By Nicole Beletsky
Even on clear winter days, the danger of falling ice has snarled rush hour for commuters arriving in Manhattan. The New York Times recently chronicled how the main entrance to the PATH train station at the base of 1 World Trade Center was closed twice in a week because of this risk. New architectural glass contributes to the formation of ice and snow on the façades of tall skyscrapers. The energy efficient glass traps heat in the building but remains cold on the outside, leading to ice formation. The ice eventually detaches and slides down the angled planes of the structure, endangering pedestrians below. The Times also noted that similar ice problems occurred at The New York Times Building in Midtown, and more broadly, on tall structures in Boston, Chicago, Toronto, and Tokyo.
Current building codes focus on wind and snow loads, and energy efficiency standards, rather than addressing hazardous ice and snow accumulation. In fact, a recent 2012 technical paper by Michael Carter and Roman Stangl published in the Council on Tall Buildings and Urban Habitat Journal notes there few guidelines, standards, or building codes exist to address falling or sliding ice and snow. Carter and Stangl highlight how designers have instead ineffectively relied on trial and error or past experience to reduce the potential risk of falling ice. If pedestrians are to quickly and safely walk city streets, it appears that cities need to encourage planners to address this winter weather problem in the design process. How this might be accomplished, by regulation in building codes or otherwise, remains to be seen.
Sources
http://www.nytimes.com/2014/02/12/nyregion/on-the-lookout-for-falling-ice-amid-manhattans-towers.html?_r=2
http://www.ctbuh.org/LinkClick.aspx?fileticket=RQcqzB7ALu0%3D&tabid=53&language=en-US