Conservation labs usually focus on assessing the nature and condition of historic fabric made of historic materials and finishes such as stone, fired clays, plaster, ferrous metals, copper, bronzes and other alloys. But not glass. That's exactly on what AYON Studio Principal Angel Ayón focused when discussing glass and glazing to Historic Preservation students at Columbia University's Preservation Technology Lab. Part of Francoise Bollack's seminar titled Old Buildings – New Energy: History and Sustainable Practices, the program included a lecture followed by a lab session.
After presenting the findings of his research on conservation of Modern glazed enclosures included in his book on Reglazing Modernism, Ayón guided the students through understanding and evaluating visual properties of different types of glass, including clear, ultra-clear / low-iron, tinted, and low-e coated glass. Thermal performance was evaluated by measuring heat flow (energy loss/gain through transmission, radiation, etc.) through electronic heat flux sensors connected to different glass assemblies such as single-pane, insulated glass units (IGU) and vacuum insulated glazing (VIG).
The lab session allowed the students to think of glass as a man-made material and glazing as a construction assembly whose visual and performance characteristics (u-value, weight and thickness, SHGC, etc.) are relevant considerations to be taken into account during reglazing interventions. For more on Reglazing Modernism, see https://www.ayonstudio.com/book.