In the model codes, tubing used for the hot and cold water distribution lines must both be rated for such use (eg. rollmarked 180F / 100 psi).

This was done, if you believe the rumors, in case the plumber somehow crossed the hot and cold lines, both tubing would be rated for hot water.

PVC is therefore, used as "service line" or "main to building supply" and DWV piping. PVC would make just dandy cold water pipes inside the house but codes generally don't allow for this practice - plus they don't make a CTS "copper tube sized" version. PVC really isn't very much different otherwise. Service lines basically see a great deal of stress, and slow leaks are a serious issue nationwide, regardless of material.

CPVC is a modified PVC resin - made to resist higher temperatures. PVC pressure use temperature max is 140F, CPVC 180F.

CPVC used in sprinkler systems (and all sprinkler components) are tested to two times pressures used in ordinary plumbing systems. Last I heard a sample tested to distruction burst over 2000 psi.

All hot water tubing BTW is tested to resist 210F/150 psi conditions - as in a run away T&P valve for at least 48 hours. Some do so for a month.

As to color, some primers are more violet then "purple", but the cements manufactured for CPVC should be orange or yellow. Yellow cements are typically low VOC one step cements and may be used as such where permitted.

Michael Cudahy
Codes and Training
Plastic Pipe and Fittings Association