David Vermeulen, the Midwest territory manager for Technical Glass Products, spends a lot of time talking with Building Teams about impact glazing and fire-rated glass. “There’s still a little confusion about the products—on the types of glass available, how they’ve changed over the years, and how they can be used,” he says. “People are surprised by what they can do with fire-rated glass.”
Here Vermeulen shares some back-to-basics answers to seven common questions about impact glazing and fire-rated glass.
1. How does fire-rated glass differ from ordinary glass?
Fire-rated glass has been tested to act as a barrier to the spread of flames and smoke, a practice known as compartmentalization. The framing and glass undergo independent testing from such organizations as Underwriters Laboratories, where a fire is ignited and the temperature (which can be as high as 1,000ºF after only five minutes) is measured on the surface of the glass. Ratings are given based on the length of time the glass remains intact. The test concludes by blasting the heated glass with water from a two-man fire hose to determine the system’s ability to withstand impact pressure and its resistance to thermal water shock. Fire-rated glass ratings range from 20 minutes up to three hours, depending on the product and framing system.
2. When using glass in fire-rated locations, is impact safety glass also required?
No. Building codes determine where impact safety glass is required. “Generally speaking, any glass 18 inches off the floor or 36 inches from a door—and any door glass itself—has to be safety glass,” says Vermeulen. However, a transom over a door would not require the use of impact-rated glass, so a fire-rated glass that is not impact rated could be used and is a less expensive option than glazing offering both impact- and fire resistance.
3. What types of impact glazing are available?
There are two types: Category I and Category II.
Category I represents 150 foot-pounds of impact, which simulates a small child (approximately 85 lb) running into the glass. Glass meeting this test is limited to a maximum size of nine sf per lite.
Category II represents 400 foot-pounds, which simulates an adult running into the glass, and is the highest level of required impact-rated glass. With few exceptions, all tempered or laminated glass in use falls into this category, and any opening over nine sf has to meet category II standards.
4. What types of fire-rated glass are available?
Two types: thin and thick.
Thin glass is approximately 1/4- to 5/16- inch thick and fits into standard fire-rated steel frames. Thin glass is now available in larger sizes than previously offered—allowing greater design flexibility and larger openings for increased daylighting transfer—with fire ratings from 20 to 90 minutes. Thin products are classified as “opening protective” and block smoke and flames, but are not heat barriers. Thin products are available with or without impact ratings.
Thick glass products, commonly called glass walls because they allow virtually unlimited expanses of glass and are typically used in areas where glazing exceeds 25% of the wall area, measure ¾ inch or more in thickness and are tested to the same standards as solid barrier walls. Fire ratings for thick glass range from 45 minutes up to two hours, and the products block smoke and flames as well as heat.
5. Does fire-rated glass limit design possibilities?
No. “Design possibilities have reached new heights, and that’s triggering a change in the way projects are being built,” says Vermeulen. Advances in glass technology and framing materials address limitations on window sizes and allow windows to meet the same code requirements as a firewall. Vermeulen says designers are now able to use fire-rated glass instead of traditional wall construction to bring more natural daylight into the interior. “We even have fire-rated glass floors now,” he says. New labeling that makes it easier for code officials to determine whether or not the proper glass is used in the space will be part of the International Building Code for 2012.
6. Are fire-rated products more expensive?
Fire-rated glass is more expensive than traditional glass, and typically accounts for 2% of a building’s total budget, according to Vermeulen.
7. Is fire-rated glass traditionally an interior product?
Yes, but that’s changing somewhat. “Insulating fire-rated glass for exterior use is a new thing,” says Vermeulen. In general, fire-rated glass is used on a building’s exterior in cases where adjacent buildings are very close to the property line, to keep fire from leaping from one building to the next. BD+C
David Vermeulen has nearly a decade of fire-rated glazing experience, and has successfully worked with code officials, architects, and designers from schematic product development through installation.
Related Stories
| Nov 11, 2010
USGBC certifies more than 1 billion square feet of commercial space
This month, the total footprint of commercial projects certified under the U.S. Green Building Council’s LEED Green Building Rating System surpassed one billion square feet. Another six billion square feet of projects are registered and currently working toward LEED certification around the world. Since 2000, more than 36,000 commercial projects and 38,000 single-family homes have participated in LEED.
| Nov 10, 2010
$700 million plan to restore the National Mall
The National Mall—known as America’s front yard—is being targeted for a massive rehab and restoration that could cost as much as $700 million (it’s estimated that the Mall has $400 million in deferred maintenance alone). A few of the proposed projects: refurbishing the Grant Memorial, replacing the Capitol Reflecting Pool with a smaller pool or fountain, reconstructing the Constitution Gardens lake and constructing a multipurpose visitor center, and replacing the Sylvan Theater near the Washington Monument with a new multipurpose facility.
| Nov 9, 2010
Just how green is that college campus?
The College Sustainability Report Card 2011 evaluated colleges and universities in the U.S. and Canada with the 300 largest endowments—plus 22 others that asked to be included in the GreenReportCard.org study—on nine categories, including climate change, energy use, green building, and investment priorities. More than half (56%) earned a B or better, but 6% got a D. Can you guess which is the greenest of these: UC San Diego, Dickinson College, University of Calgary, and Dartmouth? Hint: The Red Devil has turned green.
| Nov 9, 2010
12 incredible objects being made with 3D printers today
BD+C has reported on how 3D printers are attracting the attention of AEC firms. Now you can see how other creative types are utilizing this fascinating printing technology. Among the printed items: King Tut’s remains, designer shoes, and the world’s smallest Rubik’s Cube.
| Nov 9, 2010
U.S. Army steps up requirements for greening building
Cool roofs, solar water heating, and advanced metering are among energy-efficiency elements that will have to be used in new permanent Army buildings in the U.S. and abroad starting in FY 2013. Designs for new construction and major renovations will incorporate sustainable design and development principles contained in ASHRAE 189.1.
| Nov 9, 2010
Designing a library? Don’t focus on books
How do you design a library when print books are no longer its core business? Turn them into massive study halls. That’s what designers did at the University of Amsterdam, where they transformed the existing 27,000-sf library into a study center—without any visible books. About 2,000 students visit the facility daily and encounter workspaces instead of stacks.
| Nov 9, 2010
Turner Construction report: Green buildings still on the agenda
Green buildings continue to be on the agenda for real estate owners, developers, and corporate owner-occupants, according to the Turner 2010 Green Building Market Barometer. Key findings: Almost 90% of respondents said it was extremely or very likely they would incorporate energy-efficiency improvements in their new construction or renovation project, and 60% expected to incorporate improvements to water efficiency, indoor environmental quality, and green materials.
| Nov 5, 2010
New Millennium’s Gary Heasley on BIM, LEED, and the nonresidential market
Gary Heasley, president of New Millennium Building Systems, Fort Wayne, Ind., and EVP of its parent company, Steel Dynamics, Inc., tells BD+C’s Robert Cassidy about the Steel Joist Manufacturer’s westward expansion, its push to create BIM tools for its products, LEED, and the outlook for the nonresidential construction market.
| Nov 3, 2010
First of three green labs opens at Iowa State University
Designed by ZGF Architects, in association with OPN Architects, the Biorenewable Research Laboratory on the Ames campus of Iowa State University is the first of three projects completed as part of the school’s Biorenewables Complex. The 71,800-sf LEED Gold project is one of three wings that will make up the 210,000-sf complex.
| Nov 3, 2010
Park’s green education center a lesson in sustainability
The new Cantigny Outdoor Education Center, located within the 500-acre Cantigny Park in Wheaton, Ill., earned LEED Silver. Designed by DLA Architects, the 3,100-sf multipurpose center will serve patrons of the park’s golf courses, museums, and display garden, one of the largest such gardens in the Midwest.
