When, Where, Why
For architects, taking the time to understand fire-rated glazing can ensure success
by Ellen Rogers
Fire-rated glass has come a long way since the days of wired glass in hallways and stairwells. From clear glass, to increasingly larger sizes to combining glazing features and benefits, fire-rated glazing not only provides a safe environment, but can also enhance the building’s aesthetics.
Further, building codes and testing requirements are also changing rapidly. As a result architects may be pondering which product to use, when and where. The answers aren’t always clear. However, as design and construction opportunities for fire-rated glass continue to grow, understanding the products as well as when and where to use them can help save re-design—or even re-installation—headaches in the end.
Where to Use it
Fire-rated glass products have evolved tremendously over the past two decades. Architects, designers and specifiers have a wide range of product choices for applications beyond just hallways and stairwells. While product manufacturers say interior applications still remain the primary area for use, new developments allow for increasingly open, transparent designs.
Peter Lindgren, president of Aluflam USA in Huntington Beach, Calif., says much of the work in which they are involved includes institutional projects, schools, hospitals and universities.
“We also do work on commercial buildings, corporate headquarters, hotels and banks. We do very little private residential, though we do get the occasional order where someone wants fire-rated glazing between the home and garage,” says Lindgren, explaining such projects are typically within the very high-end market.
Diana San Diego, marketing director with San Francisco-based Safti First, adds that while fire-rated products are typically installed near exits, exit passageways, stairwells and corridors to provide safe egress for people, they’re also seeing an increasing interest in exterior settings.
“Fire-rated glazing products can be used in exteriors for property line applications, in urban locations or areas prone to wildfire and also places that are adjacent to parking lots,” says San Diego. “We’re getting more and more requests for fire-rated products for use in exteriors.” She explains this is due to the close proximity of property lines, for instance, “especially in areas where they are building pretty much at the property lines.”
Jeff Razwick, president of business development with Technical Glass Products in Kirkland, Wash., agrees that fire-rated glass products are used frequently in interior settings.
“That’s because one of the primary ways to have an overall fire-rating is to compartmentalize and break up the building into small spaces,” he says, adding, though, that they, too, are seeing an increase in exterior applications. “The systems are becoming better equipped for exteriors,” he adds. “Developers are pushing out lot lines and want to use the largest footprint as possible and that can encroach upon proximity.”
Christian Mueller, general manager of Vetrotech Saint-Gobain in Auburn, Wash., adds that the key difference in fire-rated glazing products compared to other fire-rated materials is that these are transparent.
“The intention is to prevent fire from passing along and affecting other parts of the building and that is the main purpose of any passive fire-rated application,” says Mueller.
The question of “where can I use it,” may seem like one that’s answered easily, but that’s not always the case. San Diego says architects and specifiers often ask what type of products they can use for the applications.
“They may have a need for a 1-hour stairwell, so they ask us, ‘what can I us?’” She says one area that causes much of the confusion and misunderstanding is the differences in fire-protective compared to fire-resistive.
“You can have 60-minute fire-resistive and 60-minute fire-protective, but they are not the same,” she says. “Architects need to look at overall performance and what is required for the specific application.” (See box on the right for a look at the differences in fire-resistive versus fire-protective.)
Kevin Frisone, sales and marketing manager, North America, for Vetrotech Saint-Gobain agrees.
“Probably the most discussed [topic] is the two different types, protective and resistive.”
Aside from the protective versus resistive matter, another concern Lindgren points out is understanding the hardware.
“We have to explain that you can’t qualify/maintain the UL listing unless the product is tested as an assembly. It all has to fit within the approved set of requirements,” says Lindgren.
Rated vs. Non-Rated
At first glance a fire-rated product may look much like a non-rated product, but in reality, the two products are very different.
“We now have the ability to go from basic glass to being able to fairly closely match what you can do in non-rated areas,” says Razwick. “We can mimic, match and provide what non-rated systems do in the building and still provide the fire rating.” He continues, “Panels have gotten bigger and frames have gotten narrower. The nice thing from an end-use [perspective] is if you’re walking through a commercial building you can have a hallway filled with glass and not even know it is a fire wall.”
“The fact that these products can pass fire testing is a unique ability,” says San Diego, explaining that the longer the rating the more stringent the testing will be.
The test methods most often used include ASTM E119 for testing doors and windows as well as NFPA 52 or 57, which tests the ability of the products to block smoke and flames.
As with any specialty or value-added product, fire-rated glass also comes at a premium. Lindgren says, though, it can be difficult to give an exact estimate as to how much more, but says it could range from about $100 a square-foot more than a non-rated product.
“I sense that since [Aluflam] came to the U.S. about ten years ago there is now a different level of acceptance and understanding from architects as far as the cost of these products. When we first started here it seemed we got a lot of reaction as far as it being expensive,” says Lindgren. “Today it seems they’ve gotten more used to this type of product and are building it in [to the design] early one.”
He continues, “Certainly there can be budget constraints, but … it’s unfortunate to go through the design and specification process and have it turned down. It’s important to build it in from the beginning.”
Framing requirements for rated versus non-rated are also different.
“The framing has to stay in the opening so there are tremendous loads on that assembly,” says Lindgren. He says he has seen instances where an architect will design the project with a fire-rated system, but provides details on anchoring as one would with a non-rated product. “Everything needs to be in compliance,” he says.
Know the Codes
“All the provisions for fire-rated products are in Chapter 7 of the International Building Code (IBC) and there are three tables that talk about fire-rated door assemblies and windows,” says San Diego. “The references changed with the 2012 code (see box on page 21).” The 2012 code, for example, distinguishes between resistive and protective.
Lindgren points out with the many different testing groups and code bodies, it’s not hard to see where this can be confusing.
“Many of these testing standards are similar, but are from different groups. It’s good to develop an understanding of what’s out there and what’s being listed by the supplier and what will satisfy the needs of the building,” he says.
Fire-rated glazing products have also seen a significant number of changes over the past two decades.
Razwick says architects typically have a design in mind and then want to know how to meet both the code requirements and their design intent. He says architects have become savvy and have recognized these products have changed and lots of options are available.
“They want to know which products will help them [meet those goals],”he says. “The great news is we can address [all of those] design needs. So if they think it and want the clear glass benefits, it is generally possible now [in fire-rated glass]. Rarely is there not a solution to meet the design requirements.”
“Twenty to 25 years ago there was only wired glass. Now you have clear glazing that outperforms wired glass,” says San Diego. “I think that changed the landscape of design and opened a lot of spaces because now you can have stairwells made out of glass—a one- to two-hour stairwell-exterior curtainwall and so much more.”
She continues, “Architects can have more light and incorporate more elegant designs without sacrificing performance or meeting building codes.
According to Frisone, increasingly larger glazing sizes are available and that’s also providing more design opportunities as architects “are constantly looking for ways to bring in more daylight,” he says.
One of the most common materials for fire-rated glazing is steel, with aluminum-clad and aluminum systems also available. The all-aluminum option, such as products manufactured by Aluflam, have only been in the U.S. for about ten years. Lindgren says his company’s product consists of two extrusions separated by a thermal break and filled with a proprietary material, which provides the fire-rated performance features.
While there are a number of options, and framing can be produced to match the aesthetics and colors of the non-rated materials, San Diego, points out the most important detail in framing is that its rating must match that of the glass.
“If the glass is fire-resistive then the framing must be as well. You have to look at the whole assembly,” she says
“The glass and a frame must be tested as a unit/system and not individual components,” he says.
“Architects have to recognize that it’s not a stand-alone product. It works as a system with the overall assembly,” agrees Razwick. “The glass is only one piece that’s providing a fire rating … [it includes] everything down to the sealants, wall systems and gasketing. You have to take a total system perspective. It does no good to have nice fire-rated glass and then put it in the wrong storefront system.”
Get in Early
Experts agree, one of the best measures architects can take when designing with fire-rated materials is to ask questions early and collaborate with their suppliers.
“When working on these projects it’s always best to consult with the manufacturer early,” says San Diego. “Consulting early can save a lot of headaches. The last thing you want to do is pick the wrong product and have to have it changed.”
Lindgren agrees and says he welcomes those calls.
“Sometimes we see specifications [asking for something] that can’t be built. Architects might design the wrong size, use the wrong hardware, etc.”
Mueller adds, though, that while opportunities for architects to use fire-rated glazing materials are growing, education is still needed.
“Some think a sprinkler [which is active] is the cure-all for a potential hazard in a building,” he says. “Both active and passive are important components to building safety. A sprinkler is fire-suppressing not extinguishing.” Mueller says there are those who assume with a sprinkler installed there is then no need for any other protection. “There are lots of passive components that could be neglected.”
“There are those who think if you use active systems there is no need for passive protection and in the 2012 IBC it specifically says you cannot use an active system to provide passive resistance.”
That’s why education and communication is critical and manufacturers agree, early involvement can help create a safe, sound building.
Protective vs. Resistive
Architects commonly ask questions about the differences in fire-protective glass versus fire-resistive. Here’s a close look at the differences and where each product type can be used.
Fire-protective glass is designed to compartmentalize smoke and flames and is subject to application, area and size limitations under the IBC. Fire-protective glass is typically used in doors and openings up to 45 minutes and cannot exceed 25 percent of the total wall area because it does not block radiant heat transmission.
Fire-resistive glass is not limited in application or size. This type of fire-rated glass compartmentalizes smoke and flames, and blocks the transmission of dangerous levels of radiant heat through the glazing. As a result, it can be used in wall and door applications 60 minutes and above without the size limitations that apply to fire protective glass.
Source: Safti First
What do the codes say about fire-rated glass and what’s most important for architects? Thom Zaremba, code consultant for the Glazing Industry Code Council, provided the following information on the three tables noted in Chapter 7 of the IBC.
Table 716.3. This tells everyone exactly what the [glass] marking system is; the specific fire test standard to which each mark relates; and, lastly, in the definitions it provides, it ties the acceptance criteria of each test standard (or the code in the case of the “temperature rise” criteria) to the marks that are used in the new system. Markings include “W,” which means that the glazing has been tested to the fire wall test standard (ASTM E-119/NFPA 251/UL 263) and thus classified as fire resistive; “D” means the product has been tested to the fire door test standard, NFPA 252; “H” means that it passes the hose stream procedure; “T” means that the glazing meets the temperature rise limits required for doors used in exit enclosures and passageways; and “OH” means that the glazing has been tested to the fire window test standard, NFPA 257, and meets both the fire endurance and hose stream requirements of the test standard.
Table 716.5. This table addresses fire doors and fire shutters, vision panels in fire doors and the transoms and sidelites that are often found in combination with fire doors. This table provides a listing of every different type of opening fire-protective assembly specified by the code and relates each one to its required wall rating, its corresponding minimum fire door and fire shutter assembly rating as well as the building code ratings and requirements relating to the vision panels, sidelites and transoms found in them. It then goes on to provide comprehensive listings of all the markings that must be found on the different types of fire rated glazings that may be used in those assemblies.
Table 716.6. This table addresses fire window assemblies. Like Table 716.5, it provides a listing of the fire-rated wall assemblies where fire-rated windows may be found, the corresponding wall assembly ratings, the associated minimum fire window assembly ratings, and the markings that must be found on the fire-rated glazings used in those assemblies.
Zaremba adds, “The current system is quite developed and should simplify an architect’s ability to select the right fire-rated glazing product for the right application.”
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