In the aftermath of this winter’s slew of storms breaking high-rise windows and blowing panels off buildings, the SF Board of Supervisors is learning that many of the broken windows may be from the same manufacturer.

The winter 2023 San Francisco storm season phenomenon of windows and panels flying off buildings started early in the year with a January 4 incident where a glass window flew off of Fox Plaza at Civic Center, likely due to high winds. More wind storms in February ripped metal panels off the SF PUC building. And then in March’s batch of wild storms, we saw a glass panel fly off 555 California Street, a window falling off the perpetually troubled Millennium Tower, and a Mission and Fremont Street office building suffering two broken window incidents within a week.

“As if the sea level rise and orange skies weren’t enough, last month over the course of a couple of weeks, the windows in seven different downtown buildings failed, raining glass down onto the sidewalks below,” Supervisor Aaron Peskin said while introducing new façade inspection legislation at Monday’s SF Board of Supervisors Land Use and Transportation Committee meeting.

“The only miracle here was nobody got seriously hurt,” he added. “People could have been killed.”

These windows are supposed to be able to survive hurricane-force wind gusts of up to 120 miles per hour, yet failed in winds that were nowhere near that strong. Peskin brought up a theory into why so many windows, even in buildings less than ten years old, broke or flew off in the high winds.

“I have heard, anecdotally and it is yet to be proven, that all of the three modern buildings where the glass failed, they were all produced by the same manufacturer,” Peskin said Monday. “So there may be impurities in the glass.”

A 2016 amendment to the existing San Francisco building code required Department of Building Inspection façade inspections to be completed by the end of 2021 for the city’s oldest high-rise buildings that predate 1910 (and there are actually 214 of those!). By that amendment, buildings completed between 1910-1926 had their façade inspections required to be finished by the end of this year, with successive cohort requirements going forward by the building's age. Buildings completed after 1998 wouldn’t require façade inspections for another 30 years.

That assumed age was the main factor in window failures. But we learned during this year’s storms that assumption may not hold true — Millennium Tower was certified for occupancy in 2009, the 350 Mission that had two busted windows was certified in 2015, a 1400 Mission Street building where windows broke was certified in 2016.

Peskin’s proposed legislation would currently add a requirement that buildings completed after 1998, and 15 stories or taller, would be required to produce façade inspection reports by November 1, 2023 (e.g., the beginning of next winter’s storm season). Peskin said 71 buildings meet this criteria. Not all of them are office buildings, many are condos and apartment buildings. The Land Use and Transportation Committee voted to reconsider the legislation next week, with a chance to field more information from the Department of Building Inspection over the next seven days.

Related: Windows Flying Off SF High-Rises Freaks Out City Hall, Beefed-Up Regulations and Inspections On the Way [SFist]

Image: @BrokeAssStuart via Twitter