Let There Be Light: Fire Rated Glass Floor Brings Vision and Transparency to Union Square Station

June 1, 2022 KEYWORDS fire resistance Order Reprints No Comments ✕

A well-thought out and executed design is important for any project to succeed, and this is more critical than ever when designing transit centers. First and foremost, the design has to be functional. Transportation terminals have to efficiently move thousands of people, incorporating advanced technologies, wayfinding techniques and safety.

Because it is also a symbol of the community, aesthetics plays a significant role as well. “One of the greatest opportunities to introduce and embed the character and brand of a city is through smart design of Transit Centers—from the architecture, materials, colors, to its wayfinding, signage, and physical and virtual digital interconnects with the world,” says Philip Lenger in his article Transit Design: Brand of a City. “Just as Ellis Island and the Statue of Liberty did in the late 1800s, transit centers become the cornerstone gateway branding for a modern city today.”

These concepts ring true for the upcoming Union Square Station in San Francisco. According to the SFMTA’s website, this new station will “connect residents and visitors to this vibrant urban center, home to the city’s highest concentration of jobs and an outstanding array of hotels, retailers, and restaurants.” Scheduled to open later in 2022, the station includes an underground concourse that leads commuters directly to the Powell Street station, where they can easily link with BART and other Muni Metro lines.

Because of this station’s prominent location, the architects ensured that the design would not only be functional, but that it also provided an artistic statement fitting this well-known San Francisco busy hub. According to David Fung of Robin Chiang & Company and project architect for Union Square station, incorporating light and transparency were very important in the design. To achieve that, a 2-hour glass floor with a decorative walkable surface was specified. According to Fung, this statement piece will “provide daylighting to cheer up the station entrance, enforce visional connection between Union Square Plaza and the station entrance, and create an additional activity space that incorporates artwork.” In addition, the 2-hour glass floor would also serve as a lightwell to improve wayfinding by welcoming commuters into the expansive underground concourse level.

Sharon Heagney, VP of Engineering and Project Management at SAFTI FIRST, met with the project team to discuss project specific details and address any material questions they had. “We provided various samples that they could analyze and ultimately select the ones that would provide them with the high definition they were looking for. We also assisted them in other areas such as structural attachment, water proofing and overall layout,” says Heagney.

Click to enlarge.

SAFTI FIRST provided its GPX FireFloor System, a complete fire-resistive glass and framing assembly that meets ASTM E-119/UL 263 up to 2 hours. It features a modular, top-loaded design for easy installation. Both fire-resistive glass and fire-resistive structural frame were manufactured in SAFTI FIRST’s world-class facilities in Merced, CA.

At a little over 1,000 sq. ft., the fire-resistive glass floor brought in light and openness desired while providing maximum protection against smoke, flames and radiant heat required by code. Listed by UL and Intertek, the GPX FireFloor System has the largest tested and listed individual glass panel sizes in the market today—easily accommodating the 23 sq. ft. panels for Union Square Station, which were also butt-glazed together for a more seamless design (the 2-hour GPX FireFloor System has a maximum individual panel size of 49.86 sq. ft. in both fully captured and butt-glazed applications). It was designed with a small slope for water drainage off the floors and into the gutters.

The GPX FireFloor System for Union Square Station featured a custom, decorative walkable surface. The artwork for the glass floor was a commission to Hughen/Starkweather, a collaborative team comprised of San Francisco artists Jennifer Starkweather and Amanda Hughen. The walkable art surface for this was provided by Pulp Studios in Los Angeles, and then laminated into a single fire-rated two-hour floor panel in SAFTI FIRST’s facility.

Heagney’s team also worked with Tutor Perini, the general contractor, and ACR, the glazing contractor. “Coordination with other trades was also key as the art glass had to line up perfectly piece to piece to ensure that the overall image was achieved,” adds Heagney. As a local manufacturer, SAFTI FIRST was also able to provide other accommodations including adhering to tight lead time that avoided delays, as well as being able to meet with the installer onsite to answer any questions that they had.

In addition to the 2-hour glass floor, SAFTI FIRST also provided the fire-rated glazing and framing for the 2-hour glass elevator enclosures using SuperLite II-XL 120 in GPX Architectural Series Framing. This provides visitors with an open and airy feeling while traveling below ground then through the station to reach the station’s platform. Each level is connected by SAFTI FIRST’s clear decorative fire-rated glazing to continue this airy artistic feeling with light flowing down through each floor. “The elevator cabs and enclosures are mostly glass to provide safety and security passengers,” says Fung.

All the fire-rated materials SAFTI FIRST provided to this project met the Buy America Act required by the government for transportation projects with federal involvement. “We appreciate any opportunities to showcase USA-made products and systems in our design projects,” adds Fung.

“Union Square is a San Francisco landmark,” says Heagney. “Being that SAFTI FIRST began in San Francisco over 40 years ago, we are all very proud that we could be a part of a special project in our own backyard that will be used by millions of people for generations to come.”

 

Project Name: Union Square Station in San Francisco, CA
Architect: Robin Chiang & Company
General Contractor: Tutor Perini
Glazing Contractor: ACR
Products Used: GPX FireFloor System for the 2-hour glass floor; SuperLite II-XL 120 in GPX Architectural Series Framing for the 2-hour elevator enclosures