Late-emerging Defects with Insulating Glazing Units

摘要

To meet performance demands for energy conservation, noise resistance, heat gain, and indoor comfort, designers often specify insulating glazing units (IGUs). Annealed, heat strengthened, and tempered glass are produced by suppliers and shipped to fabricators for assembly, to meet specified design criteria. Typically, two or more glass panes are assembled with an air space, perimeter spacer desiccant, a primary seal to prevent vapor transmission, and a secondary seal to provide structural integrity. To increase strength, multilayer laminated glass may replace monolithic sheets. Coating the surfaces adjacent to the interior air space and incorporating argon gas can improve thermal performance. With so many components, IGUs are susceptible to defects originating throughout the design, installation, manufacturing, and fabrication process. Often, problems related to manufacturing and fabrication are not noticeable until after the unit has been installed, with some defects not apparent until well after the windows are in service.