the Need To Know: April 14, 2001, Page Three

AUTOMATIC GAS SHUTOFF VALVES

For those who want to think about as few details as possible or if you live in an area that has frequent earthquakes, an automatic gas shutoff valve might be worth considering. This is an excellent gadget if you're frequently away from home and live in a quake-prone zone.

The basic purpose of a gas shutoff valve is to cut the flow of gas to your house in the event of an earthquake. These units are installed between the gas meter and your home. Each device has a simple mechanism inside which, when activated, blocks the flow of gas. Different manufacturers have their own unique methods of restricting gas flow, but they all operate essentially the same way.

For earthquake purposes, be sure to purchase a seismic valve as there are two types: seismic valves and excess flow valves.

Seismic valves are triggered by the ground shaking caused by earthquakes. When shaking reaches the level of the valve's designated shutoff point (people generally set them around 5.2-5.4 on the Richter Scale), the valve automatically stops the flow of gas into your house. Once you have determined there is no potential danger from fire or explosion, reset the valve manually to restart the flow of gas.

Shutoff valves are generally made from cast aluminum and come in various sizes fo fit 3/4", 1", and 1-1/4" pipe.

PROPANE TANKS

During an earthquake a propane tank can be knocked off its legs posing the danger of fire or an explosion. Even if it stays on its legs, jostling can rupture the tank setting the scene for a fire. The same caution applies for small tanks like those use for BBQs and camping.

One way to prevent damage to propane tanks and compressed gas cylinders is to anchor and brace them securely. This figure shows how the legs of a propane tank can be braced and anchored. Using a flexible connection on the supply line will help reduce the likelihood of a leak. Compressed gas cylinders, because they have to be periodically replaced, cannot be permanently anchored. You can use chains to attach them to a wall so that they'll remain upright. Before altering your propane tank: 1. Make sure you own the tank. Some utility companies only rent these units. 2. Empty the gas before doing any welding. 3. Check with your propane supplier for any other safety precautions.

Clear the area around the propane tank to ensure that there are no tall or heavy objects that could fall on the tank or rupture the supply line.

Keep a wrench near the shutoff valve and make sure family members know where it is and how to turn off the supply line if they smell a gas leak. This is another reason to consider installing an automatic gas shutoff valve.

Using a flexible connection between the propane tank and the supply line and where the supply line enters the house is a good idea. This should be done by a licensed contractor both for safety and to make sure it meets to codes.

Attach compressed gas cylinders to a wall, using two lengths of chain around the cylinder -- one just below the top of the cylinder and one just above the bottom. The chains should be secured to eye hooks screwed into the wall. In wood-frame walls, the eye hooks must be mounted to studs. In concrete or masonry block walls, install the eye hooks with expansion anchors or molly bolts.

SHUTTING OFF THE WATER SUPPLY

If you know there are leaks after an earthquake, you can shut off all the water in your house. Locate the main water service pipe into your house (probably in the front at the basement level or near the street or sidewalk). Many water utilities set their meters and shutoff valves into a shallowly buried concrete case. Open the cover with a long screwdriver or specialty tool. There will be a gate valve on the pipe. The valve can be operated by a water main wrench or crescent wrench. If this box is inaccessible or you can't find it, call your water department. Paint the valve so it's easy to find in an emergency.

It's a good idea to locate it before an emergency.

If your box is buried deeply or set into a berm, you may need to purchase a long handled water main wrench from your local hardware store. They cost about US$15 - 25. Even if your water main shut off is easy to reach, these wrenches make the job easier.

Don't let the word "wrench" throw you when looking for this item. These wrenches come in varying lengths, typically four or five feet, and resemble a steel pipe about 1-1/2 inches in diameter.

ADDITIONAL HELP

Two other free sources of information for protecting your home can be found on the Internet.

San Leandro's (California) award winning guidebook describes easy and low-cost ways to make your home safer in earthquakes. 3 Easy Low Cost Ways To Make Your Home Earthquake Survivable can be download in its entirety in PDF or choose certain sections. This 16 page booklet has excellent photos which clearly illustrate what to do. http://www.abag.ca.gov/bayarea/eqmaps/fixit/training.html

FEMA has funded the development of materials to train contractors and building inspectors on how to perform common earthquake retrofits for single family homes. Don't let it frighten you that the material is for contractors. Most handy people should be able to understand the information since it's training material for these folks.

Included are both a manual and a slide presentation. The ENTIRE Manual is available as Adobe Acrobat files, and via ftp as MS Word files. The slide presentations are available as html presentations, and via ftp as PowerPoint files. http://www.abag.ca.gov/bayarea/eqmaps/fixit/training.html

Another helpful web site is the Home Building Manual with this very useful Construction Glossary http://www.HomeBuildingManual.com

SCRUMPTIOUS SKIES - AGAIN!

Maybe as a kid I wasn't looking up often enough or else lived in the wrong place, but do you remember seeing auroras this frequently in so many locations around the world and in these gloriously vivid hues? They make NBC's peacock look like an ugly duckling! Right on the heels of April 11th geomagnetic storm, we have yet another CME hurtling toward Earth. This CME rocketed out of an X2 class flare and the resulting storm should impact Earth today, Saturday. Like last week, people living in latitudes higher than ~50^o should have the best viewing. However, this stunning photo (right) snapped by Chris Grohusko, near the New Mexico - Texas border is remarkable since it shows the auroras dipped much lower than expected. Maybe they will this week too. Click photos below for larger image Garth Arsenault, Prince Edward Island, Can. April 11, 2001 Harald Edens, Wijdenes, The Netherlands April 11, 2001 Thad V'Soske, Anza-Borrego Desert State Park, s. California April 11, 2001 Morton Henderson, Glasgow, Scotland April 12, 2001