Some building inspectors have reportedly been sounding alarm bells for years about an issue that is likely not familiar to most San Franciscans, but one that could become the central oversight blamed in a future disaster. And several SF supervisors now say that they need to look further into this before such a disaster occurs.
The problem is this: The City of San Francisco demanded back in 2014 that owners of all buildings with a so-called soft story on the ground level — i.e. a story of open space, like a garage, over which a multi-unit building sits, creating a seismic issue because of the lack of direct contact between the dwelling space and the foundation — retrofit those buildings by 2021. In recent years, you may have seen ground-floor businesses like restaurants have to temporarily close while this work takes place. As of recently, some 4,000 out of 4,900 tagged buildings have undergone a retrofit.
But, as Mission Local reported last week, many contractors have poured new concrete foundations that encase old gas pipes — pipes that had previously entered buildings through sand. Inspectors say the pipes could be more prone to rupture from earthquake shaking due to the concrete around them, potentially causing what one inspector said could be a San Bruno-like catastrophe.
Bay Area residents who've lasted more than a decade will remember the infamous, tragic San Bruno blast in 2010, in which a high-pressure PG&E gas main ruptured underneath a residential neighborhood south of San Francisco. The literal towering inferno that was caused, with a powerful hose of fire shooting hundreds of feet into the air, killed eight San Bruno residents, injured over a hundred others, and destroyed over three dozen homes.
It's unclear, though, to what degree this is hyperbole and to what degree there are high-pressure gas mains like the one ruptured in San Bruno running under San Francisco homes, or through these new concrete foundations.
Steve Panelli, the Department of Building Inspection’s chief plumbing inspector, is the one who tells Mission Local that the danger is real, and these are high-pressure lines, and "If one little leak happened and something happened here — it becomes catastrophic now."
It's also not clear how widespread the problem is — some building inspectors have reportedly ordered this problem to be corrected, which can apparently be done by cutting a one-foot gap in the concrete around the incoming gas pipe. But reportedly some contractors have taken shortcuts, and haven't always been caught.
Now, as Mission Local reports in a follow-up, three SF supervisors are disturbed enough to call for hearings.
Supervisor Myrna Melgar, who previously worked in the Mayor's Office of Housing, tells Mission Local that "not all of these allegations are new." But, she added, "If what these articles shed light on is true, then we are in deep shit — and we have to take corrective action."
Supervisors Aaron Peskin and Hillary Ronen concur, with Peskin telling Mission Local, "Public safety is the most important issue and we need to figure out what needs to be done to ensure we don’t have life-safety issues. That is going to require an independent analysis and may require jackhammers and money."
Structural engineers who are part of a regional association claim to Mission Local that they've raised the alarm at SF DBI about shoddy construction and other problems with these retrofit projects, but they were brushed off.
It's not clear still when or if a hearing will occur on this issue, but Melgar says it will be an "open and transparent process," and she's eager to look into the history of the problem.