Author Archives: CS Editor

Fire-rated Glass Floor Captures the Light at Northwestern

At Northwestern University, this fire-rated glass floor provides a barrier to flames and smoke, but offers daylighting and a unique look. Photo courtesy Technical Glass Products

At Northwestern University, this fire-rated glass floor provides a barrier to flames and smoke, but offers daylighting and a unique look. Photo courtesy Technical Glass Products

Located in Evanston, Illinois, Northwestern University’s Engineering Life Sciences infill is a bright, multi-disciplinary 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 Silver standards under the U.S. Green Building Council’s (USGBC’s) Leadership in Energy and Environmental Design (LEED) program.

“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 (NMR) 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 that met these stringent fire and life safety codes were opaque fire-stopping materials such as concrete and corrugated steel.

To satisfy fire and life safety codes and help illuminate the infill, the design team used a fire-rated glass floor system comprising:
● two-hour fire-rated heat barrier glass;
● tempered, laminated walking surface glass; and
● steel framing grid.

It 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 two-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 supports loads up to 732 kg/m2 (150 psf), 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. Use of ceramic-etched laminated glass means mild opacity, allowing 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,” says Garrett. “Direct sunlight could damage the highly specialized instruments in the NMR 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.

New InterSpec website launched

Building information modeling (BIM) integrated specification software InterSpec has launched a redesigned website with design professionals in mind. The new site offers individual landing pages for each sector of the industry, featuring specific information, resources, and easily accessible e-SPEC information. Compatible with various browsers and mobile devices, users can watch online demos, register for webcasts, or request previously recorded presentations. They can also access product release information in the news section. Visit

Seismic design publications released

The Vibration Isolation and Seismic Control Manufacturers Association (VISCMA) have released two documents for HVAC engineers. “Attachment of Sheet Metal Curbs to Roof Decks” examines the frequently overlooked design challenge of attaching seismically rated sheet metal curbs to structures. The resource addresses the assumption that an attachment will carry only the combination of a weight load and horizontal shear load generated by seismic forces. Secondly, “VAV Boxes and Small HVAC Component Restraints” outlines up-to-date technologies as defined by building codes. It examines terminal units and other small HVAC components in buildings that require seismic restraints. Visit for more information.

PCRs and EPDs now available

The Builders Hardware Manufacturers Association (BHMA) has published product category rules (PCRs) for locks, latches, exit devices, door closers, and hinges. This sets the framework for manufacturers to develop environmental product declarations (EPDs), which increase transparency and help design professionals compare components. PCRs identify the rules and requirements for lifecycle assessments (LCAs), and are important for EPDs under International Organization for Standardization (ISO) 14025, Environmental Labels and Declarations: Type III Environmental Declarations−Principles and Procedures. These PCRs were developed with Underwriters Laboratories’ (UL’s) expertise. The document is now available for download at

Specialty cable and wire guides published

The Copper Development Association (CDA) has released two publications offering information on installing copper wire and using speciality cables to meet requirements and codes. Available on the group’s website free of charge, Recommended Practices for Designing and Installing Copper Building Wire Systems examines various aspects of design, installation, and maintenance practices for copper conductors and wires. The topics covered include electrical system cost and efficiency, fire-resistive cable systems, and temperature effects on wiring systems. The second document, Specialty Cables, outlines the benefits of using specialty cables in certain applications. For example, mineral- and polymer-insulated cables are discussed in terms of commercial and industrial applications, or even for use in transportation vehicles. This guide will assist design professionals in specifying these cables. Both publications are available at