Great Glazing: San Francisco Public Utilities Commission, fire-rated glass stairwell

The basics: The new 277,000-square-foot San Francisco Public Utilities Commission building is slated to achieve a LEED Platinum rating from the United States Green Building Council, due in part to its daylight harvesting. As part of the daylighting design, the building incorporates a fully transparent, interior, two-hour fire-rated glass stairwell enclosure that spans 14 floors. The stairwell’s transparent design allows daylight coming in the through the building’s all-glass exterior to further penetrate the interior, illuminating the space with natural light and eliminating the use of electricity. At times when artificial light is needed, the glass allows shared artificial lighting between spaces, minimizing the electricity load.

The players: Architect: KMD Architects; general contractor: Webcor Builders; insulating glass and interior door supplier, Hartung Glass Industries; fire-rated glass and framing supplier: Safti First; contract glazier: Progress Glass.

The glass and framing: To meet ASTM E-119/NFPA 251/UL 263 requirements, the fire-rated stairwell walls use SuperLite II-XL 120 in GPX Framing from Safti First. The doors leading into the stairwell feature Safti’s SuperLite II-XL 90 in HMTR Framing.