Wednesday, May 6, 2009

PVC AND OTHER PIPING...ADVANTAGES AND DISADVANTAGES

In my continuing and hopefully final discussion of supply piping materials, today let’s talk about the other major forms of materials used. In previous day's blogs I talked about the use of copper, most consider it to be the premium material and it certainly is the most expensive, then there is PEX, the new kid on the block who’s advantages outweigh it’s disadvantages by a considerable margin. PEX is still relatively new and unfamiliar to most of us. There is considerable controversy both code wise and in connection problems with PEX.
Other primary alternatives are galvanized steel, brass and the PVC (polyvinyl chloride) family. Like copper, steel and brass are very expensive and have similar advantages and disadvantages. Both copper and brass must be soldered in the connections and can represent a fire hazard during the installation phase but it’s rare. Both have the potential to build up scale over years of use which can eventually impede the water flow and copper can eventually develop pinhole leaks caused by electrolysis. These problems, mostly the expense, caused the development and wide spread use of PVC for both supply and drain lines in homes. PVC is inexpensive, easily connected by utilizing PVC glue and a whole family of connectors and is easily installed, like an erector set, making it friendly to most of us DIYers. These days some codes have outlawed plain PVC for supply lines and now require CPVC (chlorinated polyvinyl chloride) which is considered safer and less likely to impart any chemical taste or hazard especially in hot water lines.
The general disadvantages of PVC or CPVC are that it is highly susceptible to ultraviolet light degradation thus should be used, primarily, in internal uses, it is more susceptible to freezing and must be highly insulated in very cold climates and is a very poor insulator for heat and cold so there can be considerable loss of energy especially in hot water lines. PVC can also be noisy especially when used for drain lines, an almost impossible problem to avoid without considerable sound deadening efforts. PVC supply lines can, like metal lines, also flex and pop causing some of the noise commonly thought of as water hammer, but water hammer, as I discussed in a previous blog, is not just solely caused by the material but by air trapped in the lines. Metallic and plastic lines, except PEX, are too inflexible to offset this action. The last home I had with PVC lines was trouble enough to cause me to never want to use it again. You could hear water draining down the piping every time a toilet was flushed or a faucet was turned on. Despite considerable efforts to insulate the piping every severe winter we experienced frozen and ruptured pipes somewhere in the house and generally the installation looked and sounded cheap. Why? Because it was.
I’m sure that there are more disadvantages and advantages that I have missed, each based on all of the individual experiences of each of us. Hopefully I have hit the high spots and I welcome and ask that you share any and all of your own personal experiences, with any of these materials, in the comments segment of this blog.

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