ROANOKE TIMES
Copyright (c) 1996, Roanoke Times
DATE: Tuesday, March 5, 1996 TAG: 9603050079
SECTION: EXTRA PAGE: 3 EDITION: METRO
COLUMN: At Home with Technology
SOURCE: DAVID BUTLER
Q: A friend of mine is building a new house that he says will have natural gas "convenience outlets" and a new type of gas plumbing system. Do you know what he's referring to?
A: A gas convenience outlet is a special valve with an easy connect-and-disconnect feature. Gas appliances connect to these outlets with a flexible hose rather than a rigid pipe. Disconnecting a gas appliance such as an outdoor grill is as easy as unplugging an electric appliance. Additional outlets can be installed at locations where gas may be needed in the future.
For safety's sake, gas convenience outlets have a mechanical interlock that prevents the flow of gas unless the appliance is properly connected. Although quick-connect outlets are common in commercial kitchens, residential models have only recently been introduced.
Quick-connect outlets may eventually lead to a new generation of "plug-in" gas appliances for the home. In Japan, consumers enjoy the convenience of portable gas products such as rice cookers. Maybe someday a countertop gas burner unit will be approved for sale in the US. I long ago gave up trying to convince my wife to part with her electric range.
More dramatic innovations are taking place behind the wall. Flexible gas lines made from corrugated stainless steel tubing (CSST) represent the state of the art in residential gas plumbing. As with gas convenience outlets, CSST is widely available in Japan where it enjoys a good performance and safety record.
In the US, flexible steel piping was accepted by The National Fuel Gas Code in 1988. It has already been incorporated into local building codes in many areas of the country.
Flexible CSST is much easier to install than traditional "black iron" pipe. The plastic-sheathed tubing can be snaked through walls and under floors in long continuous runs - much like electrical wiring. Black iron pipe, in contrast, requires heavy-duty tools for cutting and threading, as well as bulky fittings for each joint and corner.
Although CSST is made from steel, it's extremely light - one person can easily handle a 250-foot roll! As with electrical wiring, metal strike plates are used to protect CSST where it passes through studs. Between studs, a direct nail strike will push the tube harmlessly to one side or the other.
In contrast to the "trunk-and-branch" design of rigid plumbing systems, CSST is laid out in "home run" fashion: Each appliance connects directly to a distribution manifold. Each outlet (port) on the manifold has a shutoff valve. There's no need to close the main supply line when disconnecting or servicing a gas appliance. This is roughly analogous to turning off an electrical circuit breaker.
From a materials standpoint, CSST components cost more than black iron pipe. And though prices continue to fall as CSST gains in popularity, it will always be more expensive than black iron. But that's not the whole story. In most cases, the labor savings offsets most (if not all) of the difference in materials cost. CSST is so easy to install that one plumber can pipe a new home in a day or less!
Flexible piping is particularly attractive for retrofit projects. With rigid plumbing, adding natural gas service to an existing home can be both expensive and time consuming. It often involves cutting into floors, walls or ceilings. With CSST, ancillary damage is kept to a minimum.
To receive a list of companies that manufacture flexible gas plumbing components and convenience outlets, please send $1.50 and a self-addressed envelope to David Butler F-602, Department TWN, 14713 Pleasant Hill Road, Charlotte, N.C. 28278-7927. The list includes toll-free phone numbers and a summary of each company's products. You'll also receive information on some of the latest innovations in gas appliances.
Tech talk
Use the following factors to convert between natural gas and liquid propane: Natural gas has 1,000 to 1,200 BTUs per cubic foot and is usually sold in "therms" (100 cubic feet). This means a therm possesses between 100,000 and 120,000 BTUs, depending on the source. Propane, usually sold by the gallon, has 91,500 BTUs per gallon. A gallon of propane weighs 4.344 pounds and occupies 36.8 cubic feet.
LENGTH: Medium: 82 lines ILLUSTRATION: GRAPHIC: Flexible tubing offers many advantages overby CNBconventional iron pipes. The additional cost is offset by savings on
labor.