Geothermal system at Pa. college uses PVC drop pipe

VALLEY FORGE, Pa. - Nearly 40,000 feet of CertainTeed Corp.'s Certa-Lok drop pipe has been used in the construction of a new geothermal heat system at the U.S. Army War College in Carlisle, Pa.

Some of the 67 wells drilled by Connecticut Wells Inc. of Bethlehem, Conn., contain the polyvinyl chloride, or PVC, drop pipe. The casing functions as a porter shroud to protect the pump and water pipe in each of the wells. The wells range in depth from 350 to 1,000 feet.

The geothermal system, which works by extracting heat from ground water, is replacing a dated central steam system that was beginning to show signs of failure.

"It had become a growing concern for college officials," said project manager Gary Sexton of Co-Energy Group LLC in Las Vegas. "The infrastructure was falling apart. It didn't have much life left."

According to Tom Mahan, owner of Connecticut Wells, Certa-Lok drop pipe is an important piece of the geothermal project and will provide the durability and environmental safety college officials are looking for.

PVC-made Certa-Lok won't rust or rot like metal pipe, according to CertainTeed officials. The drop pipe meets or exceeds all American Society for Testing and Materials standards, the company adds.

Certa-Lok is specified for geothermal wells because it is fast and easy to assemble in all weather conditions and does not require solvent cements to join pipe sections, CertainTeed said.