Information about plumbing with PEX tubing. How to connect PEX pipe, use PEX tools, make connections with PEX fittings..Find all types and sizes of PEX tubing for radiant heating, plumbing, snow melting or other application. Free fast shipping..Non barrier PEX plumbing tubing is used for hot and cold water plumbing applications and is lead free compliant. In stock and available in all sizes up to “..The difference between pipes and tubes is simply in the way it is sized. PVC pipe for plumbing applications and galvanized steel pipe for instance, are measured in .