'Tis the season for thermal stress

摘要

In our northern climates, where temperatures can plummet to -30 C and colder, consumers can see an increase in glass breakage in their windows. This year in the Ottawa area, an unprecedented number of glass breakages have been reported with temperatures in the -39 C range with intense sun for days on end. It's a chilly time. One of the common factors that can lead to breakage of annealed glass used in insulating glass units is thermal stress. How do you identify a thermal stress break from other types of glass breakage? Thermal stress breaks start at 90 degrees (perpendicular) to the glass edge. Depending on the degree of thermal stress, the crack may be a single break or a branch off in multiple directions. It all depends on how much stress needs to be relieved.