text: A pipefitter or steamfitter is a tradesman who installs, assembles, fabricates, maintains, and repairs mechanical piping systems. Pipefitters usually begin as helpers or apprentices. Journeyman pipefitters deal with industrial/commercial/marine piping and heating/cooling systems. Typical industrial process pipe is under high pressure, which requires metals such as carbon steel, stainless steel, and many different alloy metals fused together through precise cutting, threading, grooving, bending, and welding. A plumber concentrates on lower pressure piping systems for sewage and potable tap water in the industrial, commercial, institutional, or residential atmosphere. Utility piping typically consists of copper, PVC, CPVC, polyethylene, and galvanized pipe, which is typically glued, soldered, or threaded. Other types of piping systems include steam, ventilation, hydraulics, chemicals, fuel, and oil.
  In Canada, pipefitting is classified as a compulsory trade, and carries a voluntary "red seal" inter-provincial standards endorsement. Pipefitter apprenticeships are controlled and regulated provincially, and in some cases allow for advance standing in similar trades upon completion.
  In the United States, many states require pipefitters to be licensed. Requirements differ from state to state, but most include a four- to five-year apprenticeship. Union pipefitters are required to pass an apprenticeship test (often called a "turn-out exam") before becoming a licensed journeyman. Others can be certified by NCCER (formerly the National Center for Construction Education and Research).