Load Sharing and Spacer Flexibility in Double Pane and Triple Pane Insulating Glass Units

Abstract

Insulating glass (IG) is comprised of two plates of glass that lie close to one another without touching. The plates are separated by a sealed gas space that consists of a spacer material that surrounds the perimeter of each plate. This spacer does not allow gas flow into or out of the IG unit. IG must consist of at least two plates of glass, but can be expanded to three plates of glass where there would be two sealed gas spaces. As a result of the configuration of IG units, the load that is distributed between the plates will vary based on the properties of the glass, the initial conditions of the unit, and the properties of the spacer material.

It has long been understood that the load sharing between double pane IG units can be influenced by different factors in the unit. These factors include the thickness of the plates, temperature variations in the sealed gas space, and atmospheric pressure differences between the sealed gas space and the current atmospheric pressure.

Computer software was used to write a program that accurately modeled existing experimental data on tests completed for double pane IG units. When accurate results were obtained, a portion of the research was used to focus on flexibility in the spacer material transferring a portion of the load through the unit. A triple pane IG model was developed to evaluate the effects of extreme pressure drops in a hurricane as well as gas space temperature variations. Spacer flexibility was incorporated into this model to see its influence on load sharing between the plates of glass. The triple pane IG unit’s plates were sized and then analyzed to see how the pressure drop and temperature variation influenced the original design.