Wind load is the result of wind creating pressure that the glass must resist. The wind load on a specific building depends on that building’s height, shape, relationship to surrounding buildings and terrain, along with local wind speeds and the duration of gusts. Wind loads can damage architectural glass. The key to prevention comes early in the design stage.
Center deflection is a major consideration in wind load and should be addressed in the early phases of design. Excessive center deflection can result in edge pull out, distortion of reflected images and possible contact between glass and interior components, such as room dividers and window blinds.
The effects of wind on insulating glass units are, in many cases, complex and require a computer-assisted wind load analysis to adequately consider some of the variables. Design professionals must take into account the following variables:
- Air space expansion and contraction caused by the effects of changing temperatures, barometric pressure, altitude and differences in weathering in surface 1 and surface 2
- Asymmetrical loading, i.e., lites of varying thickness
- Load-sharing other than 50-50
- Condition of edges (free or fixed)
- Variation in sight line or air space width
- Thermal stress
These variables must be considered carefully because they can dramatically alter the data taken from a standard wind load chart.
Guardian follows the current ASTM E 1300 “Standard Practice for Determining the Minimum Thickness and Type of Glass Required to Resist a Specified Load.” This information represents in-service glass and supersedes the traditional straight-line graph as well as other wind load charts.
The ASTM wind load standard is applicable to projects built in the United States. Wind load standards for other countries may differ, and this difference must be addressed in the early stages of design.
Contact us for assistance with wind load analysis.