Do you know where your natural gas shutoff valve is? Are you going to need a wrench to turn it off? If the ground starts shaking and the ceiling is coming down on your head, are you going to be thinking about your pipes cracking and spewing high-pressure, flammable natural gas into your home?
Probably not, which is why automatic shutoff valves were developed. They trip and kill the gas flow to the pipes inside your house when seismic activity is greater than 5.2 on the Richter scale.
Right now, the city puts its faith in citizens to be ready to kill the gas if the big one hits. Not all cities agree with this policy. After the Northridge earthquake in 1994, Los Angeles passed an ordinance mandating automatic shutoff valves in all new construction and for home repairs greater than $10,000. Alameda, Contra Costa, and Marin counties have similar legislation, as do the cities of Pittsburg and Hercules. Why not earthquake-prone San Francisco?
That's the question being explored by the city's Department of Building Inspection (DBI). But there are other questions too: if San Francisco decides to make a policy requiring automatic shutoff valves, can they be installed more expeditiously than the 11 years and counting it has taken Los Angeles?
DBI staff, building inspection commissioners, and city officials from the Fire Department and the Office of Emergency Services held an initial Aug. 30 meeting on the issue, and though it's too early to tell how San Francisco could mandate installation of these valves, the sentiment was that the status quo strategy of public education is not enough. The discussion also revealed some key questions about where exactly the valves can be installed, who is responsible for them, and who's going to pay.
In San Francisco there are currently two ways the gas can be shut off when there's a leak: either Pacific Gas and Electric Co. or the customer can do it. PG&E provides manual shutoff valves at all installations, but they can be difficult to operate, especially for a disabled or senior citizen.
PG&E officials say they don't have a position when it comes to recommending whether automatic shutoff valves should be installed.
"Because we serve such a large, diverse customer base, our position is a neutral position. We do not support or not support installation of these devices," PG&E's Paul Brooks said at the meeting.
Brooks, a senior gas engineer for PG&E, said the company has manual valves for the main gas lines but confirmed that there is nothing in the system that trips automatically during an earthquake. PG&E is responsible for the health of the pipes up to where they meet the meter, after which the customer is liable.
PG&E has been replacing old pipes throughout the city with polyethylene lines, which are designed to flex more before snapping when the ground shakes. In some places, the new pipes allow for gas to be delivered faster, at a much higher pressure. That's a problem, says Building Inspection Commission president Debra Walker, who's concerned about the danger of higher-pressured gas being piped into people's homes.
"We have a unique situation here in the city because of our property lines," she told the Guardian after the meeting. In San Francisco, it's common to construct buildings right up to the lot lines, milking every inch of property and making it necessary to put gas meters, gauges, valves, and gas pressure step-downs underneath the structure.
"A lot of these gas lines go into the building before the step-down. The problem and the risk are already in the building," Walker said. She argues that automatic shutoff valves should be placed farther up the line and PG&E should assume some responsibility for the installation.
Only PG&E could install them. Since 2002, the California Public Utilities Commission (CPUC) has disallowed customers from installing automatic shutoff valves on the gas company's side of the meter.
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