Glass Canada February 2011 : Page 21better quality polyamide thermal break, which can be as wide as 35 millimetres, de-pending on the design. “The wider the bar, the better it is be-cause it has a greater separation between the exterior aluminum and the interior frame tube. Polyamide is very stable and resilient. It is also protected from UV and stays dry housed in the glazing system. The strength of the thermal break is typically around 80 per cent of the aluminum. A double ‘dog-bone’ configuration design has been around for a long time. One thermal break is under tension and the other is under compression, so they work off each other like a bridge.” There are additional costs associated with upgrading to this type of design. Thermal breaks and their insertion into the aluminum extrusions are not cheap. Without them, however, some glazing systems may not meet the spec. Four-sided structural glazing “There are advantages to the capless 4SSG system in terms of thermal resistance,” says Chan. “With the capless system; one com-monly has rubber or silicone sealant with foam backing, flush with the face of the glass. The entire face of the 4SSG system is the rain-screen and a thermal barrier. The gasket or silicone inline with the face of the glass acts as a thermal break. In order to meet the energy requirements, low-e glass and high-performance spacer bar are still required and gas filled air space may also be a consideration.” When you upgrade to a 4SSG sys-tem, you have to balance out the cost, design and aesthetics. The capped sys-tem is simply using pressure to keep the glass in place and to maintain air/water tightness. 4SSG needs structural sealant and sometimes mechanical method to hold the glass in place. Most 4SSG sys-tems have to be factor y glazed for quality control reasons. New world order “In B.C., our specifications are more stringent than other provinces.” Chan continues, “The B.C. government is taking the lead and other provinces are looking to see what is happening and eventually the rest of the country will probably fol-low. The B.C. Energy Efficiency Act has been implemented for some time. Glazing contractors that design, manufacture and install their proprietary curtain wall and are responsible to meet the specification mostly on a project basis and have some flexibility to get their glazing system to meet the energy requirement.” There is scrambling between some glazing contractors and products distributors on some existing glazing systems. Some parties are pointing fingers, claiming “it’s not my job, it’s your job” to arrive at manufactured products to meet the code. “Some contractors may still tr y to sneak i n a n o n -c o m p l i a n t f r a m e h e re o r t h e re , ” s a y s C h a n . “ H o w e v e r i f t h e y a re c a u g h t , I ’ m s u re t h e re w i l l b e c o n s e q u e n c e s . O n t h e other hand, you have to consider evaluating the thermal performance on a selected glaz-i n g s y s t e m a n d g l a s s b e f o re y o u c a n e v e n b i d on projects.” This will be life in the Canadian glass i n d u s t r y f o r t h e s h o r t t e r m . T h e re w i l l b e confusion and frustration and if we follow our neighbours to the south, likely even l e g a l a c t i o n . L e a n m a rg i n s w i l l b e c o m e l e a n e r. A c h a n g e o v e r o f t h i s s c o p e i s a l w a y s p a i n f u l a n d c o s t l y b u t m o s t a g re e t h a t t h e i n d u s t r y w i l l i m p ro v e a n d e m e rg e s t ro n g e r t h a n e v e r. • Rich Porayko is a professional writer and founding partner of Construction Creative, a marketing and communications company located in Metro Vancouver, B.C. richp@constructioncreative.com Say hello to the future of energy-saving aluminum windows and doors. Introducing mechanical lock profile AZON SAVES ENERGY Contact us to learn about the role of Azon thermal barriers in energy conservation. 1-800-788-5942 | www.azonintl.com GLASS CANADA | JANUARY/FEBRUARY 2011 21 AZON USA Inc. |
