Since the introduction of cross-linked polythene pipe (PEX) into the residual plumbing market, copper tubing has steadily lost popularity. Both PEX and copper are plumbing choices; however, the 2008 economic crisis compelled potential homeowners, plumbers and building contractors to economise without compromising quality. With regard to materials, both copper and PEX have their advantages and disadvantages; consequently, there are a number of factors to consider before making a final choice.
Escalating copper prices, job site theft, storage, transport and labour costs all affect the price of copper tubing. Despite the added expense of dedicated PEX tools, when a point-by-point comparison is made, using PEX instead of copper represents a cost reduction---without impacting quality, material durability or safety.
PEX is flexible and comes in 100 to 300 m reels. Unlike rigid copper, it does not have to be cut down to manageable lengths. This cuts transport and storage costs. Plus the ability to install long runs incorporating 90-degree bends reduces installation time, because PEX requires fewer elbows and inline connectors. PEX push-fit and clamp-on fittings also do not require solder, corrosive flux or glue. These factors represent a reduction in labour and material costs compared to copper.
Most manufacturers cover PEX tubing and fittings with a 25-year limited warranty. Unlike copper, PEX will not corrode when exposed to low pH water or when buried in acidic soil. In addition, the long-term lime and scale build-up that clogs metal pipe installations is eliminated with the use of PEX; therefore, water flow and pressure will remain constant over the years. However, PEX deteriorates in direct sunlight; it cannot be used outdoors.
PEX plumbing calls for up to 50 per cent fewer joints and right-angle fittings; this reduces the number of potential leaks. Whereas copper piping is prone to rupturing during freezing conditions, PEX resists freezing because its flexibility compensates for the expansion caused by freezing water. This prevents additional cost and inconvenience of burst pipes. On the other hand, copper is also reliable. According to the Copper Development Association, since 1963, seamless copper plumbing tube has been installed in about 80 per cent of all U.S. buildings. The biggest challenge to its durability is the possibility of pinhole leaks. Corrosion of copper piping is rare but can prove costly.
Since copper has thermal conductivity, hot water on its way to the shower or kitchen sink must first heat up the pipes. PEX, on the other hand, does not drain thermal energy easily. This means that when a kitchen or shower faucet is turned on, hot water is delivered much quicker than in a copper based installation. In addition, because PEX tubing is flexible, it helps to absorb sudden surges in water pressure, which can cause a clanking noise in copper pipes.
Copper is known to resist bacteria growth over extended periods. However, because PEX has been used in plumbing installations for a relatively short time, its resistance to bacterial growth is unknown. On the positive side, PEX has been approved for drinking water use, hospital plumbing and in the manufacture of medical equipment, such as kidney dialysis and heart/lung machines. PEX is likely to emit plastic particles over time; however, this also applies to FDA-approved food and beverage containers. Copper, on the other hand, can contribute to health. The National Academy of Sciences Institute of Medicine, Food and Nutrition Board recommends a daily intake of 1 to 3 mg of copper, therefore copper particles leeching into the water supply can contribute to long-term health benefit.