Mark Meshulam is an expert witness and consultant for low-e glass and architectural glass.
Bob Carlson is a Field Sales Representative for Viracon a premium producer of fabricated and coated architectural glass. He is known in our market as a valuable informational resource. He’s a very nice guy, too. Bob’s territory is Illinois and Wisconsin
Q: What can you tell us that will help put the array of Low-E glass choices into an understandable framework?
Viracon: I think itâ€™s helpful to start by understanding the history. Back in the 1970s and 1980s we used glass with a mirrored exterior. They are not used now because they reduced visible light down to 8-15% and also created an unpleasant mirrored look on the interior when it was dark outside.
This obsolete category used our designations VS (stainless steel), VT (titanium) and VA (antique). The most popular orf this family was VS114. It has visible light at 12%, exterior reflectance at 33% and interior reflectance at 38%. The good news was the solar heat gain was only .18, as compared with 1.0 if no glass was present at all.
Then we evolved the Viracon Solarscreen family of products. These work to achieve a better balance between visible light and solar energy, and interior reflectance is acceptable. These designations are VE (low-e) and VNE (neutral low-e).
VE1-40 (The 40 is nominal visible light)
VE1-2M Our most popular with high visible light
VNE 1-63 This is similar to Solarban 70 triple silver.
The Blue Cross building in Chicago uses our VE152. It is clear glass with a bluish coating.
Our next family is VRE, the Viracon Radiant Coating. You can see VRE 1-59 on Trump Tower in Chicago. It is more reflective to the exterior yet keeps the interior reflectance low, to avoid that interior mirror look. Take a look at the chart below for a good overview of some distinctly different product types:
Q: How do you compare the market position of Viracon with that of PPG and Guardian?
Viracon: PPG and Guardian are primary glass manufacturers and Viracon is a fabricator. PPG and Guardian make float glass in clear or color, then coat it and send it to other fabricators for cutting and insulating. Viracon is a fabricator, and we apply coatings to primary glass which we buy from primary manufacturers. The ability to temper and coat glass in house changes the sequence of manufacturing. If tempering or heat treating is needed, typically that process will follow the coating process if produced by PPG or Guardian. On the other hand, we temper first, then coat the glass. We feel that we get better flatness that way.
Q: Is Viracon company involved in self-heating glass, glass that warms itself with the application of electricity?
Viracon: Any low-e coating will conduct electricity because it is metal. However, we are not moving into self-heating glass at this time.
We did quite a bit of research on electrochromic glass â€“ glass that can darken or lighten itself. The technology has been spun off to Sage Electrochromics. I think the maximum size for this is 3â€™ x 3â€™.
Another interesting technology we helped develop is the use of holograms embedded in the laminated glass interlayer. We think someday the light trapped in this interlayer can be brought into the building through the use of fiber optics. We donated this technology to the University of Arizona. (See a related project here: http://uanews.org/node/26541)
Q: What trends do you see for the future?
Viracon: There is an increasing awareness that in commercial buildings, 40-50% of building energy is consumed by producing light, or removing the heat produced by those lights. We see architects increasingly move toward ways to bring more outside light into the buildingâ€™s interior, for instance, with the use of â€œlight shelvesâ€. For our part, we produce the glass that can help meet these goals.
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