CPVC and PVC are made of the same basic elements, but CPVC is altered by a free radical chlorination reaction that increases its chlorine content and allows it to withstand a wider range of temperatures. PEX piping was not listed in a 2017 technical note issued by the Plastic Pipe Institute (PPI) as being able to perform under temperature ratings of 180°F and pressure ratings of 100psi in the presence of chlorinated water.