Why Your Home Needs a Seismic Gas Valve

As Southern California took stock of the damage following the 1994 Northridge earthquake, it quickly became clear that a significant amount of it was due to gas explosions and fires. Some water heaters launched up to 30 feet from their original positions. Although the 1906 San Francisco quake is harder to investigate from over 100 years distant, it appears that a large part of the destruction was also the result of gas_fed fires.

California now has a law on the books mandating that water heaters be strapped into position in all homes being sold. Although the state supplies directions on how to properly do this, there is no double_checking or enforcement provision, so buyers are forewarned to check on this personally (and be able to know right from wrong). The City of Los Angeles passed a law, which state legislators are attempting to use for a state_wide model, that requires automated seismic shut_off valves on gas lines of homes being sold. Allstate and other insurance companies are considering such a requirement for their policyholders, too, and cities and states around the country are considering their own laws. Any well_informed homeowner, it would seem, should need no encouragement to take such a smart, proactive, defensive move. When you understand why your home needs a seismic gas valve, you are quite likely to get one, and fast.

More than quakes
Although it is the earthquake that most occupies the imagination of California homeowners, there are other natural and unnatural occurrences in which the shut_off valve can save you and your property. Besides quakes, there are weather events (tornadoes, hurricanes, etc.) that can batter homes into kindling, and seismic shut_offs valves will respond to these devastating forces, too. With a combination of various defensive measures, including these devices, homeowners in any part of the country can protect themselves against a wide variety of natural events. Seismic valves and other defenses will also protect against unnatural (or human_caused) ones, such as utility explosions or accidents wherein vehicles crash into gas lines or garages.

In fact, some cities are crafting their laws to address the possible consequences of various actions, rather than specify the causes to be defended against. Progressive communities in the San Francisco Bay Area are taking the lead in this area. The technology used in gas shut_off valves has to be approved by the state of California, but cities are free to add other requirements to prevent fires and explosions from utilities, power lines, chemical storage and other things. The reasons are clear, of course. It is to protect not only the individual homeowner, but also the community as a whole, since the spread of fires is the cause of most devastation in both quakes and weather_related catastrophes.

How they work
Seismic shut_off valves come in two major types, a seismically_activated kind that reacts to shaking forces and one that detects excess gas flow. The first kind typically has a ball resting in some sort of socket, and is engineered for the ball to fall out when a quake of 5.4 or over (Richter scale) occurs. This releases or initiates a mechanism to close the valve, and is a fairly simple design that is efficient and inexpensive to manufacture. Most of these kinds of devices have a simple reset device of some kind, and turning them with a small screwdriver can turn your gas back on.

The first type usually contains a ball that rests in a socket of some sort. When shaking hits 5.4 on the Richter scale, the ball falls out and a mechanism of some sort triggers the valve to close. It's actually very simple.

Most of the valves sold today have some sort of reset device built right onto the valve so that you can take a little screwdriver and turn your gas back on. Be sure to get help and check the whole house thoroughly, including the crawlspace at the time to reactivate the gas. Utility reps will be in short supply so you'd best be able to do this yourself after we've had a quake.

The second type is designed to sense breakages in the piping. When we run the stove and the water heater and the dryer, we still only allow for a limited rate of flow through the main pipe. When a pipe breaks completely, the flow will be greater than that and this is what these valves sense. When this occurs they plug shut. It is another simple mechanism that involves a spring loaded plug that requires enough wind to drag to the shut position. I don't favor these for us due to the fact that you can get many small breaks in your gas piping and not set them off. When an earthquake occurs, a seismically activated valves will go off regardless of the size or number of leaks created.

There are a number of valves that are approved and most are quite cheap (mostly under $100). The Little Firefighter is a favorite of mine, although I also like the Northridge and the Vanguard. You can search them online and you can also check out our own Berkeley supplier, gasvalvedoctor.com. Boaz Levanda (843_3275) is a nice chap who'll be happy to sell you one. He has also been a one_man legal squad trying to get the permit requirements reduced so that they can be installed for fewer bucks.

A plumber is the right person to install such a device and the cost seems to be around $200_$300 for installation (plus the valve). It's usually quite simple but can be more complex in some cases. If you're in a condo or apartment complex, you'll need one for each unit.

So, if you have only $300 or $400 to spend on earthquake preparedness and do not want to put a single bolt into anything, please, oh please go get one of these.Overland Plumbing has been a leader in quality emergency plumber los angeles for over 20 years - we do the job right the first time, with the right tools, the most advanced equipment, and the most responsive customer service in the industry.