Serving as the main patient-care facility on the 17-building, state-run Southwestern Virginia Mental Health Institute (SWVMHI) campus in Marion, Va., the 102,000-sq-ft Bagley Building was experiencing premature chronic failures of its plumbing system.
According to Don Chisler, SWVMHI's director of physical-plant services, safety, and security, the piping, which was less than 10 years old, was made of Type K copper. What started as three or four leaks a year soon grew to 25 to 30.
To identify the problem, Chisler's team removed a section of pipe. Once the insulation was removed, speckled green corrosion could be seen all over the surface of the pipe. When scraped with a pocketknife, the corrosion popped off to reveal small pinholes. Clearly, the pipe was being eaten through from the inside.
Water-chemistry experts from Spectrum Design PC concluded that aggressive water was a factor in the advanced corrosion.
Hospitals are required to continuously recirculate lines to provide hot water on demand. That, combined with aggressive water and on-site softening of water, created a situation unsuitable for copper piping.
Following Spectrum's recommendation, SWVMHI repiped the facility with chlorinated-polyvinyl-chloride (CPVC) piping.
Reinstalling copper piping would have involved extensive use of torches, which generate smoke and, thus, may have necessitated the facility's fire-detection system being shut down to avoid false alarms, which would have put patients at risk. No torches are needed to install a CPVC system. The only time a life-safety system has to be shut down during a CPVC-repipe project is when the old pipe is cut out.
Because of its high limiting-oxygen index, CPVC will not burn unless a flame is applied; burning stops once the ignition source is removed.
Legionella bacteria can collect in pitted areas of metallic pipe. CPVC pipe prevents Legionella bacteria from collecting — in part because of its smooth inner walls.
A 1999 study commissioned by the Netherlands Ministry of Housing, Spatial Planning and the Environment and conducted by KWR, a Dutch institute dedicated to water-cycle research, found that the growth of Legionella bacteria was much lower in the presence of CPVC materials than it was in the presence of copper and other plastics.
CPVC plumbing systems do not pit, scale, or corrode in aggressive-water and soil conditions.
Waters known to be corrosive to copper piping include hard well waters, which cause pitting, and soft, acidic waters (pH less than 7.0), which do not allow a protective film to form inside. Additionally, certain soil chemistries or compositions are damaging to copper piping, which can develop pinholes and leaks in just a few years.
Copper-tube-size CPVC piping systems utilize a one-step solvent-cement joining system that can be pressure-tested in as little as 10 min. Unlike copper, CPVC is relatively light in weight and does not require special equipment. Additionally, a branch line or other piping modification can be made easily during nearly any stage of the construction process. Lastly, if damaged, CPVC can be repaired quickly.
At SWVMHI, patients were moved from their normal ward to a vacant ward, where the repipe was completed, for only two weeks. If copper piping had been reinstalled, the project could have taken twice as long.
In addition to labor and material, CPVC saves money on heating and cooling, reducing condensation and “sweaty pipes” in conditioned buildings. Less energy is lost through the wall of CPVC pipes than copper pipes.
Information and photograph courtesy of Lubrizol Advanced Materials Inc.
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