Over that time we have discovered many myths about plastic pipe suitability and durability that we can put to rest here. A common thread in our experience is that many industrial users of pipework consider all plastic pipe installations to be the same. However there are several types of plastic pipe used and available commercially and each is designed for specific applications.
It is a fact that generally fittings such as valves, elbows, tee joints and so on can cost more at the purchase stage when compared with steel. The savings come from time saved in installation, the quick jointing process and light weight have a huge impact on labour costs and time on site. Many times we have found that plastic pipe installations can reduce overall contract costs by as much as 50%.
On the contrary plastic pipe installations, in our experience, have always caused less issues than their steel or copper counterparts. Metal pipe systems can suffer from corrosion, particularly with aggressive fluids, shortening life span and usually needing more maintenance to keep them working efficiently. Regular flushing and checking can be the norm more particularly in sensitive water systems where contamination may not be acceptable. Plastic pipe systems, by there nature, are non corrosive eliminating any long term maintenance cost issues. Limescale build up in water systems are virtually eliminated due to the smooth bore associated with all types of plastic pipe so optimum flow rates are maintained for the life of the system. Additionally by selecting the right plastic specification aggressive fluids and oils will not breakdown or effect the integral structure.
Given that metal pipes are subject to corrosion and attack from aggressive fluids a plastic pipe equivalent will hit this one right outside the ball park. Plastic pipe will last for many years. Most manufacturers will guarantee a life span of fifty years at least, probably by then the new today installation will have been torn down to make way for an improved layout.
There are some plastics that offer little in impact resistance particularly if they have been carrying hydrocarbon based products for any length of time. That is why we at Linmar often recommend ABS plastic pipe systems which have very high impact resistance and remains very durable even at low temperatures down to -40°c. Unaffected by hydrocarbon products even neat oil can be carried safely ABS will cover most applications.
Compared to metal pipes thermal expansion associated with plastic pipe installations are likely to be greater. On lengthy pipework runs this eventuality should be considered to ensure that snaking does not become a problem. It's easily dealt with as plastic pipe is extremely flexible so usually a directional change built in at strategic points will prevent thermal expansion from bending an otherwise straight pipe. Another option is to build in an expansion loop or use a flexible connection to allow pipes to expand and contract easily.