SwRI Performs First Permeation Testing On Pipes
11 September 2000
SwRI Performs First Permeation Testing On Pipes
SAN ANTONIO--Sept. 8, 2000--Southwest Research Institute (SwRI) has expanded the scope of its permeation research facility to include the testing and study of gas pipelines. This is the first known permeation study on a tubular product that transports natural gas."SwRI's permeation test facility is capable of performing permeation research in other industries such as gas pipelines," Alex Wenzel, Director of Fire Technology, said. "The Institute has performed engineering and evaluation research for more than 50 years in the engine and vehicle research field, automotive component development, emissions and fire performance research, and durability testing."
The Institute's 2,000-square-foot permeation test facility evaluates fuel system components for hydrocarbon emissions. The facility's two mini-SHEDs (Sealed Housing Evaporative Determination) use a gas chromatograph and a flame ionization detector. A unique feature of the Institute's SHEDs is they are made of a cylindrical aluminum chamber, which allows for quick heating and cooling. The advantage of this type of facility is that it also has low hydrocarbon "hangup," which allows for more accurate results. In some chambers, there is a tendency for the hydrocarbons to become trapped in the seams and corners of the chamber causing a high hydrocarbon "hangup" and sometimes falsifies results.
"SwRI is one of the first organizations to branch outside of using a permeation facility for the automotive industry," Mike Luna, a program manager in the Fire Technology Department, said. "I think we will start seeing more of these types of tubular products being tested for permeation. This could actually affect a wide range of industries -- from water pipelines to various types of gas pipelines and anything in between."
For this particular study, the Institute is evaluating the permeation of natural gas in an underground pipeline. The concern is that if a pocket of gas builds up outside the pipe, it could become explosive if an ignition source is present.
"The study will evaluate the permeation results at certain pressures and temperatures. The material for this pipeline is a composite, which is not typically used in natural gas pipelines," Luna said. "Because this type of research has not been previously performed, we developed a test protocol and procedure to study the permeation of a gas pipeline."
The Institute's Fire Technology Department has performed permeation testing for the past two years. Approximately 10 years ago automotive manufacturers began using plastic fuel tanks rather than metal, and the problem of gasoline vapors permeating through the walls of the plastic tanks became a concern. Because of strict emission regulations from the Environmental Protection Agency and the California Air Resources Board, the overall emissions from a vehicle are closely monitored. Luna said permeation testing for the automotive industry encompasses fuel tanks, fuel pipes and any other plastic automotive component that may contain fuel.
SwRI's permeation facility also holds a pressure/vacuum station, for test cycling from a certain pressure to vacuum, and a slosh table station, for sloshing the fuel during rigorous cycling and testing for any material failures. Each of the mini-SHEDs in the permeation facility can endure a temperature range from -30 degrees F to 180 degrees F.