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A pipefitter or steamfitteris 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).
Pipefitters install, assemble, fabricate, maintain, repair, and troubleshoot pipe carrying fuel, chemicals, water, steam, and air in heating, cooling, lubricating, and various other process piping systems. Pipefitters are employed in the maintenance departments of power stations, refineries, offshore installations, factories, and similar establishments, by pipefitting contractors.
In North America, union pipefitters are members of the United Association. Wages vary from area to area, based on demands for experienced personnel and existing contracts between local unions and contractors. The United Association is also affiliated with the piping trades unions in Ireland and Australia.
Pipefitters should not be confused with pipelayers. Both trades involve pipe and valves and both use some of the same tools.However, pipelayers usually work outside, laying pipe underground or on the seabed, whereas pipefitters typically work inside, installing piping in buildings, aeroplanes, or ships. One author summarizes the different tasks this way:
Pipe layers operate the backhoes and trenching machinery that dig the trenches to accommodate the placement of sanitary sewer pipes and stormwater sewer drainpipes. They use surveyor’s equipment to ensure the trenches have the proper slope and install the pieces of pipe in the trenches, joining the ends with cement, glue, or welding equipment. Using an always-open or always-closed valve called a tap, pipe layers connect them to a wider system and bury the pipes.
Pipe fitters plan and test piping and tubing layouts; cut, bend or fabricate pipe or tubing segments; and join those segments by threading them, using lead joints, welding, brazing, cementing, or soldering them together. They install manual, pneumatic, hydraulic and electric valves in pipes to control the flow through the pipes or tubes. These workers create the system of tubes in boilers and make holes in walls and bulkheads to accommodate the passage of the pipes they install.
Pipe fitters are often exposed to hazardous or dangerous materials, such as asbestos, lead, ammonia, steam, flammable gases, various resins and solvents including benzene and various refrigerants. Much progress was made in the 20th century toward eliminating or reducing hazardous materials exposures. Many aspects of hazardous materials are now regulated by law in most countries, including asbestos usage and removal and refrigerant selection and handling.
Other occupational hazards include exposure to the weather, heavy lifting, crushing hazards, lacerations, and other risks normal to the construction industry.
Plumbing is any system that conveys fluids for a wide range of applications. Plumbing uses pipes, valves, plumbing fixtures, tanks, and other apparatuses to convey fluids. Heating and cooling (HVAC), waste removal, and potable water delivery are among the most common uses for plumbing, but it is not limited to these applications. The word derives from the Latin for lead, plumbum, as the first effective pipes used in the Roman era were lead pipes.
A plumber is a tradesperson who specializes in installing and maintaining systems used for potable (drinking) water, and for sewage and drainage in plumbing systems.
A millwright is a craftsperson or skilled tradesperson who installs, dismantles, maintains, repairs, reassembles, and moves machinery in factories, power plants, and construction sites.
Within industry, piping is a system of pipes used to convey fluids from one location to another. The engineering discipline of piping design studies the efficient transport of fluid.
A compression fitting is a fitting used in plumbing and electrical conduit systems to join two tubes or thin-walled pipes together. In instances where two pipes made of dissimilar materials are to be joined, the fittings will be made of one or more compatible materials appropriate for the connection. Compression fittings for attaching tubing (piping) commonly have ferrules in them, and are sometimes referred to as flareless fittings. There are also flare fittings that do not require ferrules/olives.
A pipe is a tubular section or hollow cylinder, usually but not necessarily of circular cross-section, used mainly to convey substances which can flow — liquids and gases (fluids), slurries, powders and masses of small solids. It can also be used for structural applications; hollow pipe is far stiffer per unit weight than solid members.
In piping and plumbing, a coupling is a very short length of pipe or tube, with a socket at one or both ends that allows two pipes or tubes to be joined, welded (steel), brazed or soldered together.
A fitting or adapter is used in pipe systems to connect straight sections of pipe or tube, adapt to different sizes or shapes, and for other purposes such as regulating fluid flow. These fittings are used in plumbing to manipulate the conveyance of water, gas, or liquid waste in domestic or commercial environments, within a system of pipes or tubes.
The United Association of Journeymen and Apprentices of the Plumbing and Pipe Fitting Industry of the United States and Canada, commonly known as the United Association (UA), is a labor union which represents workers in the plumbing and pipefitting industries in the United States and Canada.
Hull maintenance technician is a United States Navy occupational rating.
A direct exchange (DX) geothermal heat pump is a type of ground source heat pump in which refrigerant circulates through copper tubing placed in the ground unlike other ground source heat pumps where refrigerant is restricted to the heat pump itself with a secondary loop in the ground filled with a mixture of water and anti-freeze.
Plastic pipe is a tubular section, or hollow cylinder, made of plastic. It is usually, but not necessarily, of circular cross-section, used mainly to convey substances which can flow—liquids and gases (fluids), slurries, powders and masses of small solids. It can also be used for structural applications; hollow pipes are far stiffer per unit weight than solid members.
Soldering is a process in which two or more items are joined by melting and putting a filler metal (solder) into the joint, the filler metal having a lower melting point than the adjoining metal. Unlike welding, soldering does not involve melting the work pieces. In brazing, the work piece metal also does not melt, but the filler metal is one that melts at a higher temperature than in soldering. In the past, nearly all solders contained lead, but environmental and health concerns have increasingly dictated use of lead-free alloys for electronics and plumbing purposes.
A tube, or tubing, is a long hollow cylinder used for moving fluids or to protect electrical or optical cables and wires.
Pin brazing is an easy, metallurgically safe method of making electrical connections to steel and ductile iron pipelines as well as other metallic structures, which are to be cathodically protected or electrically earthed.
A pipe support or pipe hanger is a designed element that transfer the load from a pipe to the supporting structures. The load includes the weight of the pipe proper, the content that the pipe carries, all the pipe fittings attached to pipe, and the pipe covering such as insulation. The four main functions of a pipe support are to anchor, guide, absorb shock, and support a specified load. Pipe supports used in high or low temperature applications may contain insulation materials. The overall design configuration of a pipe support assembly is dependent on the loading and operating conditions.
Copper tubing is most often used for heating systems and as a refrigerant line in HVAC systems. Copper tubing is slowly being replaced by PEX tubing in hot and cold water applications. There are two basic types of copper tubing, soft copper and rigid copper. Copper tubing is joined using flare connection, compression connection, pressed connection, or solder. Copper offers a high level of corrosion resistance but is becoming very costly.
A pipelayer is a skilled tradesman who lays pipe, such as for storm sewers, sanitary sewers, drains, and water mains. Pipelayers may grade trenches and culverts, position pipe, or seal joints. The Standard Occupational Classification System code for pipelayers is 47-2151.
A wiped joint is a form of soldered joint used to join lead pipework.