Builders Websource Tech Note #060201-1

CPVC vs. COPPER PLUMBING:

Mysteries Unraveled

Last Update 06.30.12

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When building or purchasing a home, consumers ask whether CPVC piping or traditional copper plumbing is best for hot and cold potable water supply. This Builders Websource Tech Note explores the benefits and considerations of both CPVC and copper plumbing for domestic water supply use. Applications, environmental considerations, lifecycle costs, limitations and health effects are examined. Results from over 100 pages of research are condensed into this handy authoritative guide for professionals and consumers alike.

Table of Contents

• Abstract
• Introduction to CPVC and Copper Plumbing
• Benefits and Considerations of CPVC
• Health Effects of CPVC
• Specifying CPVC Pipe
• Benefits and Considerations of Copper
• Health Effects of Copper Plumbing
• Cost Comparison: CPVC and Copper Tubing
• Application of Copper Pipe (TABLE)
• Working Pressure of Copper Pipe (TABLE)
• Conclusion
• Copyright Notice

Introduction to CPVC and Copper Plumbing

Over the years, a range of materials have been used to deliver potable water for industrial and residential uses. Early on, galvanized steel pipe was used for water distribution. This suffered from high cost of installation and internal corrosion, which after 30-40 years of use eventually constricts the water flow to the point of being ineffective.

For several decades now, copper tubing has been the mainstay and preferred method of water distribution inside residential structures, accounting for approximately 85% market share in new construction. When installed properly and when the water supply is non-acidic, copper plumbing has proven the test of time as a reliable and safe delivery vehicle for potable water.

However, in recent years, new materials have entered the market to challenge copper's dominance. PB, or Polybutylene tubing was popular for its low cost of installation compared to copper. However, excessive failures in the field led to class action lawsuits and the ultimate banning of PB in 1995. Over the years, a better substitute has emerged called CPVC, or chlorinated polyvinyl chloride. B.F. Goodrich (now called just "Goodrich") holds multiple patents on the resins, which it licenses to pipe manufacturers under the name FlowGuard Gold®. (As of June 2001, FlowGuard Gold® is now marketed under the Noveon name). CPVC is typically beige or light grey in color and is now approved by virtually every model building code for use in residential water distribution systems.

Compared to copper, CPVC appeals to some homebuilders due to its lightweight nature, ease of installation and lower overall installed cost. Often, these savings can be passed on to the consumer in terms of overall lower prices for homes.

However, as with any new material that challenges the proven performance of its predecessors, CPVC is not without its critics. Many professional plumbers avoid installing CPVC for fear of callbacks or lawsuits. With the PB scare still in recent memory, many do not understand the pros and cons of CPVC vs. copper plumbing, and therefore stay away for fear of the unknown.

This Tech Note is designed to demystify CPVC and help to educate consumers and professional under what conditions CPVC should be used, while pointing out the important considerations of both materials.

Benefits and Considerations of CPVC Plumbing

• Resistance to corrosion and abrasion
• Smooth bore for improved flow and reduces water noise
• High impact strength
• Easy, cost-effective installation
• Competitively priced vs. copper
• Lightweight reduces heavy lifting
• Less subject to jobsite theft
• Self-insulating to minimize thermal loss
• Integral flame retardancy and low smoke density
• Pressure rating of 100 PSI @ 180° F, 400 PSI at 73° F
• Short-term pressure rating > 200 PSI
• Flexibility virtually eliminates water hammer (no water hammer arrestors required under normal conditions)
• Inert to acidic soils and corrosive water supplies
• Can be buried directly under slabs with no chemical interaction with concrete
• Non-conductive
• Eliminates pressure leaks at solder joints
• Easy for DIY'ers
• Virtually no sweating or condensation
• Relative price stability over time

Considerations of CPVC pipe include:

• Generally limited to 1/2" to 2" Copper Pipe Size
• Some complaints of "plastic taste" in water
• Fittings and pipe subject to cracking or damage on job site if dropped or stepped on
• Solvents used to join fittings and pipe contain volatile organic compounds (VOCs) which are known pollutants and require proper ventilation during installation
• Subject to melting during a fire (becomes viscous at 395° F)
• High coefficient of expansivity (1 inch in 50 feet over 50-degree temperature change) (3.4x10^-5 in/in/°F)
• Inner CPVC pipe surface can support the growth of bacteria including legionellae pneumophilia (ref. A Comparison of the Colonization by Bacteria of Copper and Other Materials Commonly Used in Plumbing Systems with Special Reference to Legionella Pneumophila)
• Due to ease of installation, CPVC is sometimes installed by less skilled labor, potentially resulting in more frequent incidence of improper workmanship.
• Subject to cracking during earthquakes
• Generally requires a 24-hour cure period before pressurizing with water
  

Standards and code compliance (eg. FlowGuard Gold®)

• Meets or exceeds ANSI/NSF Standard 61 for potable water
• Meets of exceeds all ASTM and industry standards
• Meets model building codes, BOCA National Plumbing Code, National Standard Plumbing Code, Standard Plumbing Code, Uniform Plumbing Code, CABO 1- and 2-Family Dwelling Code, Canadian Plumbing Code

Health Effects of CPVC

VCM is made by heating ethylene dichlroride (EDC) to 700 degrees F in the presence of oxygen. VCM is used to produce PVC resins which are used to make pipe and other materials using a process known as polymerization. During this process, most, but not all of the VCM is consumed. Trace amounts remain trapped in the PVC resin where it either outgasses into the atmosphere, or migrates into food or drink stored in containers or pipes made of PVC. This remaining chemical is residual vinyl chloride monomer, or RVCM.

For the record, all national building codes have approved CPVC for potable water distribution in the United States and Canada. These approvals have come after extensive testing and quality control standards which guide the production of these products. Today's product meets stringent ANSI/NSF-61 standards for water quality control. There is no scientific evidence that CPVC tubing made to current US standards is in any way harmful to health.

However, there is little argument that extended exposure to VCMs which exceed government standards, can lead to neurological and liver effects as well as cancer, such as angiosarcoma - a normally rare form of liver cancer. As long ago as 1961, Dow Chemical researchers concluded that exposure to Vinyl Chloride levels greater than 50 ppm were considered potentially dangerous.

Generally, high exposure levels of VCM have been historically limited to workers who produced CPVC and PVC products on a daily basis. In some cases, there have been increased incidences of rare illnesses clustered in areas near manufacturing facilities using vinyl chlorides. The shroud of secrecy surrounding VCM broke when, on January 23, 1974, B.F. Goodrich responsibly reported that it had traced three fatal cases of angiosarcoma among workers at its Louisville, Kentucky plant.

In a 1998 Houston Chronicle article by Jim Morris called "Toxic Secrecy," the ill effects of long-term exposure to VCM is well documented. Furthermore, the US Environmental Protection Agency (EPA) produced a revised fact sheet on January 27, 1998 on Vinyl Chloride as part of the National Primary Drinking Water Regulations.

The EPA report, which is intended to be an unbiased information source, states that "vinyl chloride [can] potentially cause neurological effects from acute exposure at levels of 0.002 mg/L."

"Drinking water levels with are considered 'safe' for short-term exposures: For a 1--kg (22 lb.) child consuming 1 liter of water per day: a one- to ten-day exposure of 3 mg/L; upto a 7-year exposure to 0.01 mg/L."

"Major human exposure will be from inhalation of occupational atmospheres and from ingestion of contaminated food and drinking water which has come into contact with polyvinyl chloride packaging materials or pipe which has not been treated adequately to remove residual monomer."

Granular activated charcoal and packed towared aeration are considered the best technologies available for treatment of water containing RVCM. 

Other findings reveal that extended exposure to VCM has been linked to a hand disability called acroosterolysis, although this has been generally limited to people who routinely cleaned production reactors. It should be noted, however, that according to ASTM Standard F402-88--and underscored by the Plastic Pipes and Fittings Association (PPFA) User Bulletin 8-82--gloves should be worn when handling CPVC pipe, although many installers fail to follow these guidelines or are unaware of them.

In addition, an unusual level of brain cancer was reported between 1951 and 1977, including astrocytoma and glioblastoma, at one manfacturer, although the manufacturer denies any conclusive linking.

Today, the production of CPVC pipe is strictly regulated. NSF (National Sanitation Foundation), a public non-profit organization dedicated to public health and safety, audits many manufacturers of plastic pipe including CPVC, PVC, acrylonitrile-butadiene-styrene (ABS), polyethylene (PE), and cross-linked polyethylene (PEX).

Products with the NSF certification are tested in accordance with NSF Standard 61. PVC and CPVC pipe is tested twice annually for RVCM, ensuring that production samples remain below established maximum allowable levels. Products with the NSF-pw certification are further tested for compliance with all other properties, including health-related.

Therefore, if CPVC is contemplated for use in any structure for a potable water supply, it is critical that the product is NSF certified. Most codes make this a requirement, but it is no guarantee that the contractor has followed these guidelines when purchasing materials. Imported products from other regions outside the US may not meet these guidelines and could pose a health risk over time.

Specifying CPVC Pipe (example)

Benefits and Considerations of Copper Plumbing

• Proven, long-term durability in non-acidic installations
• Biostatic - does not support bacteria growth
• Very diverse material. Can be used for potable water supply, drain/waste/vent (DWV), natural gas supply, high-pressure steam and other applications
• Earthquake tolerate
• Very fire resistant; high melt point (1981°F) is 5-times higher than CPVC
• Widely accepted by all building codes
• Contemporary US-Made copper pipe is 99.9% pure according to ASTM specifications (note that older copper pipe may contain higher amounts of lead).
• High rated internal working pressure (see Table)
• Ready for use with minimal delay
• Can be bent to avoid obstructions, minimizing joints
• Available in annealed (soft) and drawn (hard) versions for ultimate installation flexibility
• Small external diameter relative to CPVC - fits in tight places
• Joints are not bulky
• Long warranties available (up to 50 years)
• Preferred by most homeowners - can increase resale value of home
• Can be pressure tested in 10 minutes

Considerations of copper pipe:

• Some report of "metallic taste" to water
• Can produce "pin hole" leaks in presence of acidic water
• Limited in some areas to use only when water pH is less than 6.5 - 6.8 (acidic)
• Can leach lead or copper into water supply
• Suitable for use when pH is between 6.5 and 8.5
• Subject to jobsite theft
• Labor intensive installation process requires skilled plumber
• Calcium build-up can occur, constricting water flow
• Higher initial installed cost (labor and materials)
• Thermal loss - requires insulating jacket
• Condensation can occur if not properly insulated
• Noisy at high water velocities
• Subject to water hammer at velocities higher than 5 FPS; may require water hammer arrestors to mitigate damage
• Copper joints prone to failure at high temperatures (180°F and velocities)
• Installation with gas torch is a potential fire hazard
• Repairs difficult for DIY'ers, requiring special training and tools
• Cannot make solder repairs with water in pipes
• Price of copper fluctuates over time depending on raw materials demand

Health Effects of Copper Pipe

According to Fine Homebuilding Magazine, "although copper is resistant to corrosion, there are conditions that copper tubing doesn't like. They include hard well water; soft, acidic water; excessive water velocity or turbulence in the line; too much flux during installation; and what the Copper Development Association calls "aggressive soil conditions." Those who have had trouble with thinner-walled tubing may switch to type L or type K for longer service life."

Copper proponents point out that this is not a "pipe" problem, but a water pH problem and that the source of the aggressive water should be rectified. However, this is not always practical, particularly with in many rural areas where wells are common. In severe situations, pH neutralizers are available which can treat incoming water to provide more benign conditions to copper pipe.

Acid neutralizers for a single family dwelling are available for less than $500 and can treat incoming water with pH of 5.5-6.9, depending on model. Anything under a pH of 7 is considered acidic and should be treated. Calcite and Corosex are used to raise the pH of the water. Generally, a whole house sediment filter is recommend to be placed after treatment to remove unwanted contaminants.

With respect to possible lead poisoning, much has been written about the harmful effects lead can have, particularly on young children whose brains are in a state of rapid development. Lead has been linked to learning disabilities and other side effects which are irreversible. If you suspect that your drinking water contains lead, have it tested by a certified laboratory. Testing of so called "first water", which is what comes out of the tap initially is compared to water which has been flowing for several minutes. Levels of lead are determined. Often, simply by running water for 20 seconds prior to drinking it is a good safety precaution if your pipes contain lead solder. Brass fixtures, particularly those made before 1987, may contain high levels of lead than permitted by current standards.

The Safe Drinking Water Act (SDWA) requires that after June 19, 1986 only "lead free" pipe, solder or flux may be used in the installation or repair of (1) Public Water Systems, or (2) any plumbing in residential or non-residential facility providing water for human consumption, which is connected to a Public Water System. Under section 1417(d), "lead free" as defined in the SDWA means that solders and flux may not contain more than 0.2 percent lead, and pipes, pipe fittings, and well pumps may not contain more than 8.0 percent lead.

Cast fittings are made from Copper Alloy C84400 which consists of 81% Copper, 7% Lead, 3% Tin and 9% Zinc per ASTM Specification B584. Wrot Copper fittings are made from commercially pure copper mill products per ASTM Specifications B75 Allow C12200.

Today, copper pipe made in the US generally conforms to very high levels of purity with virtually no lead or other minerals. The final product is called phosphorus-deoxidized, high residual phosphorus copper. It bears the designation C12200 under the Unified Numbering System (UNS) used to identify metals and alloys. This copper is 99.9%+ copper (Cu),  and is of essentially the same purity as fire-refined copper produced from ore. It is produced to the specifications of ASTM B88.

Studies sponsored by the International Copper Association indicate that copper contains certain beneficial characteristics with respect to bacteria growth. Copper is biostatic and does not readily support the growth of bacteria. As a result, copper may offer certain advantages in reduced formation of biofilms and bacteria growth within the pipe.

Materials Cost Comparison of CPVC to Copper Tubing

As of the time of writing, the following table compares the US list price of CPVC CTS (copper tubing size) to traditional copper tubing. Prices will fluctuate but this give a relative indicator of the price differential between raw materials from two different manufacturers. In smaller sizes (1/2"-3/4") commonly found in residential applications, CPVC is 20-30% cheaper. In larger sizes (1"-2"), copper pipe is 10-18% cheaper. This analysis does not take into account cost of couplings or labor required to install either product. This table merely highlights that CPVC and copper are priced competitively with each other. Labor costs would typically swamp the differential in materials cost between CPVC and copper.

Application of Copper Pipe

Source: Cambridge-Lee Industries, Inc.

Working Pressure of Copper Tube

Source: Cambridge-Lee Industries, Inc.

Conclusion

Copyright

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