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August Newsreel: Stimulus boosts smart metering, Indiana tunnel prevents sewage overflow and more
"Pipelines that deliver clean water and remove wastewater are essential to the well-being of our communities," said Tucker. "Some utilities may have only one source – one lifeline – into a community. In areas of seismic activity, utilities need to consider how best to protect these lifelines from failure."
The study reviewed data about pipe failures during modern-day earthquakes, including the following earthquakes in the U.S.: Prince William Sound, AK, 1964; Loma Prieta, CA, 1989; and Northridge (San Fernando Valley), CA, 1994.
"Earthquakes like these have demonstrated time and again the need for high-strength, flexible pipe with flexible joints," Tucker said. "Whether the pipe and joints are flexible or rigid determines the ability of the pipeline to resist the motion and energy associated with earthquakes."
The study shows that ductile iron pipe and joints performed the best, sustaining only minimal structural damage. Asbestos-cement pipe had the worse failure rate and plastic pipe was more likely to pull apart at the joints.
"Most mid- to large-size utilities in seismic zones in this country use ductile iron pipe and joints designed for river crossings," Tucker said. "This application has proven very effective in withstanding the effects of earthquakes. It uses locking joints with 15 degrees deflection."
Other utilities, in particular small rural utilities, should take a close look at their systems.
"Utilities in seismic zones need to evaluate the lifelines critical to their systems and give these lifelines top priority for retrofitting or replacement to ensure the greatest seismic resistance," Tucker said.
Researchers calculate the cost of CO2 emissions, call for carbon tax
Rice University’s (Houston) Baker Institute for Public Policy study urges policymakers to support shift from coal to natural gas
Two Rice University researchers are calling on policymakers to encourage the transition from coal-based electricity production to a system based on natural gas through a carbon tax.
Such a mechanism would help limit carbon dioxide (CO2) emissions. At the United Nations Climate Change Conference in Copenhagen last December, the United States pledged to reduce the 2005 levels of CO2 emissions by 17 percent by 2020.