### Technical Memorandum

For: Bay Area Pollution Prevention Group Prepared by: Stephanie Hughes, P.E.
Date: June 25, 2014 Subject: Preliminary Comparison of PEX and Copper for Potable Water Piping

Summary The wastewater community has long been interest ed in upstream pipe materials. In particular, BAPPG and member agencies have been promo ting pollution prevention opportunities in the design and installation of copper piping syst ems since the late 1990s. Meanwhile, both CPVC 1
and PEX 2 have become options in the California plum bing code for potable water. Those actions initiated BAPPG members’ interest in the differe nces between copper and plastic pipe. To date, such reviews have focused primarily on the potential leaching of chemicals from the pipe material. While that is clearly important, I have sought to look at a wider picture, surveying available literature (both peer -reviewed and industry-sponsored publications) to incorporate installation and life cycle aspect s. I have focused on PEX (rather than CPVC) in part because unlike other plastics, it uses brass fittings rather than epoxies, a nd it is being promoted in local hardware stores as a relatively simple do-it-yours elf installation. I have a ssembled my findings in the pages that follow. In summary, my tentative findings are as follows:

1. LIFE CYCLE: When viewed from a life-cycle perspective, PEX appears to have a lower global warming potential compared to copper and may have reduced impacts in other areas as well. 2. WORKER HEALTH: From an installer respiratory perspective, PEX may be preferable to copper pipe. 3. WATER QUALITY: PEX leaches a number of or ganic materials, at least within the initial months following installation. Copper pipe leaches copper for the initial years following installation. Depending on installation pr actices, copper pipe may also leach flux chemicals. Both materials may leach metals from brass fittings and fixtures. 4. MUNICIPAL WATER DISTRI BUTION: Municipalities use PVC and HDPE as materials for drinking water distribution systems, providing some context for a discussion about consumer choice w ith regards to plastic pipes. 5. CONSUMER CHOICE: A consumer’s choice of plumbing material is subjective and there are variety of factors that impact c onsumer decision-making, including health, taste and odor, corrosion resistance, warranty, cost, and convenience of installation. Please review the pages that follow for details on each of these subject areas. BAPPG may want to use this information to conduct additional research and/or update messages with respect to potable plumbing alternatives.

1 CPVC = chlorinated polyvinyl chloride, approved for potable water pipe in California in 2008.
2 PEX = crosslinked polyethylene, approved for potable water pipe in California in 2010.2 Background Copper pipe corrosion has been a major concern to the wastewater community for more than a decade. For many years, the messages have been about proper installation and the use of a waterbased flushable flux (ASTM B813 flux); petrol atum-based, non-ASTM fluxes increase pipe corrosion long after the joint has been soldere d. The BAPPG message is in good standing, as the Universal Plumbing Code (UPC) requires the us e of ASTM B813 flux wh en installing copper pipe.

The reality appears to be that there is a disconnect between standards and plumbing practices. While water-based flux is the standard in the UPC for potable water, the standard appears to be virtually universally ignored. The boots-on-the- ground plumbers and trainers appear to have concerns about the water-based flux, both from a workability perspective and from a health/fume perspective. In addition, of five plumbing stores surveyed in San Francisco, petroleum-based fluxes were the ONLY fluxes available in two stores. 3

These observations led to the conclusion that the va st majority of copper pipe may have been and may continue to be installed with the petrolatum-based flux. This led to questioning whether it is sufficient to provide plumbing messages only about copper pipe, given that at least one key pollution prevention message is ignored. This fu rther led to a consider ation of whether the wastewater community should understand the bi gger environmental picture regarding copper versus plastic pipe. Therefore, this literature se arch has been an initial effort to try to better understand the life cycle, public health, worker safety and environmental impacts of these plumbing alternatives.

Literature Review and Discussion

1. Life Cycle Analyses Life cycle analyses (LCAs) evaluate a material or product throughout the “life” of the material. Such analyses can vary greatly with respect to boundary conditions and the types of impacts that are analyzed. For instance, the analysis might be “cradle-to-factory gat e” (thus, before reaching the ultimate consumer) or “cradle -to-grave” (i.e., include final di sposal). Such analyses might analyze only one metric, such as global warming potential or might evaluate multiple environmental metrics (such as ozone depletion and ecotoxicity). Thus, it is difficult to evaluate and compare life cycle analyses.

Very few LCAs were uncovered for copper and/or PEX pipe materials. Fu rther, typically the LCA was conducted for or by a part icular industry (i.e. copper versus plastic) rather than published in a peer-reviewed application. Neverthele ss, the results are intriguing and valuable to understand. The following papers we re collected and reviewed:

Copper LCA Only
1. European Copper Institute, Brussels, Belgiu m, “The Environmental Profile of Copper Products,” (a summary factsh eet), date not provided ( obtained March 3, 2014 from www.copper-life-cycle.org ).

3 One plumbing store staff person indicated that while they used to sell the water-based product, no one was buying it, so they took it off the shelves.3 PEX LCA Only
2. Carolin, S., Vanderreydt, I, et al., “THIRD PARTY REPORT: Life Cycle Assessment of a PEX Pipe System for hot and Cold Water in the Building,” prepared under the authority of The European Plastic Pipes and Fittings Association, May 2011. Copper and PEX LCAs
3. Franklin Associates, Prairie Village Kansas , “Life Cycle Inventor y of the Production of Plastic and Metal Pipes for Use in Three Pipi ng Applications,” prepared for the Plastic Pipe and Fittings Association, June 2008.
4. Geberit (multinational plumbing part manufact urer and supplier, based in Switzerland) “Life Cycle Assessment: Supply pi pes for buildings,” January 2009
5. Lee, Juneseok, and Easterling, Andrew, San Jo se State University, “Application of the EIO-LCA and LCIA to Premise Plumbing Ma terials,” World Environmental and Water Resources Congress 2012, ASCE.

The results of the five LCAs are summarized in the tables and graphics that follow.

1. “The Environmental Profile of Copper Products,” European Copper Institute, Brussels, Belgium. Materials evaluated Only copper Boundary conditions Cradle-to-factory gate Specific Findings: Global warming potential 900 lb CO 2e / 1000 ft for 0.6 inch diameter pipe

Conclusions “Copper mines are multi-metal mines.” Extraction and processing are primary impacts. Increased recove ry and recycling is important, especially since global copper use is so large. The annual scrap available now equals the production rate of 20-50 years ago.

While this copper-only study did not compare the results to PEX or other materials, it is useful to note that the global warming potential (GWP), as measured in carbon dioxide equivalents (CO 2e ), is within the range of estimates for copper in the LCA Study #3 (below).

Funder Study provided by the European Copper Institute.4 2. Carolin, S., Vanderreydt, I, et al., “THIRD PARTY REPO RT: Life Cycle Assessment of a PEX Pipe System for Hot and Cold Water in the Building,” prepared under the authority of The European Plastic Pipes and Fittings Association, May 2011
Materials evaluated PEX only, including the brass fittings Boundary conditions Included the extrusion, transportation, and disposal of the PEX pipe and brass fittings (assuming 50 years of service). Assumed that 85% of the material was disposed in a landfill while 15% was incinerated with energy recovery. Evaluated abio tic depletion, acidification, eutrophication, global warming, ozone depletion, and photochemical oxidation. Specific Findings: Their “functional unit” for their LCA, rather than a specific length of pipe, was the entire set of piping and fittings needed for a 100 m 2 European apartment. This included multiple lengths and diameters of pipe and numerous associated fittings. Therefore, it would be challenging and time consuming to comp are their calculations with the other studies. That said, below is a su mmary of the major contributors to the environmental impacts. Global warming potential Primary impact is from the production of the raw materials for the PEX pipe. The extrusion of the pipe and the production of the fittings are the next most important life cycle ph ases for global warming potential. Abiotic depletion Primary impact is from the production of the raw materials for the PEX pipe.
Acidification Primary impact is from the production of the raw materials for the PEX pipe and the production of the brass fittings. Eutrophication Primary impact is from the production of the brass fittings. Ozone layer depletion Primary impact is from the production of associated plastic fittings.

Photochemical oxidation Primary impact is from the production of the raw materials for the PEX pipe and associated plastic fittings.
Conclusions End of life stage, which assumed that 85% of the material was disposed in a landfill while 15% was incinerated with energy recovery, was the least impacting life cycle phase fo r all the environmental impacts evaluated.
Funder “Study accomplished under the authority of the European Plastic Pipes and Fittings Association”5 3. “Life Cycle Inventory of the Production of Plastic and Metal Pipes for Use in Three Piping Applications,” Franklin Associat es, Prairie Village Kansas, June 2008.
Materials evaluated Copper, PEX, and CPVC for a 3⁄4 inch pipe for hot and cold water distribution Boundary conditions Raw material extraction through pipe fabrication and transportation from manufacturer to the customer . Includes manufacture and disposal of transportation packaging. Does not include installation, fittings, adhesives, or solder for pipe connections. Specific Findings: Copper PEX Global warming potential Approx. 800-1500 lb CO 2e / 1000 ft of 3/4 inch diameter pipe Approx. 380 lb CO 2e / 1000 ft of 3/4 inch diameter pipe
Solid Waste (included processwastes, fuelrelated wastes,and postconsumer wastes) If zero recycled – NA, this analysis was not included. 4

If 50% recycled, approx. 200-400 lb of waste per 1000 ft of 3/4 inch diameter pipe. If 100% recycled, approx. 50-75 lb of waste per 1000 ft of 3/4 inch diameter pipe. If zero is recycled, approx. 145 lb of waste per 1000 ft of 3/4 inch diameter pipe. If 50% recycled, approx. 80 lb of waste per 1000 ft of 3/4 inch diameter pipe. If 100% recycled, approx. 30 lb of waste per 1000 ft of 3/4 inch diameter pipe.

Conclusions “The use of energy resources as raw materials for plastic resins increased the total energy for plastic pipe systems; however, this is more than offset by the heavier weight of copper pipe a nd the large amounts of energy required to produce the primary and secondary copper.” “Over 75 percent of the global warmi ng potential for all pipe systems is from carbon dioxide from combustion of fossil fuels.”
Funder Prepared for the Plastic Pipe and Fittings Association.

4 Notice the very different assumptions fo r recyclability of copper versus PEX. Copper is a highly valued material and is assumed to be far more likely to be recycled than the PEX material.6 Below are two key tables pasted directly from Study #3. Copper K, L, and M refer to different industry standards for copper pipe, in which the th ickness and weight of va ries, with K being the thickest (and heaviest) per foot and M bein g the thinnest (and lightest) per foot.7 4. “Life Cycle Assessment: Supply Pipes for Buildings,” by Geberit, January 2009
Materials evaluated Copper, PEX, and other supply pipe materials Boundary conditions Mining to disposal (assuming incine ration of PEX and recycling of copper), with a 50 year service life. Specific Findings Copper PEX
Overall EcoIndicator Score (per a Dutch impact assessment method) 5 Approx. 0.6 if 55% recycled Approx. 0.3 if 100% recycled

The primary environmental impacts were mineral extraction and respiratory disease. <0.1

This result was based on the assumption of 100% incineration for energy recovery (European analysis). As to the question of how the analysis would change if final disposal was a landfill, this is answered, in part by Study #2 that assumed 85% of the material was disposed in landfill and yet the disposal was the least impacting stage of the life cycle.

The primary environmental impact was associated with the fossil fuel

resource. Conclusions “From an ecological point of view , pure plastic drinking water pipes (PEX and PB 6 ) have the best results. Plas tic-aluminum multilayer pipes have a slightly higher environmen tal impact due to the additional aluminum layer.” “The higher environmental impact of the copper and stainless steel pipes is due to the weight per meter, whic h is two to three times as high, and because extracting metal from metal ores is extensive and energy intensive”
Funder In-house project by Gerberit, a multinational plumbing part manufacturer and supplier, based in Switzerland.

5 The Eco-Indicator Score incorporat es fossil fuel resources, climate ch ange, acidification, eutrophication, respiratory diseases, fossil fuel combustion, mineral extraction, ozone depletion, land use, and ecotoxicity. The method aggregates all the impacts into a single score. The lower the score, the lower the environmental impact.
6 polybutylene8 Below is a key figure pasted directly from Study #4. This figure was included in Gerberit’s English-language summary. The full report, available in German, provides additional documentation and graphics. The full report also parses out each of these results into the various environmental impacts (i.e., fossil fuel resources, climate change, acidification, eutrophication, respiratory diseases, fossil fuel combustion, mineral extraction, ozone depletion, land use, and ecotoxicity).9 5. Lee, Juneseok, and Easterling, Andrew, Sa n Jose State University, “Application of the EIO-LCA and LCIA to Premise Plum bing Materials,” World Environmental and Water Resources Congress 2012, ASCE.
Materials evaluated Copper, PEX and CPVC Boundary conditions Cradle to gate, not including installa tion, use or end-of-life disposal.
Areas considered Considered human health, ecosystem quality, climate change and resources using a computer model de veloped by Hewlett Packard. Based on a follow-up discussion with the HP model developer, standard model assumptions were used for this analysis, which may or may not have been the most appropriate assumptions for these materials. Specific Findings Given the wide range of impacts evaluated, the figure below best summarizes the results.
Conclusions “The results revealed that for all midpoint and damage impact categories, PEX systems have less of an impact on the environment than either copper or CPVC.” “Results... may be combined with economic, ergonomic, convenience, safety, and other relevant factors to produce a holistic decision model that can be used to optimize material selection.”
Funder Hewlett-Packard and San Jose State University

Below is a key figure pasted from Study #5.10 2. Installer/Worker Safety From a worker safety perspectiv e, soldering of copper includes th e use of solder and soldering flux. Note that the water-flushable flux (the one required for potable water pipe and recommended by BAPPG agencies) has a number oforganic chemicals not included in the nonflushable flux. The ingredients in two typical fluxes on the market are presented below, along with a couple of findings about possible health co ncerns. In addition, I ha ve received anecdotal complaints from Bay Area plumbers regarding the water flushable fl ux, contending that the fumes are more noxious than petrolatum-based flux.

Topic Copper PEX Products used during installation  Water flushable (ASTM B813) flux 7

 Solder  Non-flushable (petrolatum based) flux 8

 Solder PEX pipes are connected with brass fittings.

Ingredients  Flux:

o Ammonium chloride

o Ethanolamine hydrochloride

o Paraffic oil

o Petroleum derivatives

o Polyethylenepolypropylene glycol

o Glycerine

o Polyethylene glycol octylphenyl ether

 Lead-free solder

o Tin

o Silver

o Possibly antimony  Flux:

o Ammonium chloride

o Petrolatum

o Zinc chloride

 Lead-free solder

o Tin

o Silver

o Possibly antimony Not applicable

Possible respiratory

concerns  Occupational asthma from ammonium chloride and zinc chloride 9

 "A qualitative assessment of organic vapors released during... soldering of copper plumbing systems. The organic vapors from three soldering paste fluxes and a solder paste flux...included a series of alipha tic hydrocarbons, aromatic and polyaromatic hydrocarbons, chlorinated benzenes, oxygenated aromatic materials, and se veral chlorinated phenols." 10

 Neither study evaluated the po ssible long-term exposure of heavy metals from the solder. Not applicable

7 Nokorode Aqua Flux MSDS
8 Nokorode Regular Paste Flux MSDS (a common flux found in local plumbing supply shops)
9 Weir, DC, Robertson, AS, Jones, S., Burge, PS, “Occupational Asthma due to Soft Corrosive Soldering Fluxes Containing Zinc Chloride and Ammonium Chloride,” Thorax, Vol. 44, No 3, 1989. (Reviewed abstract only.)
10 Nikora, JA, Olson, AJ, and Steele, WC, “Identification of Organic Vapors from Commercially Available Soldering Fluxes During Simulated Soldering of Copper Plumbing Systems,” American Industrial Hygiene Association Journal, Vol 51, No. 7, pages A476-A477, 1990. (Reviewed abstract only.)11 3. Water Quality / Leachants I have previously conducted prior reviews of leaching from plasti c pipes, including discussions of aquatic toxicity and human health concerns. 11 Below is a brief summ ary of likely leachants from copper, PEX, and CPVC.
Leachant Copper PEX CPVC Chemicals that may leach from the pipe material

NOTE: Copper and PEX include brass fittings and fixtures which leach
copper, led, nickel and zinc. 12 Copper Flux residual (see section immediately above) A number of volatile organic compounds may leach from PEX. For instance, in one study the following were the primary leachants: 13

 Methyl tert-butyl ether (MTBE)

 Tertiary butanol

 4-Butoxy phenol

 5-Methyl-2-hexanone

In that study, there were additional VOCs that were measured and there were unidentified VOCs that were not quantified.

In another study, the following were the primary leachants: 14

 MTBE

 2,4-di-tert-butyl phenol A number of volatile organic compounds may leach from CPVC. The following organotins appear to be of most concern from a health standpoint:

 Monobutyltin

 Dibutyltin

 Tributyltin

A review by the AWWA Research Foundation suggested that a number of additional chemicals could leach from PVC/CPVC water systems. 15 Some VOCs may be attributed to the cement solvents. Because CPVC formulations have changed over time, it is unclear whether these VOCs would be measured leaching from currently available CPVC pipe and associated solvents. Timescale of chemical leaching Copper will corrode most significantly in first years following installation (prior to a protective patina coating). It will continue to corrode at sites of turbulence, flux residual, or due to water chemistry or other physical/ chemical factors. In both studies referenced above, the concentration of MTBE was originally greater than the US EPA MCL (maximum contaminant level) but decreased with time. In the 2011 study, the MTBE concentration decreased below this value in 5 months. That study concluded that the overall potential health concern was low, but that the odor could negatively affect drinking water for up to one year. Based on available evidence, it appears that organotins are released from CPVC pipe and may do so for a number of days under typical use conditions. It is unclear the length of time over which this leaching would continue in a residential setting. 16

11 Hughes, Stephanie, “CPVC for Potable Water Piping: Review of Chem ical Leaching Data and Related Toxicity Information” technical memorandum to the PARWQCP, September 2008.
12 Kimbrough, David, “Source Identification of Copper, Lead, Nickel and Zinc Loading in Wastewater Reclamation Plant Influents From Corrosion of Brass in Plumbing Fixtures,” Environmental Pollution, Vol 157, 2009. 13 Skjevrak, I., et al, Volatile Organic Compounds Migra ting from Plastic Pipes (HDPE, PEX, and PVC) Into Drinking Water, Water Research (2003) 1912-1920.
14 Lund, V, et al., “Long Term Study of Migration of Volatile Organic Comp ounds from Cross-linked Polyethylene (PEX) Pipes and Effects on Drinking Water Quality,” Journal of Water and Health, Volume 9, 2011.
15 Tomboulian, P., Schweitzer, L., Mullin, K., Wilson, J., & Khiari, D. (2004). Materials used in drinking water distribution systems: contribution to taste and odor. Water Science and Technology , 219-226.
16 Hughes, Stephanie, “CPVC for Potable Water Piping: Review of Chem ical Leaching Data and Related Toxicity Information” technical memorandum to the PARWQCP, September 2008.12 4. Municipal Water Supply Material Choices According to California regulations, PVC and HD PE are among the materials that may be used for drinking water mains. The table below was pasted from “California Regulations Related to Drinking Water” as of July 1, 2103

. 17 While PEX is not on the li st, the use of other plastics throughout water distribution system s does provide a context with which to consider consumer pipe choices.

5. Consumer Choice Dr. Juneseok Lee, a professor at San Jose Stat e University (and author of Study #5) has been reviewing consumer decision making with regard to plumbing materials. He has estimated that in the USA, about 90% of home plumbing system s are copper pipe, and that pinhole leaks have become a concern due to property damage, property values, and insurance concerns. 18 He studies consumer preferences and decisions , and in particular has conducte d surveys in a region prone to pinhole leaks in copper pipe. While surveyed home owners indicated that health, taste, and odor were dominant considerations, they sometimes stat ed preferences to a survey that differed from their real-life choices. On the following page are a table and two pie charts pasted from Dr. Lee’s research, summarizing parameters that impact consumer choice and the plumbing selections made by households that replumbed their homes. 19 Dr. Lee concluded that “ the choice of plumbing materials is inevitably subjective and, in real life, numerous factors influence the selection of a particular pipe material .”

17 Available from www.cdph. ca .gov

. 18 Lee, et al., “Case Study: Preference Trade-Offs Towa rd Home Plumbing Attributes and Materials,” Journal of Water Resources Planning and Management, ASCE, July/August 2009.
19 Lee et al., “Homeowners’ decisi on-making in a premise plumbing failure prone area,” Journal AWWA, Vol 105:5, May 2013.13 The following figures are directly from: Lee et al., “Homeowners’ decision-making in a premise plumbing failure prone area,” Journal AWWA, Vol 105:5, May 2013 . NOTE: the surveyed community was in a region that wa s prone to pinhole leak s in copper pipe.

Endnotes This concludes the summary of my initial findin gs. BAPPG may want to use this information to conduct follow-up analysis and/or to update messages with respect to potable plumbing alternatives. I intend to summarize this in formation at the August 2014 BAPPG meeting to initiate a discussion about next steps, if any.