Heating, air conditioning, and refrigeration mechanics and installers--often referred to as HVACR technicians--work on heating, ventilation, cooling, and refrigeration systems that control the air quality in many types of buildings.
Heating, air conditioning, and refrigeration mechanics and installers typically do the following:
Heating and air conditioning systems control the temperature, humidity, and overall air quality in homes, businesses, and other buildings. By providing a climate controlled environment, refrigeration systems make it possible to store and transport food, medicine, and other perishable items.
Although trained to do all three, HVACR technicians sometimes work strictly with heating, air conditioning, or refrigeration systems. They also may specialize in certain types of HVACR equipment, such as water-based heating systems, solar panels, or commercial refrigeration.
Depending on the task, HVACR technicians use many different tools. For example, they often use screwdrivers, wrenches, pipe cutters and other basic handtools when installing systems. To test or install complex system components, technicians may use more sophisticated tools, such as carbon monoxide testers, voltmeters, combustion analyzers, and acetylene torches.
When working on air conditioning and refrigeration systems, technicians must follow government regulations regarding the conservation, recovery, and recycling of refrigerants. This often entails proper handling and disposal of fluids.
Some HVACR technicians sell service contracts to their clients, providing regular maintenance of heating and cooling systems.
Other craft workers sometimes help install or repair cooling and heating systems. For example, on a large air conditioning installation job, especially one in which workers are covered by union contracts, ductwork might be done by sheet metal workers and duct installers, or electrical work by electricians. In addition, home appliance repairers usually service window air conditioners and household refrigerators. For more information on these occupations, see the profiles on sheet metal workers, electricians, or home appliance repairers.
Assemblers and fabricators assemble both finished products and the parts that go into them. They use tools, machines, and their hands to make engines, computers, aircraft, toys, electronic devices, and more.
Assemblers and fabricators typically do the following:
Assemblers and fabricators have an important role in the manufacturing process. They assemble both finished products and the pieces that go into them. The products encompass a full range of manufactured products, including aircraft, toys, household appliances, automobiles, computers, and electronic devices.
Changes in technology have transformed the manufacturing and assembly process. Modern manufacturing systems use robots, computers, programmable motion-control devices, and various sensing technologies. These systems change the way in which goods are made and affect the jobs of those who make them. Advanced assemblers must be able to work with these new technologies and use them to produce goods.
The job of an assembler or fabricator ranges from very easy to very complicated, requiring a range of knowledge and skills. Skilled assemblers putting together complex machines, for example, read detailed schematics or blueprints that show how to assemble the machine. After determining how parts should connect, they use hand or power tools to trim, shim, cut, and make other adjustments to fit components together and align them properly. Once the parts are properly aligned, they connect them with bolts and screws or weld or solder pieces together.
Quality control is important throughout the assembly process, so assemblers look for faulty components and mistakes in the assembly process. They help to fix problems before defective products are made.
Manufacturing techniques are moving away from traditional assembly line systems toward lean manufacturing systems, which use teams of workers to produce entire products or components. Lean manufacturing has changed the nature of the assemblers' duties.
It has become more common to involve assemblers and fabricators in product development. Designers and engineers consult manufacturing workers during the design stage to improve product reliability and manufacturing efficiency. Some experienced assemblers work with designers and engineers to build prototypes or test products.
Although most assemblers and fabricators are classified as team assemblers, others specialize in producing one type of product or do the same or similar tasks throughout the assembly process.
The following are types of assemblers and fabricators:
Aircraft structure, surfaces, rigging, and systems assemblers fit, fasten, and install parts of airplanes, space vehicles, or missiles, such as wings, fuselage, landing gear, rigging and control equipment, or heating and ventilating systems.
Coil winders, tapers, and finishers wind wire coils of electrical components used in a variety of electric and electronic products, including resistors, transformers, generators, and electric motors.
Electrical and electronic equipment assemblers build products such as electric motors, computers, electronic control devices, and sensing equipment. Automated systems have been put in place because many small electronic parts are too small or fragile for human assembly. Much of the remaining work of electrical and electronic assemblers is done by hand during the small-scale production of electronic devices used in all types of aircraft, military systems, and medical equipment. Production by hand requires these workers to use devices such as soldering irons.
Electromechanical equipment assemblers assemble and modify electromechanical devices such as household appliances, computer tomography scanners, or vending machines. The workers use a variety of tools, such as rulers, rivet guns, and soldering irons.
Engine and machine assemblers construct, assemble, or rebuild engines, turbines, and machines used in automobiles, construction and mining equipment, and power generators.
Structural metal fabricators and fitters cut, align, and fit together structural metal parts and may help weld or rivet the parts together.
Fiberglass laminators and fabricators laminate layers of fiberglass on molds to form boat decks and hulls, bodies for golf carts, automobiles, or other products.
Team assemblers work on an assembly line, but they rotate through different tasks, rather than specializing in a single task. The team may decide how the work is assigned and how different tasks are done. Some aspects of lean production, such as rotating tasks and seeking worker input on improving the assembly process, are common to all assembly and fabrication occupations.
Timing device assemblers, adjusters, and calibrators do precision assembling or adjusting of timing devices within very narrow tolerances.
Plumbers, pipefitters, and steamfitters install and repair pipes that carry water, steam, air, or other liquids or gases to and in businesses, homes, and factories.
Plumbers, pipefitters, and steamfitters typically do the following:
Although plumbers, pipefitters, and steamfitters are three distinct specialties, their duties are often similar. For example, they all install pipes and fittings that carry water, steam, air, or other liquids or gases. They connect pipes, determine the necessary materials for a job, and perform pressure tests to ensure a pipe system is airtight and watertight.
Plumbers, pipefitters, and steamfitters install, maintain, and repair many different types of pipe systems. Some of these systems carry water, dispose of waste, supply gas to ovens, or heat and cool buildings. Other systems, such as those in power plants, carry the steam that powers huge turbines. Pipes also are used in manufacturing plants to move acids, gases, and waste byproducts through the production process.
Master plumbers on construction jobs may be involved with developing blueprints that show where all the pipes and fixtures will go. Their input helps ensure that a structure's plumbing meets building codes, stays within budget, and works well with the location of other features, such as electric wires.
Plumbers and fitters may use many different materials and construction techniques, depending on the type of project. Residential water systems, for example, use copper, steel, and plastic pipe that one or two plumbers can install. Power-plant water systems, by contrast, are made of large steel pipes that usually take a crew of pipefitters to install. Some workers install stainless steel pipes on dairy farms and in factories, mainly to prevent contamination.
Plumbers and fitters sometimes cut holes in walls, ceilings, and floors. With some pipe systems, workers may hang steel supports from ceiling joists to hold the pipe in place. Because pipes are seldom manufactured to the exact size or length, plumbers and fitters measure and then cut and bend lengths of pipe as needed. Their tools include saws, pipe cutters, and pipe-bending machines.
They then connect the pipes, using methods that vary by type of pipe. For example, copper pipe is joined with solder, but steel pipe is often screwed together.
In addition to installation and repair work, journey- and master-level plumbers, pipefitters, and steamfitters often direct apprentices and helpers.
Following are examples of occupational specialties:
Plumbers install and repair water, drainage, and gas pipes in homes, businesses, and factories. They install and repair large water lines, such as those that supply water to buildings, and smaller ones, including ones that supply water to refrigerators. Plumbers also install plumbing fixtures--bathtubs, showers, sinks, and toilets--and appliances such as dishwashers, garbage disposals, and water heaters. They also fix plumbing problems. For example, when a pipe is clogged or leaking, plumbers remove the clog or replace the pipe. Some plumbers maintain septic systems, the large, underground holding tanks that collect waste from houses not connected to a city or county's sewer system.
Pipefitters install and maintain pipes that carry chemicals, acids, and gases. These pipes are mostly in manufacturing, commercial, and industrial settings. They often install and repair pipe systems in power plants, as well as heating and cooling systems in large office buildings. Some pipefitters specialize:
Welders, cutters, solderers, and brazers weld or join metal parts. They also fill holes, indentions, or seams of metal products, using hand-held welding equipment.
Welders, cutters, solderers, and brazers typically do the following:
Welding is the most common way of permanently joining metal parts. In this process, heat is applied to metal pieces, melting and fusing them to form a permanent bond. Because of its strength, welding is used in shipbuilding, automobile manufacturing and repair, aerospace applications, and thousands of other manufacturing activities. Welding also is used to join beams in the construction of buildings, bridges, and other structures and to join pipes in pipelines, power plants, and refineries.
Welders work in a wide variety of industries, from car racing to manufacturing. The work that welders do and the equipment they use vary, depending on the industry. The most common and simplest type of welding today, arc welding, uses electrical currents to create heat and bond metals together--but there are more than 100 different processes that a welder can use. The type of weld is normally determined by the types of metals being joined and the conditions under which the welding is to take place.
Cutters use heat to cut and trim metal objects to specific dimensions. The work of arc, plasma, and oxy-gas cutters is closely related to that of welders. However, instead of joining metals, cutters use the heat from an electric arc, a stream of ionized gas called plasma, or burning gases to cut and trim metal objects to specific dimensions. Cutters also dismantle large objects, such as ships, railroad cars, automobiles, buildings, or aircraft. Some operate and monitor cutting machines similar to those used by welding machine operators.
Solderers and brazers also use heat to join two or more metal items together. Soldering and brazing are similar, except the temperature used to melt the filler metal is lower in soldering. Soldering uses metals with a melting point below 840 degrees Fahrenheit. Brazing uses metals with a higher melting point.
Soldering and brazing workers use molten metal to join two pieces of metal. However, the metal added during the soldering and brazing process has a melting point lower than that of the piece, so only the added metal is melted, not the piece. Therefore, these processes normally do not create the distortions or weaknesses in the pieces that can occur with welding.
Soldering commonly is used to make electrical and electronic circuit boards, such as computer chips. Soldering workers tend to work with small pieces that must be precisely positioned.
Brazing often is used to connect copper plumbing pipes and thinner metals that the higher temperatures of welding would warp. Brazing also can be used to apply coatings to parts to reduce wear and protect against corrosion.
Sheet metal workers fabricate or install products that are made from thin metal sheets, such as ducts used for heating and air-conditioning.
Sheet metal workers typically do the following:
Sheet metal workers make, install, and maintain thin sheet metal products. Although sheet metal is used to make many products, such as rain gutters, outdoor signs, and siding, it is most commonly used to make ducts for heating and air-conditioning.
Sheet metal workers study plans and specifications to determine the kind and quantity of materials they will need. Using computer-controlled saws, lasers, shears, and presses, they measure, cut, bend, and fasten pieces of sheet metal.
In shops without computerized equipment, sheet metal workers make the required calculations and use tapes and rulers to lay out the work. Then, they cut or stamp the parts with machine tools.
In manufacturing plants, sheet metal workers program and operate computerized metalworking equipment. For example, they may make sheet metal parts for aircraft or industrial equipment. Sheet metal workers in those jobs may be responsible for programming the computer control systems of the equipment they operate.
Before assembling pieces, sheet metal workers check each part for accuracy. If necessary, they use hand, rotary, or squaring shears and hacksaws to finish pieces.
After inspecting the metal pieces, workers fasten seams and joints with welds, bolts, rivets, solder, or other connecting devices. Then they take the parts constructed in the shop and assemble the pieces further as they install them.
Most fabrication work is done in shops with some final assembly done on the job. Some jobs are done completely at the jobsite. When installing a metal roof, for example, sheet metal workers usually measure and cut the roofing panels onsite.
In addition to installing sheet metal, some workers install fiberglass and plastic board.
In some shops and factories, sheet metal workers care for and maintain the equipment they use.
Sheet metal workers do both construction-related work and the mass production of sheet metal products in manufacturing. Sheet metal workers are often separated into four specialties: fabrication, installation, maintenance, and testing and balancing. The following describes these types of sheet metal workers:
Fabrication sheet metal workers, sometimes called precision sheet metal workers, make ducts, gutters, and other metal products. Most work in shops and factories, operating tools and equipment. Although some of the fabrication techniques used in large-scale manufacturing are similar to those used in smaller shops, the work may be highly automated and repetitive. Many fabrication shops have automated machinery, and workers use computer-aided drafting (CAD) and building information modeling (BIM) systems to make products.
Installation sheet metal workers install heating, ventilation, and air-conditioning (HVAC) ducts. They also install other sheet metal products, such as metal roofs, siding, or gutters. They work on new construction and on renovation projects.
Maintenance sheet metal workers repair and clean ventilation systems so the systems use less energy. Workers remove dust and moisture and fix leaks or breaks in the sheet metal that makes up the ductwork.
Testing and balancing sheet metal specialists ensure that HVAC systems heat and cool rooms properly. They ensure that hot and cold air is transferred through sheet metal ducts efficiently. For more information on workers who install or repair HVAC systems, see the profile on heating, air conditioning, and refrigeration mechanics and installers.