by Janet Arden
Homebuilding and residential and commercial renovations continue to drive a large segment of the U.S. economy, with renovations to kitchens and bathrooms representing a considerable share of this marketplace. Plastic piping systems for water service delivery and drain, waste, and vent (DWV) installations can mean the difference between an affordable renovation project and a fiscally impossible one. However, when it comes to replacing antiquated systems, the role of plastic products is not limited to houses and smaller commercial buildings.
Design/construction professionals, homeowners, and building managers are increasingly turning to plastic pipe for extensive plumbing renovations. As the following three case studies illustrate, plastic products’ ease of installation—which also dramatically cuts costs—and their reputations for long service make these modern plastic materials a convincing choice.
New PEX piping, vintage home
When an experienced remodeler acquired an 1813 townhouse along Philadelphia’s Society Hill, he knew he had to accommodate the heating/plumbing needs of prospective buyers whom he hoped would pay a seven-figure price for the prime property. The chosen material would have to support the latest modern amenities and work with the aesthetics of an early 19th Century structure. As such, he selected flexible cross-linked polyethylene (PEX) plastic piping for both heating and plumbing assemblies. Labeled products made from this thermoset material meet the requirements of ASTM International F 876, Standard Specification for PEX Tubing, and ASTM F 877, Standard Specification for PEX Plastic Hot- and Cold-Water Distribution Systems. Recognized by most model plumbing codes, this polyethylene (PEX) plastic tubing can be used in potable water distribution systems provided it:
has been tested in accordance with the governing standard; meets the requirements of American National Standards Institute (ANSI)/NSF International 61, Drinking water system components— Health Effects; and bears proper certification from a recognized testing agency.
Polyethylene (PEX) plastic tubing is also widely employed for heat-transfer applications, not only for low-temperature uses (e.g. radiant floor heating, snow melting, and ice rinks), but also for distribution piping reaching temperatures up to 93 C (200 F), such as in hot water baseboard, convector, and radiator projects.1
In Society Hill’s case, the polyethylene (PEX) plastic hydronic system circulates heated water through flexible plastic tubes installed under the floor. This heat is then transferred from the floor up without the inefficiencies of forced air. (Forgoing forced air can also allow for the elimination of needless drafts in an old, high-ceilinged structure.)
The same flexible polyethylene (PEX) plastic piping delivered water to the kitchen and baths from an efficient manifold system. Each fixture has its own continuous distribution line, with a reservoir in the manifold allowing several fixtures to be used simultaneously without significant pressure loss. The flexible polyethylene (PEX) plastic tubing easily runs through stud walls and around obstacles—its use eliminated multiple joints and soldered connections, a benefit that provides possible savings on up-front installation costs and lowers the potential for future leaks.
Chlorinated polyvinyl chloride (CPVC) is a thermoplastic pipe and fitting material used for potable water distribution, corrosive fluid handling, and fire suppression. It meets the requirements of ASTM Class 23447, as defined in ASTM D 1784, Standard Specification for Rigid PVC Compounds and CPVC Compounds.
Since Chlorinated polyvinyl chloride (CPVC) materials do not support combustion, they cannot burn without an external fuel source. This property makes them an attractive pipe alternative for fire sprinkler applications, which are approved for light hazard applications and for use in single and multi-family dwellings. (Installation must be in accordance with the National Fire Protection Association [NFPA] Section 13, 13D, and 13R.) Chlorinated polyvinyl chloride (CPVC) fire-sprinkler pipe must be tested and listed in accordance with Underwriters Laboratories Inc. (UL) 1887, Fire Test of Plastic Sprinkler Pipe for Flame and Smoke Characteristics.
While Chlorinated polyvinyl chloride (CPVC) plumbing pipe can be considered safe within return air plenums (provided it meets NFPA 90-A, Installation of Air Conditioning and Ventilating Systems), its installation must be approved by the local jurisdiction. However, Chlorinated polyvinyl chloride (CPVC) piping for potable hot- and coldwater distribution systems is recognized in all model plumbing codes.
More floors, more units, more plastic piping
Home to upscale residential condominiums and numerous law offices, the 25-story Westgate Tower is a landmark on Austin, Texas’ skyline. Although the building’s history dates back only to the 1960s, it was experiencing a number of costly and potentially damaging leaks from its existing plumbing pipes, made of traditional materials. (The contractor hired to resolve the issue said new leaks were springing on almost a weekly basis.)
In 2000, the owners association decided to re-pipe the entire building. The initial bids were very high—up to $2.5 million—and included proposals for removing the old pipes and installing replacements in the same locations. However, the original piping was insulated with asbestos, laying the groundwork for an additional, expensive abatement project. The company that eventually landed the job, Austin-based HHCC Inc., chose to leave the old piping and its asbestos insulation in place and install a new Chlorinated polyvinyl chloride (CPVC) piping system. These pipes and fittings were then installed down stairwells and in main corridors, hidden behind a new, decorative crown molding.
One of the primary reasons for choosing Chlorinated polyvinyl chloride (CPVC) was the near elimination of failure caused by the area’s aggressive water—a problem that can be suffered by pipes made of more traditional materials. The corrosion was extensive on the building’s old pipes and, given the structure’s size, the risk of major flooding was considerable.
HHCC estimates the switch to Chlorinated polyvinyl chloride (CPVC) saved at least 50 percent of the installation time and more than $1 million in project costs (most of it in labor). The material was installed faster than its traditional counterparts and was easily fabricated as required on-site. In addition to replacing the piping, the contractor also had to perform extensive patching and repainting. However, all renovations were completed in a six- to sevenmonth time frame without extended disruptions to most tenants.
Since the Chlorinated polyvinyl chloride (CPVC) chosen for the job required a one-step solvent cement process for connections and fittings, soldering was not an issue. HHCC says the cementing process was cleaner, faster, and eliminated the fire risk associated with other methods. The firm also found Chlorinated polyvinyl chloride (CPVC) to offer superior noise and condensation performance. Although acoustics is always an issue in high-rise buildings, the flexible plastic building product used in this project was considered quieter than its rigid counterparts.
1 For more on PEX in heating applications, see “Warming Up to PEX Pipe Radiant Heating Systems,” by Camille Rubeiz, PE, and Michael Ball in the May 2004 issue of Modern Materials. Additional information on the plastic’s use in plumbing can be found in “Flexing Your PEX: Plumbing the Possibilities of Cross-linked Polyethylene Pipes,” by Camille Rubeiz in the November 2004 issue of Modern Materials.
Janet Arden is the publications editor for the Plastic Pipe and Fittings Association (PPFA), a national trade organization comprising manufacturers of plastic piping, fittings, and solvent cements. She can be contacted via e-mail at email@example.com.