Volume 50, Issue 9 - September 2015

The Big 4
Overcoming the Challenges of
Producing Oversized IGUs

by Megan Headley


It was only a matter of time before two of the biggest trends in glass—demand for better performance and interest in ever-larger sizes—converged into a new trend. Now, as fabricators hear more inquiries about larger-than-ever insulating glass units (IGUs), they are facing challenges to meet this trending development. Here’s a look at what some companies point to as the biggest ones they’re facing.

Challenge 1: Sourcing Bigger Glass

In the United States, oversized glass is becoming a more common expectation among architects and, consequently, the glass industry. But expanded handling and production capabilities overseas are pushing U.S. fabricators to think big for higher-performing units.

“For us here at Bystronic, we really do not consider anything outside 200 by 106 inches as oversized, per se. The reason for this is the trend with some of our customers in Europe has been pushing the limits for some time now,” says Scott Knisely, president of Bystronic North America in Aurora, Colo. “Here in North America though, it [has been] rare to see requests for sizes exceeding this boundary until more recently. We would now consider requests for sizes between 96 by 130 inches to 130 by 204 inches as oversized for this market” (see “Defining ‘Big’ IGUs” on page 74 for more on sizing).

Joe Erb, commercial sales specialist for Houston-based Quanex, agrees that part of the push to go bigger comes from the pressure to keep up with overseas suppliers.

“The maximum [IGU] size in the U.S. has been around 156 inches in the past,” Erb says. “With offshore companies offering sizes well in excess of this, U.S. fabricators invested in cutting, tempering and insulating lines to produce IGUs up to 98 inches high or 198 inches long.”

However, providing those sizes with high-performing coatings has been a challenge as the primary glass suppliers are still in the early stages of offering them.

“One of the greatest challenges of these humongous units is the availability of glass in stock sheets that will allow us to cut these oversized products. It is only within the past two years that Vitrum has acquired access to low-E glass products in excess of 144 inches,” says Michael Zizek, marketing director for Vitrum Glass Group in Langley, British Columbia. “Clear glass and some tints are available in oversize lites. However, this is often not the case for low-E coated glass as the MSVP coaters in North American are unable to process these oversized sheets.”

Erb agrees. “This has been a significant challenge in recent years,” he says. “Guardian has offered their coatings in oversized sheets for a while, and PPG is soon going to have their coatings in larger sizes as well.”

But for some, available oversized products still aren’t big enough.

Zizek has found that flat glass suppliers are still slow to offer “oversized” options with low-E capabilities.

“In late 2013, Guardian began offering SN68 in an ‘oversized’ option with a maximum sheet size of 102 by 168 inches to complement its existing 96- by 130-inch and 102- by 144-inch stock sheet sizes,” he says. “Vitrum, however, offers a maximum IG size of 98 by 190 inches. We still didn’t have access to a low-E glass product that met or exceeded our fabrication capabilities.”

The company now serves as a certified fabricator of Saint-Gobain products. That allows it to stock SKN 174 in a sheet size of 126 by 200 inches, which allows the company to produce oversized units with low-E coatings.

“One of the greatest challenges of these humongous units is the availability of glass in stock sheets that will allow us to cut these oversized products. It is only within the past two years that Vitrum has acquired access to low-E glass products in excess of 144 inches,” says Michael Zizek, marketing director for Vitrum Glass Group in Langley, British Columbia. “Clear glass and some tints are available in oversize lites. However, this is often not the case for low-E coated glass as the MSVP coaters in North American are unable to process these oversized sheets.”

Erb agrees. “This has been a significant challenge in recent years,” he says. “Guardian has offered their coatings in oversized sheets for a while, and PPG is soon going to have their coatings in larger sizes as well.”

But for some, available oversized products still aren’t big enough.

Zizek has found that flat glass suppliers are still slow to offer “oversized” options with low-E capabilities.

“In late 2013, Guardian began offering SN68 in an ‘oversized’ option with a maximum sheet size of 102 by 168 inches to complement its existing 96- by 130-inch and 102- by 144-inch stock sheet sizes,” he says. “Vitrum, however, offers a maximum IG size of 98 by 190 inches. We still didn’t have access to a low-E glass product that met or exceeded our fabrication capabilities.”

The company now serves as a certified fabricator of Saint-Gobain products. That allows it to stock SKN 174 in a sheet size of 126 by 200 inches, which allows the company to produce oversized units with low-E coatings.


At Vitrum Industries, operators handle glass lites as large as 98 by 190 inches. Once these lites are transferred onto a vertical sealing line they will be fabricated into IGUs that weigh almost 800 pounds after they’re sealed.


Challenge 2: Setting Up Shop

Getting the right material is but the first, and perhaps simplest, hurdle for fabricators to overcome when they look to fill the niche demand for oversized IGUs. As Erb notes, making the capital investment to find available floor space for larger equipment to produce this oversized/jumbo commercial IG (tempering, insulating) is the first major challenge to overcome.

A significant part of that investment will come from an oversized IG production line, but further expenditures are needed for appropriate handling equipment.

“These larger sizes mean thicker glass is required to handle stresses and design loads. This compounds weight and handling issues,” Erb says.

“Naturally, the challenges are with handling the larger glass,” says Morgan Donohue, vice president of Erdman Automation Corp. in Princeton, Minn. “Equipment for large glass, such as manipulators or cranes, needs to be in place and these are not always convenient to use on smaller glass.”

According to Vince Warne, director of technical services for Quanex, automated applications and vacuum or mechanical assisted-lifting devices are being developed to help overcome these handling challenges.

Handling equipment is a crucial part of the equation. Remember, though, every piece of equipment, not just your insulating lines, must be able to handle the larger glass.

“Having an oversized IG line has no value if the cutting station, tempering oven and washers can’t also accommodate the maximum size,” Zizek points out. “This includes receiving, cutting, washing, tempering, laminating and, finally, the fabrication of the IGU. If any of these areas is unable to handle oversize glass, it becomes challenging or impossible to produce oversized IGUs.”

Knisely advises fabricators to really consider their space and the logistics required to safely fabricate glass of this size. “We spend a lot of time with clients, not only discussing the capabilities of the equipment, but how to move glass on and off equipment safely,” he says.
Machinery manufacturers have responded to the trend toward over-sized IGUs with equipment capable of meeting these demands.

Challenge 3: Meeting Performance Expectations

There’s one investment beyond materials and equipment that’s needed before a fabricator rushes into production of these oversized products: staff training and know-how. As the glass gets bigger, achieving today’s expected performance levels is different than it is for standard-sized IGUs.

For example, large units are prone to center-of-glass deflection, Zizek says. He advises that “A larger airspace may be required and careful handling necessary to ensure the glass and/or coating within the sealed air cavity is not damaged due to the contact caused by the inherent bow of oversized glass. An automated vertical sealing line helps overcome some of these challenges.”

Bob Cummings, southwest regional sales manager with the Dallas branch of Hartung Glass Industries, agrees.

Machinery such as Erdman’s 7000 series spacer applicator can be used for large-sized glass fabrication; this unit was large enough that it required two people to carry it.

“Heat-treated, oversize IGUs create a high level of difficulty in terms of keeping glass flat relative to bow and warp, as well as roll wave distortion. Architects and building owners are expecting these larger oversize units to mimic the quality levels of a 20-square-foot unit,” he says.

Fabricators can also expect differences with the spacers.

“Oversize IGs require spacer bars that are extremely large and difficult to handle and place due to their large size and flexibility,” Zizek says.

Knisely encourages clients to look beyond rigid spacer systems into flexible options. “The challenges with very large units, in both width and height, tend to make traditional box spacer manufacturing even more challenging in terms of spacer application,” he says. “Our experiences in Europe and Asia clearly show utilizing a flexible spacer system … can have an immediate payback in terms of space optimization, production planning, labor and high-quality yields.

Ensuring everything is produced as expected brings additional challenges.

“It is [traditionally] more difficult to inspect the [oversized] glass. Larger glass fabrication is simplified with larger inspection equipment,” Donohue says.

“We work with industry partners to integrate automatic inspection systems inline to reduce the potential defects that could be missed in the final product due to poor glass quality,” Knisely adds.

And of course, with bigger glass comes longer production times.

“The fabrication process of large IG units can slow down production and throughput,” Cummings says.

Defining “Big” IGUs

What exactly is considered oversize when it comes to today’s insulating glass units (IGUs)? And where is this demand taking place? Answers to those questions vary widely, with the only agreement being that these high-performing units are getting larger.

Vince Warne, director of technical services for Quanex in Houston, is seeing demand for increasingly larger IGUs along the West Coast and other coastal markets. This demand includes wall and door systems, picture walls and light commercial products measuring greater than 30 square feet. “[We’re] seeing more displays of large folding door units, as well as what would be considered typically light commercial used in residential for large open views,” he says.

Michael Zizek, executive assistant for Vitrum Glass Group in Langley, British Columbia, says “We are seeing a growing demand in the past two years for IGUs that push past what we typically consider oversize (between 50 and 70 square feet) and into the humongous, with units pushing 130 square feet,” he says.

Given the expectation for larger monolithic lites, and the new capabilities of companies, it can safely be assumed that bigger IGUs will be a part of the future.

“The architectural market has been trending bigger and better in terms of glass sizes based on aesthetics and focusing on increasing the amount of natural light into a building. The newer advanced coatings allow this without a penalty to the building’s energy efficiency based on very low SHGC and U-values,” says Bob Cummings, southwest regional sales manager with the Dallas branch of Hartung Glass Industries. “In the past, many fabricators would limit their IG warranty to 50 square feet with exceptions taken in terms of ASTM standards for anything greater. The industry is seeing sizes in the 60- to 70-square-foot range on a consistent basis.”


Once produced, there’s another factor to consider: getting it onsite.

“The overhead cranes, receiving bays and trucking to accept these oversize shipments all create challenges,” Zizek points out. “Not all trucking companies and fabricators can transport and receive oversize stock sheets. Not all glaziers can accept shipments of oversize units due to their weight and size.”

Yet Erb sees a potential issue even beyond delivery of the final product.

“I see the bigger challenge moving forward as one of dealing with these oversized IGUs in the field if/when something goes wrong (i.e. glass breakage or failure). The logistics and cost associated with such replacement will be significant, especially in the larger cities like New York,” he says.

Fabricators must also educate their customers on the challenges they might expect to face.

“Glaziers and architects need to be educated on the challenges and costs of handling and installing oversized glass units. Glazing systems must be capable of supporting the weight and the appropriate machinery and material handling is required to get it installed at the jobsite,” Zizek says.



Tomorrow’s Trend

As these trends emerge, more architects likely will expect to incorporate these high-performing products into bigger spaces. The biggest flaw in today’s trend toward oversized glass, though, is meeting increasingly stringent energy requirements.

“Architects, designers and building owners want to allow more visible light in and eliminate the obstruction of a metal frame. With the increased glass size comes challenges with energy performance, especially if monolithic or non-low-E glass is used in an IGU,” Zizek says.

These challenges will all become increasingly easier to overcome as today’s oversized glass becomes tomorrow’s standard size.

“The successful players have invested capital in world-class equipment capable of handling the larger sizes while profitably meeting or exceeding the customer’s expectations,” Cummings says.


the author
Megan Headley is special projects editor for USGlass magazine. She can be reached at mheadley@glass.com.


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