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This morning's joint session on insulating, laminated and tempered glass during the Glass Fabrication and Glazing Educational Conference covered a wide range of topics aimed at fabricators. Henry Taylor of Kawneer opened the session with a presentation on "How the Glass Industry Can Contribute to LEED and Green Building." Focusing on sustainability was his first suggestion. "We have the technology to make these buildings last-let's go ahead and do that." According to Taylor, the goal had been to produce buildings that last 25 to 30 years, but new technology is driving manufacturers to create products that last as long as possible to limit the impact on the environment. Now it's not unusual to aim for a building that will last without problems for 60 or 70 years. Hand-in-hand with sustainability and making materials last is the renewed focus on using recycled content. He explained that programs such as the U.S. Green Building Council's LEED system are looking for materials that use pre-consumer recycled material (which has not yet gone out into the field and been used) as well as post-industrial recycled content.
Recycling is a concept that's been around for a while but has renewed importance today. But among the "trendiest" ways in which glass is contributing green today is through photovoltaics (PV) or solar cells. "We're seeing a lot of opportunities in spandrel areas … to use PV," Taylor said. Slope glazing is another application where these products are gaining in popularity, and replacing such products as sunshades and patterned glass that help create shading. According to Taylor, PV is popular in these applications since these opaque products not only cut down on heat but also create energy. A member of the audience asked if Taylor thought the limited size availability of PV panels is a reason the technology is not more often specified by architects. Taylor noted that most architects are aware that there aren't many size options yet since it's a new (and growing) technology and don't mind working with what's available. He did note, however, that it may take more motivation than simple green consciousness to further promote the use of these environmentally friendly products. "To get this moving at a much faster pace the government is going to have to step in to get the momentum going," Taylor said. Some small such efforts are already being used. "When it comes to photovoltaic, the government will give a 50 percent tax credit to an owner for [using] photovoltaic in a building," he said.
As far as sustainability and making those products last longer, Chris Barry of Pilkington took the podium to discuss"Why Glass Sometimes Breaks." Essentially, he explained, glass breaks when an applied load exceeds the strength of the glass. The real question is: when a break occurs, was the load too great or was the glass too weak? To begin to answer that question, Barry noted, means asking how strong glass is, and that's where the problems begin."We don't really know," he said. "We know how strong it mightbe." For example, in taking 1,000 samples lites and applying force, by the time 9,000 psi was reached, eight lites still hadn't broken. In other words, each lite reached its breaking point at different time. There are a couple of common causes of breakage, however: tensile stress (including bending, thermal stress and NiS inclusion and expansion); impact; and crushing. To determine what might be the cause, fractographics can be used to examine the break-if there's enough time and money and all the broken pieces are still available, Barry added.
From the strength of glass, attendees turned their attention to the strength of codes and standards about glass. Mark Gold of Solutia presented an introductory session on some of the important industry-related building codes and standards. But first, he explained the difference between these two regulations: codes are mandatory and standards are voluntary until they are referred to by a code. Among the code-making bodies with relevant glass standards are:
In addition, three groups primarily oversee standard preparation:
Industry organizations work with these code and standard making bodies to constantly update and create new regulations in response to marketplace demand and new trends; trends such as those discussed by Don McCann of Viracon during his presentation "Changing Trends in Glass Uses." Among the demands he's hearing from architects is that of more glass. "We're starting to see more floor to ceiling glass," McCann said. And on that glass, architects are demanding high-performance coatings. He noted that more hybrid materials being used to get the best of all performance features, from high visible light transmittance (VLT) to low U-values and more. High VLT in particular has become much in demand. And, McCann said, "That's one of the hardest things to get an architect off of." Not to persuade architects away from letting in more light-but educating them about what high VLT really means in a building and how a combination of coatings can create a room that has lots of visibility and is still comfortable to occupants. In addition, McCann said that he has seen more architects push for low U-values, which he expects will be obtained through more demand for gas filling in insulating glass units. "Gas filling is going to start becoming more important," he said. Laminated glass also is still growing, McCann said, for hurricane-resistant and security applications, as well as acoustic. What's driving these trends? Among several factors is the biggest trend of all, the focus on energy. As McCann noted, the costs of energy continue to rise. "When you start looking at building applications-buildings tend to be one of the higher consumers of electricity as well as natural gas." Need more info and analysis about the issues? |
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