The Future of Fire-Rated Glass and Framing
Frame Cover Caps and Finishes
In addition to specifying narrow fire-rated frames, designers can select from a wide array of versatile frame cover caps and finishes to help match fire-rated frames to nonrated frames used in other parts of the building. This means that architects can now more closely mirror the aesthetic of nonrated systems, providing greater design freedom. In terms of the appearance of fire-rated frames, there are ever-expanding opportunities for building teams to achieve virtually any look to complement non-fire-rated frames. This “match” can be accomplished in a number of ways, including:
Custom paints or powder coats: Frames can be custom painted, anodized, or powder coated to match nearly any color scheme. This includes the more traditional material matches like the silver color of aluminum to bold colors like purples and reds.
Materials and cover caps: Designers now have fire-rated frame options ranging from authentic hardwood to products with the look of stainless steel. For example, one popular finish option is durable stainless steel. It matches the bright, contemporary aesthetic of stainless steel used in other building finishes. Fire-rated frames are also available with custom aluminum cover caps for a cohesive look.
Shapes and sizes: The face caps are available in numerous shapes and sizes, from H and I shapes to custom configurations.
Alternatively, while achieving a seamless, complementary visual match between fire-rated and non-fire-rated elements is an important design goal, other building projects demand a way to differentiate designs through framing. This can be achieved through various options, including the installation of fire-rated glass and frames featuring custom corners and angles, which is one way to create a visual point of interest while working within the parameters of code-driven applications. Additionally, custom finishes (e.g., wet painting or powder coating carbon steel frames in a variety of colors) can be used to create a one-of-a-kind aesthetic and make a visual statement.
CASE STUDY: JOHNSON & WALES UNIVERSITY CENTER, PROVIDENCE, RHODE ISLAND
Challenge: A key component of DBVW Architects’ plans to turn a historic jewelry factory into a high-tech facility for Johnson & Wales University physician assistant students was creating an open, vibrant atmosphere. The original building had tall ribbon windows, which transferred light across its wide floor plate. However, since the window sills were 5 feet above the floor, they restricted visibility. Building occupants were unable to see the city streets, and pedestrians could not see inside. In addition, the existing structure’s opaque form held little visual stopping power at the street level.
The building’s lack of openness and accessibility to the street was a concern for the design team. “The original main entrance to the building was not handicap accessible and not as grand as we envisioned for Johnson & Wales’ new Physician Assistant Program,” explains Sean Redfern, associate principle for DBVW Architects. “You entered into the building through a nondescript concrete block staircase. There was no sense of arrival or the importance of the building.”
Solution: To achieve the desired transparency, the firm opened up the building’s exterior walls along the southeast street and developed a new, porous entry with floor-to-ceiling glass. The first floor of the entry features a lounge and lobby, with a prominent stairway leading up to the second floor. For the lobby and stairs to successfully work together to create a clear circulation path for people coming into the building, the firm faced the challenge of finding a fire-rated glazing system that satisfied building codes while also supporting transparency to the entry. DBVW Architects found the solution by combining new narrow-profile fire-rated frames with a transparent fire-rated glazing.
“The entry is the only area in the building where people can look into the building from the outside and sense what’s happening inside,” Redfern says. “Together, the thin-profile fire-rated frame design and clear fire-rated glass helped us achieve the transparency and fire protection we were looking for in the space.”
The precision engineering and crisp sightlines achieved provided an attractive, modern alternative to traditional hollow metal frames for fire-rated applications. The flexibility to use custom aluminum face caps allowed the design team to further match the building’s clean, open aesthetic. DBVW Architects selected custom, H-shaped aluminum cover caps, creating a framing system with sleek, linear profiles. This particular aluminum frame series can be used in applications requiring a 2-hour barrier to radiant and conductive heat transfer.
The fire-rated and impact safety-rated glazing material used is fire-tested as a wall assembly, allowing unrestricted amounts of transparent glazing. The product offers fire ratings of up to 2 hours and blocks the transfer of radiant heat, providing essential protection should students need to exit the building during a fire. It also meets the impact requirements of CPSC 16CFR1201 Category I and/or Category II—a critical performance benefit for glass used in busy stairwells.
“Using fire-rated glass for an entire exit stair enclosure isn’t something you see every day,” Redfern adds. “But the openness that the system created fit well with our design aspirations.”
Photo courtesy of Heidi Gumula | DBVW Architects
Custom cover caps and slender fire-rated frame profiles create an attractive, modern alternative to traditional hollow metal frames.
Silicone-Glazed (SG) Fire-Rated Curtain Wall Systems
Over the past decade, manufacturing advances have given rise to fire-rated curtain walls with narrow mullion profiles and large expanses of fire-rated glass. Yet, despite these developments, it remained challenging for designers to match the seamless aesthetic of structural SG curtain wall systems.
To achieve the functionality of a clean, uninterrupted exterior surface, manufacturers began producing fire-rated curtain walls that emulate the smooth, monolithic appearance of SG curtain walls. One available assembly is silicone sealed and requires no pressure plates or caps. Its patented toggle retention system anchors the glazed lites and becomes completely hidden once installed, creating an attractive frame-free look. The system is available with up to 120-minute fire ratings and can accommodate full-lite doors for a complete curtain wall entrance solution. Such silicone-glazed fire-rated curtain walls can satisfy life safety requirements without sacrificing transparency. In application, these sleek, high-performing fire-rated glass systems are ideal for architects with stringent design and life safety criteria in highly visible areas, including prominent entryways, lobbies, and corridors.
CASE STUDY: 929 OFFICE TOWER, BELLEVUE, WASHINGTON
Challenge: To attract big-name tech tenants, LMN Architects desired a stylish glass-clad exterior with the frame-free look of silicone glazing. However, building codes required that portions of the upscale building’s ground floor exterior be fire rated to prevent a fire from traveling to or from neighboring buildings on one of Bellevue’s 600-foot-by-600-foot downtown “superblocks.”
Solution: To bring fire and life safety in line with the building’s design intent, the firm used the monolithic aesthetic of a silicone-glazed fire-rated curtain wall system. It helped ensure smooth visual transitions at junctions between the rated and nonrated systems while providing critical protection against the spread of fire between adjacent structures.
Photo courtesy of Technical Glass Products (TGP)
Clean sightlines and a seamless aesthetic bring fire and life safety in line with the building’s design intent.
Butt-Glazed Systems
Over the past decade, manufacturing advances have created fire-rated glass wall panels with butt-glazed joints in a heat-resistive, fire-rated perimeter frame, providing yet another rung in the ladder of fire-rated glazing with aesthetics comparable to those of nonrated systems. These systems are unique in their ability to allow designers to more closely match the continuous glass wall aesthetic, which is widely seen in interior nonrated glazing applications. In fact, the sleek, monolithic look of these systems makes it almost impossible for the average occupant to visually discern that there are space subdivisions providing unparalleled fire safety.
One of the key ways that some manufacturers are able to reduce the width of vertical butt joints and create this sophisticated aesthetic is to use fire-resistive glass with a solid multilaminate glass makeup. This eliminates the need for internal spacers and edge sealants, resulting in butt joints as narrow as 5 millimeters (butt joints on current fire-rated systems are typically 41 millimeters or greater). It also allows the system to have virtually unobstructed transitions between adjoining pieces of fire-resistive glass. The result is longer spans of uninterrupted glass free of vertical mullions, and with improved views and enhanced light transmission.
To further enhance design flexibility, some manufacturers offer systems in which the perimeter of each butt-glazed elevation can be maintained by the fire-rated framing choice most conducive to meeting the designer’s specific project goals. This includes predetermined fire-resistive framing options from the manufacturer, as well as L-angle steel frames by others.
Overall, today’s butt-glazed fire-rated glass wall systems are a great choice for interior applications in fire-rated corridors, fire-rated stairwells, and other interior areas of egress where it is key not only to match the aesthetic of nearby nonrated systems but also to provide effective compartment divisions.
CASE STUDY: THE UNIVERSITY OF KANSAS EARTH, ENERGY & ENVIRONMENT CENTER, LAWRENCE, KANSAS
Challenge: The Earth, Energy & Environment Center (EEEC) at the University of Kansas is one of the latest state-of-the-art educational buildings located at the University of Kansas. The facility houses classrooms and laboratories for faculty, staff, and students to conduct research on energy production and the environment. According to a Cannon Design project write-up, “The building is a figurative and literal bridge between basic and applied sciences.” It is designed to “transform traditional academic barriers and create a dynamic environment for research teams and students.”
To create the innovative facility, a key goal during the design phase of the EEEC was to create transparent learning areas that would allow fellow students and peers to look into active labs and tech areas, promoting inspiration and discovery. One challenge was maintaining the open, shared-use research concept in areas requiring fire resistance by code. This included the main entrance and second-floor corridor overlooking the stairway.
Solution: The solution was to use a 60-minute fire-rated system that incorporates butt-glazed fire-resistive glass with a fire-resistive perimeter frame. Since the system does not require glass units with internal spacers and edge sealants, it allows for nearly colorless transitions between adjoining pieces of low-iron glass while still serving as a barrier to radiant heat. The resulting system complements the non-rated butt-glazed systems used throughout the building. When combined with the narrow profiles of the perimeter frame, it provides unhindered views into and out of windowed laboratories and enhances light transfer.
Photo courtesy of Technical Glass Products (TGP)
With nearly colorless transitions between pieces of fire-rated glass, butt-glazed fire-rated glass systems improve sightlines and views in code-driven spaces.
Fire-Rated Glass Floors
Gone are the days when architects and specifiers found themselves limited to concrete, gypsum, and masonry for code-approved fire barriers between floors. While these opaque materials technically get the job done, aesthetically, it’s a different story. By their very nature, these traditional materials limit views and light transfer through building levels. With recent manufacturing advances in fire-rated glass floors, however, design professionals now have an alternative.
Fire-rated glass floor systems can provide fire resistance while transmitting light deep into a building’s core. The innovative systems can provide a dramatic way to expand glazing in a host of building types. They can facilitate views and increase admissible daylight while supporting structural loads and blocking flames, smoke, and heat.
Design professionals can now specify fire-rated glass in a range of horizontal applications, including:
- non-egress floor applications requiring 60- to 90-minute fire ratings;
- egress floor applications requiring 2-hour fire ratings;
- glass punch-outs in fire-rated corridors; and
- atriums.
Current advanced fire-rated glass floor systems on the market typically have three main components:
- top-surface glass;
- a structural framing grid; and
- fire-resistive glass
CASE STUDY: NORTHWESTERN UNIVERSITY ENGINEERING LIFE SCIENCES, EVANSTON, ILLINOIS
Challenge: Northwestern University’s Engineering Life Sciences infill is a bright, multidisciplinary space with collaborative gathering areas and cutting-edge classrooms, laboratories, and research rooms. The expansion rises five stories, bridging two of the campus’ existing building wings. It is designed to LEED Silver standards.
“The original building had courtyards that were turned into parking lots,” explains Matt Garrett, project architect at Flad Architects. “The infill makes use of this previously underused space and encourages interconnectivity with students and faculty in neighboring buildings.”
In implementing the infill design, Flad Architects faced the challenge of ensuring adequate, balanced light in the space, given the adjacent, existing building wings. This was particularly important in the nuclear magnetic resonance lab and other ground-floor areas, as too much direct sunlight could harm specialized instruments.
To allow for light penetration from the fifth floor to the ground floor, the design team desired a large, central atrium. It would allow light to spill down and throughout the building to promote student well-being. One potential setback with drawing light through the atrium was meeting fire and life safety codes. The firm needed a code-approved floor to divide the shaft into two segments, and to provide a barrier to fire and chemicals in the case of an accident. However, many of the floor systems available to meet these stringent fire and life safety codes were opaque fire-stopping materials, such as concrete and corrugated steel.
Solution: To satisfy fire and life safety codes and help illuminate the infill, the design team used a fire-rated glass floor system that consisted of 2-hour fire-rated heat-barrier glass; a tempered, laminated walking-surface glass; and a steel framing grid. It is fire-rated for 2 hours and provides a barrier to flames and smoke, as well as radiant and conductive heat. During a fire, this capability ensures the glass floor system’s surface remains cool enough for individuals to walk across for the duration of its 2-hour fire rating.
“We needed a fire barrier in the atrium, but we didn’t want researchers and students to be in the dark,” says Garrett. “The fire-rated glass floor system allowed us to compartmentalize a very large volume of space without blocking off access to daylight.”
The fire-rated glass floor system used supports loads up to 150 psf (732 kilograms per square meter), which creates additional usable space in the project. The system’s textured, top-surface glass provides students and faculty with the necessary traction to walk across its surface without slipping. The use of ceramic etched laminated glass creates a mild opacity that allows the system to diffuse daylight from above the atrium down into the nuclear magnetic resonance ground-floor lab.
“The soft, milky appearance of the fire-rated glass floor system was really important from a daylighting perspective,” Garrett says. “Direct sunlight could damage the highly specialized instruments in the nuclear magnetic resonance lab. The pattern on the glass creates just enough opacity to allow for the transfer of soft, even light.”
Today, students studying on the fire-rated glass-floor system can see the shape of instruments in the lab below. At the same time, the translucent glass provides privacy from ground-floor occupants looking up toward the light well above.
“It’s great to see the students are comfortable on the fire-rated glass floor. They have no hesitation to spend time studying on it,” adds Garrett.
Photo courtesy Darris Harris | Technical Glass Products (TGP)
A fire-rated glass floor system allows for light penetration while providing critical compartmentation
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