Art, science and endless possibilities
Finsbury Avenue Square, adjacent to Liverpool Street Station in London, features a $2.8 million architectural installation using Super Spacer TriSeal in double-glazed lighting units covering a 215-square-foot lattice.
In the early days, windows were strictly utilitarian, letting a little light in and some fresh air on a nice day. They have also been the nemesis of energy efficiency because they provide openings that enable heat and energy to transfer. Daylight openings are well known as the weakest link in the building envelope then and now.
Fortunately for all of us, fenestration technology has made significant advances with high performance coatings, spacer material, framing and other enhancements. Commercial architects now have the flexibility – literally – to get creative with their building designs and energy savings. The advent of warm edge technology and high performance coatings brought about a new world of possibilities for using insulating glass and made creative daylighting possible without sacrificing the structural integrity and the energy efficiency of the building envelope.
Stainless steel warm edge spacer systems provided improvements in energy efficiency compared to their highly-conductive aluminum predecessors, making them suitable for large curtain wall systems. However, problems still remained. First, while providing improvements in thermal conductivity, stainless steel is still quite conductive – which means the spacer facilitates heat transfer and condensation is more likely to occur. Also, stainless steel does not easily bend for special shapes and applications.
The development of high-performance, flexible warm edge spacer systems address all of these concerns, and more. With today’s advanced foam spacer technologies it is possible to achieve:
• Optimal U-values (rate of heat transfer) and condensation resistance to meet code and LEED requirements.
• Wind load resistances up to 155 psf (or 246 mph), even in silicone structural glazed curtain wall systems to continue satisfying the heavy commercial market demands.
• Flexibility to produce shapes and specialty glass applications including complex bent glass designs.
It is important to remember though that not all warm edge or even flexible warm edge technologies are created equal. Flexible spacer options include butyl-based thermoplastics and structural foam constructions. However, just because the spacer system is flexible does not make it durable. Structural foam systems have proven themselves in a wide range of commercial applications that involved expensive glass options. With the increased liability costs of these glass projects, the spacer selection was crucial.
Case studies in innovation
Flexible foam spacer technology has enabled architects to get creative with their designs while maintaining peace of mind that they designed for sustainability and creativity.
The design for Gustiny Dvor, Moscow, included flexible spacer and heated glass technology that helped create what is claimed to be Europe’s largest “snow melter” glass roof. The impressive project incorporated flexible foam warm edge for maximum performance in the cold climate of Moscow. This massive roof continues to marvel engineers and visitors alike with its impressive span.
The London Commercial Center, commissioned by the British Land Corporation, is one of the world’s largest exterior lighting projects using color-change LED lights. More than 650 separate glass units are used to display more than 100,000 LED lights, all 5.9 inches wide with five different lengths to give ultimate effects ranging from 1.64 to 6.5 feet. The LEDs are made up of primary colors, but a computer controls color intensity, producing 16 million shades. The square changes color each night.
The project has received many awards since its inception, including the 2004 Winner of Exterior Lighting by the Lighting Industry and Federation, the Light and Design Award by IEIJ and was Highly Commended by FX Awards in 2005. Flexible foam warm edge spacers were recently added to the project to improve upon the previous aluminum spacer bar performance.
The most architecturally interesting aspect of the Woodrow Wilson Bridge Control Tower
is the bridge’s ship-like operator’s tower, an arresting vertical presence in curved glass that emulates the look of an ocean-going ship’s smoke stacks. The multi-panel sections of bent layered glass are in a “dot” frit pattern. Thirteen bullet-resistant curved low-E glass panels and one flat panel total 1,500 square feet of glazed surface. Each of the trapezoid shaped panels measure 6 feet 6 inches wide by 19 feet high. Each of the outboard sections have four glass layers; the inboard ones, two. Each panel weighs more than 800 pounds. The bridge spans the Potomac River, connecting Virginia and Maryland.
What will the future hold?
No one can tell because the possibilities are endless with flexible warm edge technology. With rigid spacer limitations removed, architects have been given the freedom to get creative with insulating glass and create appealing yet functional and energy efficient designs. The science has been provided by innovative companies. The art will be provided by architects who dare to dream big with glass. Stay tuned for more project highlights in future issues.