DENVER—A Colorado-based expanded polystyrene (EPS) foam manufacturer says research from a U.S. university shows surrounding pipelines with geofoam can help mitigate the risk of damage during seismic activity.
Geofoam, a lightweight geotechnical product, has the ability to reduce the force on underground piping—particularly high-pressure gas lines—by up to four times the amount of force as a pipeline covered with conventional soil backfill, according to ACH Foam Technologies, citing research out of the University of Utah.
“If they rupture and ignite, you essentially have a large blowtorch, which can be catastrophic,” University of Utah associate professor of civil engineering Steven Bartlett said in a release.
Bartlett and his team have been examining geofoam’s mitigating effects on pipelines from seismic faulting since 2007.
“During the summer of 2007, Questar Gas Co. requested that the University of Utah evaluate a conceptual EPS geofoam cover system for a steel, natural gas pipeline crossing the Wasatch fault in the Salt Lake City valley,” Bartlett said.
“The fault rupture is expected to produce an earthquake with a potential magnitude of 7.5 and several feet of potential fault offset at the pipeline crossing.”
Many buried pipelines are found six to eight feet below the surface.
According to ACH, Bartlett and his team showed that a pipeline protected with a lightweight geofoam cover could withstand the fault offset and reduce the force on the pipe by up to four times the amount of force as a pipeline covered with conventional soil backfill.
When the 60-kilometre section of natural gas pipeline had to be replaced between Coleville and Ogden, Utah, approximately 20,000 cubic feet of ACH-produced geofoam was used to reduce movement, shears, axial forces and strains imposed on the pipeline.
The foam was manufactured at ACH’s plant in Murray, Utah, one its eight facilities throughout the U.S.
“Geofoam has a low mass density, which reduces the vertical and horizontal stresses on buried utilities and compressive soils,” ACH’s geofoam expert Terry Meier said.
“This reduction in loading and deformation will likely improve the performance of a pipeline during and after a major seismic event along the fault area.
According to Meier, the material can also be used as a compressible inclusion for systems undergoing static, monotonic and dynamic loadings.
Its controlled compression can be used to reduce earth pressure against buried structures as well as deformation brought on by structural loadings.