Since ancient times, people have used pipes to transport water from source to point of use. The pipes have been made of many materials, including stone, concrete, wood, metal (lead, iron, copper) and, most recently, plastic.
Plastic pipes made of rigid polyvinyl chloride (PVC) are now widely used to carry drinking water and waste water in homes and other buildings, and sometimes outside of buildings, because they have many practical advantages. For example, they are derived from abundant petrochemicals and sodium chloride salt; their characteristics can be modified by the addition of various chemicals; they are light weight, non-corroding, chemically-resistant, non-conducting, easy to cut and join, and cost-less to transport and handle than other types of pipes; and they seem to be long-lasting compared with pipes made with other commonly-used materials.
Considering the whole life cycle of PVC plastic pipes, however, there are many disadvantages in using them. For example, they require large amounts of energy to make; the source materials and intermediate products, including chlorine gas, are toxic; some chemical additives used in the manufacturing process are harmful and have the potential to leach into drinking water; the additives make recycling nearly impossible, with the result that nearly all discarded PVC goes to landfills; incineration creates dioxin; and high temperature and exposure to sunlight can result in degradation.
Recently, various forms of flexible polyethylene (PE), high density polyethylene (HDPE), and cross-linked polyethylene (PEX) pipe have been used to carry water in buildings because they can be used in confined areas and can be curved to change direction rather than cut and joined. It has been found, however, that they cause odor problems and can release regulated and unregulated contaminants into the water.
For these reasons, EPA is seeking innovative materials that can be used to make drinking water and waste water pipes for buildings and perhaps outside that have the advantages of PVC and PE, HDPE, and PEX pipes without their disadvantages across their entire lifecycle.
Topic Code 1C: Replacements for PVC and PE Water Pipes. Innovative pipes for drinking water and waste water in buildings and perhaps outside of buildings that are made from materials that have the advantages and not the disadvantages of currently-used plastic pipes.