The Gallery space is surrounded by exterior walls of glass. The configuration of this space and the resulting amount of glass was by design. The concept for this space and the goals for the building as a whole go back to the Visioning phase of the project.
- Strong physical relationship to the park.
- “Feel” like part of the park.
- Creative use of day-lighting
- Large volume in Gallery
- Views to the park on the southwest side of the project site should be provided wherever possible.
- Allows elevated views from the Visitor Center into the park.
- Eliminates situation where pedestrians at street level on Muskogee Avenue are looking at the roof of the facility.
- The Multipurpose Lobby Area will have a high upward sloping ceiling. Window systems on the north and south side will maximize views through the building and towards the park area to the south.
- Sun Shading will be incorporated on the south of the building by a trellis like structure attached to extended roof beams, providing not only shade but also interesting shadow patterns.
The Visitor Center and to a greater level the design of the Gallery space responded to the client’s vision and goals. They became graphic design solutions through the site studies and preliminary building concepts. There was another goal of the Visitor Center that would further influence the design and selection of the glazing system (glass and framing).
That other goal was to achieve LEED certification. Under the LEED Energy and Atmosphere category, Credit 2 is Optimize Energy Performance. Part of the way in which a high level of energy performance is achieved is through a high-efficiency building envelope. In the Gallery space a significant part of that envelope is glass. So we needed to utilize a high energy-efficient glazing system. This led us to select a triple glass assembly in a thermally isolated frame. We have all heard of double pane glass; well this is triple pane glass which is 3 layers of glass each separated by a gap of air. Various layers of the glass are coated with low E coatings and reflective coatings to enhance the performance.
To give you an idea of energy efficiency here is a comparison of clear double pane glass and the triple pane glass we have specified:
- Double Pane; U value = 2.81, Solar Heat Gain Coefficient = 0.70
- Visitor Center Triple Pane; U value = 0.15, Solar Heat Gain Coefficient = 0.19
We want to slow down the loss of building heat through the windows in the winter time (heat loss) and slow down the transfer of heat into the building in the summer time (heat gain). The U value is basically the heat flow through the glass measured in BTU’s (British Thermal Units) per hour per square foot of glass. The Solar Heat Gain Coefficient (SHGC) is the solar heat gain through the glass relative to the incident of solar radiation; try to wrap you head a round that. Well, I think we will just stick with U values. Anyway, the lower the U value (and also the SHGC) the better. Note the Visitor Center Triple Pane numbers are way lower.
We’ll look at the specifications, performance characteristics and submittals next.