PBT – flexible (usually gray or black) plastic pipe which is attached to barbed fittings and secured in place with a copper crimp ring. The primary manufacturer of PBT tubing and fittings was driven into bankruptcy by a class-action lawsuit over failures of this system. However, PB and PBT tubing has since returned to the market and codes, typically first for "exposed locations" such as risers.
Journeyman plumber: Once the requirements of an apprenticeship are fulfilled, plumbers can apply for a journeyman license. Many workers in the plumbing industry are journeymen. Obtaining a journeyman's license requires a fee and the successful passing of an exam. Licenses vary by state, although not all areas require journeymen to be licensed. Instead, the amount of work they are able to perform is limited.