Spandrel is the panel(s) of a wall located between vision areas of windows, which conceal structural columns floors and shear walls. For spandrel applications Viracon offers Viraspan, a factory-applied, fire-fused ceramic frit paint for use with monolithic or insulating glass and in some laminated glass configurations. A high performance coating on the #2 surface of the laminate is required for units composed with full coverage Viraspan on the #4 surface.
Viracon uses only lead free ceramic frit paints, which are environmentally friendly. A proven performer, Viraspan ceramic frit paints are the product of choice for color consistency, durability, cost control and long life.
Spandrel Glass Applications
The proper application for ceramic fritted spandrel glass is to install it in an opening that has a uniformly colored insulation or back-pan that eliminates the possibility of read-through or viewing the glass in transmission. When done properly, the glass may only be viewed from the exterior of the building, with daylight reflecting from the glass surface
Note: Spandrel Glass is not for vision wall areas
Viracon's ceramic frit spandrel glass products are to be glazed against a uniform, opaque background. We do not recommend that they be used in any application where they can be viewed with daylight or artificial light on the opposite side such as interior partitions, mechanical rooms, screen walls or glazing in a parking garage.
Glass by its nature is highly transparent and it is impossible to make it uniformly opaque. The application of the ceramic frit to the glass surface is achieved by conveying the glass under a rubber application roller. The application of the frit to the glass surface results in striations from the roll that are highly visible when viewing the glass in transmission (with light on the opposite side).
Winter and summer u-values are the performance values available for spandrel glazing. The u-values for spandrel glazing are the same as the corresponding vision unit. Ceramic frit does not affect u-value performance.
Matching Spandrel and Vision Areas
Often a project may require spandrel glass to harmonize with the vision areas of your building. However, this is sometimes difficult to achieve when high-light transmitting or low-reflective glass types are used. Low-light transmitting and high-reflective glass types provide the least contrast between vision and spandrel areas. Variable sky conditions can also influence our perception. On a bright, sunny day, the exterior light intensity is approximately 50 to 100 times greater than the interior lighting level.
When viewing the glass from the outside, the dominant visual characteristic is the exterior reflection. On gray, overcast days, a greater visual disparity is created between vision and spandrel areas due to the transparency of the vision glass and the perception of depth created by interior lighting. The non-vision areas tend to look flat and two-dimensional by contrast. By keeping the vision and spandrel glass construction similar (the same exterior glass color, coating, etc.) the contrast can be minimized under various lighting conditions. Viracon recommends using a neutral colored ceramic frit on the fourth (#4) surface.
Viracon recommends viewing glass samples or full-size mockups to match vision and spandrel glass areas when the visible light transmission of the vision glass exceeds 14 percent.
Moiré is an optical phenomenon that may present itself as a “wavy, rippled or circular” pattern under certain conditions. Moiré patterns can be created whenever one semi-transparent object with a repetitive pattern is placed over another. The moiré pattern is not a glass defect, but rather a pattern in the image formed by the eye. For additional information, please review Viracon’s Moiré Pattern Tech Talk.