Plastic pipe is increasingly popular in a wide range of residential, industrial and commercial applications. The two most common types of plastic pipe used in these applications are PVC and CPVC pipe.
PVC pipe or polyvinyl chloride has been used for a long time in all types of applications. It is non-corrosive and non-reactive, and it is strong and durable, and also much lower cost than metal piping. PVC is considered to be a thermal plastic, which means it is easy to melt and form, making this a cheap option to produce long lengths of pipe as well as the more complex fittings.
CPVC pipe is related to PVC pipe, as can be expected, but it is also very different. It has a chemical and molecular difference that includes a free radical chlorination process and reaction, which boosts the level of chlorine in the plastic. This increase in the chlorine in the chemical composition of CPVC fittings and pipe makes them a better match for hot water applications where PVC pipe is not designed to be used.
The Heat Factor
The choice of CPVC fittings and pipe is common when the water or liquid temperature in the system will exceed 140 degrees Fahrenheit. Below that, PVC is the most commonly used option.
It is important to realize that CPVC fittings and pipe also have their maximum heat range as well. This is at 200 degrees Fahrenheit, and above this, the joints and the actual pipe and fittings can become soft, leading to possible pipe or fitting failure, particularly with repeated heating and cooling above the recommended temperatures.
It is essential to avoid mixing CPVC and PVC pipe and fittings in any type of application. Not only are there heat tolerance differences, but different primers and solvents may be required during system installation.