Larger Than Lite  
Dby eNicmk Sat. nDednis for Big Glass has Fabricators on the Move  
ow big can we go?”  
removed and the glass going to ten feet wide, and  
so on.”  
It’s a question glass fabricators are all too used  
to hearing from the architectural community.  
It’s also one they’re happy to answer.  
sedak North America vice president Maic  
Pannwitz says there has always been a demand  
for large glass, given architects’ love of seamless  
surfaces and unobstructed views. He says sizes  
maxed out around 17 feet in the U.S. and about  
20 feet in Europe until his company recently made  
massive investments in research, development and  
The demand for large, expansive views has  
always played a role in architecture. In recent  
years, it has driven the glass industry to innovate  
and expand its capabilities.  
Coming to the U.S.  
The European market has been a prominent  
user of what would be considered “oversized” glass glass that spans 49 by 101/  
for at least the last decade. German-based fabri-  
cator sedak Inc., for example, was established in  
2007 to cater specifically to that market.  
But as many architectural trends do, the big  
glass movement made its way across the Atlantic  
and has caught on in the United States.  
“Architects and developers have watched the  
technology develop in Europe and other parts of  
the world,” says Garret Henson, vice president of  
sales and marketing at Viracon, which recently  
expanded its glass-size offerings. “Traditionally,  
Now, it can produce laminated and tempered  
2 feet with all of its fab-  
rication treatments. In fact, oversize lites nearly 46  
feet wide currently are being installed at Apple’s  
new Cupertino, Calif., headquarters.  
For sedak, the U.S. market has become a major  
focus over the last two years.  
Glass fabricators  
such as sedak have  
responded in a big  
way to architects’  
growing demand for  
massive lites. The  
company can now  
produce lites in a  
variety of treatments  
spanning 49 feet.  
Home Grown  
Fabricators such as Owatonna, Minn.-based  
Viracon are also addressing the jumbo glass  
The company expanded its size offerings in  
curtainwall spanned five feet wide, and [the design 2006, going from the traditional 84 by 144-inch  
community was] watching the vertical mullions get maximum size to 96 by 165 inches. “We thought  
Architects’ Guide to Glass & Metal  
that was a pretty substantial change in size capa-  
bilities,” says Henson. “But almost immediately,  
architects were asking to go bigger.”  
Viracon responded and is now adding more  
than 360,000 square feet to its headquarters to  
house new glass manufacturing technology and  
fabrication equipment, which will increase its  
maximum finished product size capability to 130  
by 236 inches.  
From about 2010 on, every year the average  
size of the insulating glass unit Viracon has pro-  
duced has grown on a steady curve of about five to  
ten square feet,” he says.  
Optics and Performance  
Pannwitz says a key question architects often  
have is in regard to optical quality.  
When they go with large glass, they want  
low-iron [and not just] clear glass,” says Pannwitz.  
They want as little optical distortion as possible.”  
Large glass also brings with it structural require-  
ments, which involves tempering. He says sedak  
The production of massive glass sizes requires fabricators to make big  
continued on page 22 investments in machinery and technology.  
Catching Fire  
Innovations in the glass industry have a ripple effect. Once a segment of the industry chang-  
es the game, others have to respond. That pattern is not lost on fire-rated glazing, an area of  
the industry where product expansions can be more complicated than others.  
“As the size of the glass increases, it’s crucial that it still maintains the necessary fire rating  
and meets code requirements,” says Jeff Razwick, president of Technical Glass Products. “As a  
result, the glass needs to be tested with a reputable third-party testing agency before it can be  
classified, labeled and sold in the new size.”  
Some types of fire-rated glass are available in larger lite sizes than others, depending on  
whether they are fire-resistive or fire-protective. TGP offers a fire-resistive-rated product avail-  
able in 50-square-foot lites. “This is a far cry from the old 9-square-foot limitations of tradi-  
tional wired glass,” says Razwick.  
Vetrotech also responded to the need for larger sizes by recently expanding its fire-rated  
glass ceramic product and butt-glazed system. Over the past three years, the company conduct-  
ed extensive research and development to conceptualize and produce the larger sizes, modifying  
equipment and optimizing its manufacturing process.  
Meanwhile, Safti First recently tested and approved a fire-resistive glazing product spanning  
more than 55 square feet for oversized and butt-glazed applications. The push from the design  
community, says Tim Nass, vice president of national sales, has been “we want bigger.”  
He says initially, architects wanted a more narrow profile of framing for increased view. But  
the trend then went toward larger lites of glass, which demands a bigger frame, but reduces  
the number of intermediaries.  
They’re willing to accept heavier profiles if they can get more clear views,” he says.  
Since fire-rated glazing on the building’s exterior often only accounts for a portion of its  
entire application of glass, fire-rated companies work to manufacture a product that can mimic  
non-rated glazing seamlessly.  
Our goal is to be as inconspicuous as possible,” says Nass. “We don’t want our products Fire-rated glazing companies are  
to stand out, where someone can look at a building and say, ‘there’s the fire-rated portion.’”  
In addition to new-generation framing solutions, Razwick says designers can now specify  
working to keep up with demand  
for large glass. Safti First recently  
fire-rated systems “with the smooth, frame-free exterior surface of structural silicone glazed cur- tested and approved a 133-by-60-  
tainwall systems,” as well as butt-glazed systems with very narrow joints for interior applications. inch fire-resistive glass lite.  
Summer 2016  
LconatirnugedefrromTphagae 2n1 Lite  
has developed the tempering process “in a way to  
minimize birefringence as much as possible.”  
Henson says it’s important for the industry to  
Glass can accommodate a lot, but it’s still glass  
and if it’s overloaded, it breaks. Designing the cor-  
rect interfaces between the building structure and  
keep a close eye on how larger spans of glass affect the glass is the key.”  
thermal performance and solar control. Another consideration that needs to be made is  
As glass gets bigger, are we introducing our-  
how the sheer increase in size and weight affects all  
parties involved, from the shop to the installation.  
“Think about the logistics of moving these  
larger lites of glass, not only on the jobsite, but  
also for the curtainwall manufacturers within their  
facilities,” says Henson. “That’s important logisti-  
cally and from a safety standpoint.”  
selves back to the window-to-wall ratio battle?” he  
says. “As windows get larger, we have to be sure  
we’re managing these things, as well as visible  
Keep it in Mind  
For every action, there’s a reaction.  
The larger glass gets, the more important fac-  
Thanks to innovations in equipment and the  
will of the glass and glazing industry, the big ideas  
tors such as windload and deflection become—and designers are coming up with in modern-day archi-  
a high premium is put on engineering, particularly tecture can be brought to fruition. And as for the  
from a structural standpoint.  
As a glass supplier, we provide the glass  
growth of glass, will it ever stop getting bigger?  
“I’m sure eventually we’ve got to reach the point  
of no return,” says Henson. “But as we all under-  
stand, given the imagination of architects and devel-  
opers, I don’t think we’re there yet.” AGG  
that the client requests,” says Pannwitz. “…  
Responsibility for the structural concept is  
with the facade contractor. A special glass engi-  
neer should be involved from the beginning when  
building development starts. They have to check  
story drifts, dead loads and building movements.  
Nick St. Denis is the editor of Architects’ Guide to Glass &  
Metal. He can be reached at  
0–23 September 2016  
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Architects’ Guide to Glass & Metal