When a private media lab in Massachusetts recognized the need for additional research space to continue pushing the bounds of innovation, it envisioned a facility where design and technology converge. The transfer of abundant daylight was central to creating the imaginative physical space. One project setback was figuring how to effectively stream natural light from the building’s skylight through the sixth floor and down into the central atrium below, while meeting two-hour fire-rated codes.
Commonly specified floor systems like concrete would meet the horizontal separation’s stringent fire and life safety codes, but block light. The material’s opaque form would prevent diffuse daylight from filtering throughout the building. The media lab’s solution was a custom, fire-rated glass floor system, referred to as the ‘light well.’
The specified fire-resistance-rated glass floor system is impact resistant, approved for loads up to 732 kg/m2 (150 psf), and fire-rated for up to two hours. During the day, it transfers diffuse sunlight from the above skylight to an atrium 10 m (35 ft) below. The atrium extends through the third, fourth, and fifth floors. It allows natural light to pass down into areas incapable of otherwise receiving sunlight from above.
The fire-rated glass floor system also incorporates a layer of protection sandwiched between two, 12-mm (0.5-in.) clear, tempered layers of glass, making the system translucent rather than transparent. The transparent interlayer provides individuals walking on the sixth floor with privacy from any occupants below. Depending on the selected interlayer or walking surface properties, the fire-rated glass floor system’s translucency can range from fully transparent to nearly opaque. Manufacturers and suppliers can provide the specifications to indicate an interlayer’s visible light transmittance, helping ensure both privacy and light transfer project goals are met.
By night, lights from the fifth-floor ceiling illuminate the floor’s translucent surface. They transform the floor into an elegant focal point, and create a sense of imagination and creativity extending into the evening hours.
An infill solution
While it is growing increasingly popular to use fire-rated glass floor systems to harness natural light in innovative ways, as evidenced in the private media lab, some design teams require the assembly to do significantly more. A case in point is the Northwestern University’s Engineering Life Sciences infill in Evanston, Illinois.
When Flad Architects was tasked with bridging two of the campus’ existing building wings to meet the need for more space, it faced the challenge of providing students with ample access to daylight. The catch was that the light needed to be balanced. Too much direct sunlight could harm specialized instruments in the nuclear magnetic resonance lab and other ground floor areas.
The desired solution was a large, central atrium that would allow soft 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 case of an accident.
To satisfy fire and life safety codes and help illuminate the infill, the design team used a fire-rated glass floor system.
“We needed a fire barrier in the atrium, but we did not want researchers and students to be in the dark,” said Matt Garrett, project architect at Flad Architects. “The fire-rated glass floor system allowed us to compartmentalize a very large volume of space without blocking off access to daylight.”
Keeping in mind the additional need for balanced light transfer, the firm specified the fire-resistance-rated glass floor system with ceramic-etched laminated glass. It 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,” explained Garrett. “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.”
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 portal 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,” added Garrett.