Insulating glass (IG) units—or IGUs—have come a long way in the past 70 years. Originally mass-produced in the early 1940s to decrease noise and increase passenger comfort in Pullman railroad cars, the technology has transcended that mobile application.
Window walls eventually fail under repeated occurrences of causes like loads, movement, stress fatigue, and the degradation of material properties due to aging. How can one simply anticipate the ‘causes’ and then design to eliminate them in the first place?
In the December 2014 issue of The Construction Specifier, Dean Lewis wrote about the North American Fenestration Standard/Specification for Windows, Doors, and Skylights’s (NAFS’) short-form specification. American Architectural Manufacturers Association/Window and Door Manufacturers Association/Canadian Standards Association (AAMA/WDMA/CSA) 101/I.S. 2/A440, serves as the basis for product certification as required by the International Building Code (IBC).
Cracking was observed in the exterior curtain wall glass on an early-1970s mid-rise building in the Midwest. As originally constructed, the curtain wall included single-glazed 5.5-mm (7/32-in.) thick bronze-tinted glass at all floors—except the uppermost level, which featured single-glazed 9.5-mm (3/8-in.) thick clear polished plate glass.