predicts higher LR compared to other standards for fully tempered glass. Moreover, the Australian, American, Canadian, and European standards yield decrease in predictions of LR values of 65%, 69%, 78%, and 81%, respectively, compared to experimental results, stemming from the probabilistic approaches embraced by these standards. These standards employ varying probabilistic approaches to predict the LR. Future work dedicated toward correct implementation of current ASTM testing standards and improvements in probability-based design of glass design standards is necessary to prevent curtain wall damage due to environmental loads.