Hydrologists

Hydrologists study water and the water cycle. They study the movement, distribution, and other properties of water, and they analyze how these influence the surrounding environment. They use their expertise to solve problems concerning water quality and availability, for example.

Hydrologists typically do the following:

  • Measure the properties of bodies of water, such as volume and stream flow
  • Collect water and soil samples to test for certain properties, such as levels of pollution
  • Apply research findings to help minimize the environmental impacts of pollution, erosion, and other problems
  • Research ways to improve water conservation and preservation
  • Use computer models to forecast future water supplies, the spread of pollution, and other events
  • Evaluate the feasibility of water-related projects, such as hydroelectric power plants, irrigation systems, and waste treatment facilities
  • Prepare written reports and presentations of their findings

Hydrologists use remote sensing equipment to collect data. They or technicians whom they supervise usually install and maintain this equipment.

They also use sophisticated computer programs to analyze and model data. They use sophisticated laboratory equipment to analyze chemical samples collected in the field.

Hydrologists work closely with engineers, scientists, and public officials to study and manage the water supply. For example, they work with policy makers to develop water conservation plans and with biologists to monitor marine wildlife.

Most hydrologists specialize in a specific water source or a certain aspect of the water cycle, such as the evaporation of water from lakes and streams. Some of the most common specialties are:

Groundwater hydrologists study the water below the Earth's surface. They decide the best locations for wells and the amount of water that should be pumped. They are often consulted about the best places to build waste disposal sites to ensure that the waste does not contaminate the groundwater.

Hydrometeorologists study the relationship between surface waters and water in the atmosphere. For example, to predict and prepare for droughts, they study how much rain or snow a particular area gets and how that evaporates.

Surface water hydrologists study water from above ground sources such as streams, lakes, and snow packs. They may predict future water levels and usage to help reservoir managers decide when to release or store water. They also produce flood forecasts and help develop flood management plans.

Some people with a hydrology background become professors or teachers. For more information, see the profile on postsecondary teachers.


Roofers

Roofers repair and install the roofs of buildings using a variety of materials, including shingles, asphalt, and metal.

Roofers typically do the following:

  • Inspect problem roofs to determine the best way to repair them
  • Measure roof to calculate the quantities of materials needed
  • Replace damaged or rotting joists or plywood
  • Install vapor barriers or layers of insulation
  • Install shingles, asphalt, metal, or other materials to make the roof watertight
  • Align roofing materials with edges of the roof
  • Cut roofing materials to fit angles formed by walls, vents, or intersecting roof surfaces
  • Cover exposed nail or screw heads with roofing cement or caulk to prevent leakage

Properly installed roofs keep water from leaking into buildings and damaging the interior, equipment, or furnishings.

There are two basic types of roofs, low-slope and steep-slope:

  • Low-slope: About two-thirds of all roofs are low-slope. Most commercial, industrial, and apartment buildings have low-slope roofs. Low-slope roofs rise 4 inches or less per horizontal foot and are installed in layers.

    For low-slope roofs, roofers typically use several layers of roofing materials or felt membranes stuck together with hot bitumen (a tar-like substance). They glaze the top layer to make a smooth surface or embed gravel in the hot bitumen to make a rough surface.

    An increasing number of low-slope roofs are covered with a single-ply membrane of waterproof rubber or thermoplastic compounds.
  • Steep-slope: Most of the remaining roofs are steep-slope. Most single-family houses have steep-slope roofs. Steep-slope roofs rise more than 4 inches per horizontal foot.

    For steep-slope roofs, roofers typically use asphalt shingles, which often cost less than other coverings. On steep-slope roofs, some roofers also install tile, solar shingles, fiberglass shingles, metal shingles, or shakes (rough wooden shingles).

    To apply shingles, roofers first lay, cut, and tack 3-foot strips of roofing over the entire roof. Then, starting from the bottom edge, they nail overlapping rows of shingles to the roof.

A small but increasing number of buildings now have “green” roofs that incorporate landscape roofing systems. A landscape roofing system typically begins with a single or multiple waterproof layers. After that layer is proven to be leak free, roofers put a root barrier over it, and, finally, layers of soil, in which vegetation is planted. Roofers must ensure that the roof is watertight and can endure the weight and water needs of the plants.


Heating, Air Conditioning, and Refrigeration Mechanics and Installers

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:

  • Travel to worksites
  • Follow blueprints or other design specifications to install or repair HVACR systems
  • Connect systems to fuel and water supply lines, air ducts, and other components
  • Install electrical wiring and controls and test for proper operation
  • Inspect and maintain customers' HVACR systems
  • Test individual components to determine necessary repairs
  • Repair or replace worn or defective parts

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.


Carpenters

Carpenters construct and repair building frameworks and structures--such as stairways, doorframes, partitions, and rafters--made from wood and other materials. They also may install kitchen cabinets, siding, and drywall.

Carpenters typically do the following:

  • Follow blueprints and building plans to meet the needs of clients
  • Install structures and fixtures, such as windows and molding
  • Measure, cut, or shape wood, plastic, fiberglass, drywall, and other materials
  • Construct building frameworks, including wall studs, floor joists, and doorframes
  • Help put up, level, and install building framework with the aid of large pulleys and cranes
  • Inspect and replace damaged framework or other structures and fixtures
  • Instruct and direct laborers and other construction trade helpers

Carpenters are one of the most versatile construction occupations, with workers usually doing a variety of tasks. For example, some carpenters insulate office buildings; others install drywall or kitchen cabinets in homes. Those who help construct large buildings or bridges often make the wooden concrete forms for cement footings or pillars. Some carpenters build braces and scaffolding for buildings.

Carpenters use many different hand and power tools to cut and shape wood, plastic, fiberglass, or drywall. They commonly use handtools, including squares, levels, and chisels, as well as many power tools, such as sanders, circular saws, and nail guns. Carpenters put materials together with nails, screws, staples, and adhesives, and do a final check of their work to ensure accuracy. They use a tape measure on every project because proper measuring increases productivity, reduces waste, and ensures that the pieces being cut are the proper size.

The following are types of carpenters:

Residential carpenters typically specialize in new-home, townhome, and condominium building and remodeling. As part of a single job, they might build and set forms for footings, walls and slabs, and frame and finish exterior walls, roofs, and decks. They frame interior walls, build stairs, and install drywall, crown molding, doors, and kitchen cabinets. Highly-skilled carpenters may also tile floors and lay wood floors and carpet. Fully-trained construction carpenters are easily able to switch from new-home building to remodeling.

Commercial carpenters typically remodel and help build commercial office buildings, hospitals, hotels, schools, and shopping malls. Some specialize in working with light gauge and load-bearing steel framing for interior partitions, exterior framing, and curtain wall construction. Others specialize in working with concrete forming systems and finishing interior and exterior walls, partitions, and ceilings. Highly skilled carpenters can usually do many of the same tasks as residential carpenters.

Industrial carpenters typically work in civil and industrial settings where they put up scaffolding and build and set forms for pouring concrete. Some industrial carpenters build tunnel bracing or partitions in underground passageways and mines to control the circulation of air to worksites. Others build concrete forms for tunnels, bridges, dams, power plants, or sewer construction projects.


Hazardous Materials Removal Workers

Hazardous materials (hazmat) removal workers identify and dispose of asbestos, radioactive and nuclear waste, arsenic, lead, and other hazardous materials. They also clean up materials that are flammable, corrosive, reactive, or toxic.

Hazmat removal workers typically do the following:

  • Comply with safety procedures and federal laws regarding waste disposal
  • Construct scaffolding or build containment areas before cleaning up
  • Remove or clean up hazardous materials that are found or spilled
  • Clean contaminated equipment for reuse
  • Operate equipment that removes and stores waste materials
  • Keep records of cleanup activities

Hazmat removal workers clean up materials that are harmful to people and the environment. The work they do depends on the substances they are cleaning. Removing lead and asbestos is different from cleaning up radiation contamination and toxic spills. Differences also can relate to why these workers have been called in to clean a site. For example, cleaning up a fuel spill from a train derailment is more urgent than removing lead paint from a bridge.

The following are types of hazmat removal workers:

Asbestos abatement workers and lead abatement workers remove asbestos and lead from buildings that are going to be fixed up or taken down. Most of this work is in older buildings that were originally built with asbestos insulation and lead-based paints--both of which are now banned from being used in newer buildings and must be removed from older ones.

Until the 1970s, asbestos was often used in buildings for fireproofing, insulation, and other uses. However, asbestos particles can cause deadly lung diseases. Similarly, until the 1970s, lead was commonly used in paint, pipes, and plumbing fixtures. Inhaling lead dust or ingesting chips of lead-based paint can cause serious health problems, though, especially in children.

Lead abatement workers use chemicals and may need to know how to operate sandblasters, high-pressure water sprayers, and other common tools.

Decommissioning and decontamination workers remove and treat radioactive materials generated by nuclear facilities and powerplants. They break down contaminated items such as “gloveboxes,” which are used to process radioactive materials. When a facility is being closed or decommissioned (taken out of service), these workers clean the facility and decontaminate it from radioactive materials.

Decontamination technicians do tasks similar to those of janitors and cleaners, but the items and areas they clean are radioactive. Some of these jobs are now being done by robots controlled by people away from the contamination site. Increasingly, many of these remote devices automatically monitor and survey floors and walls for contamination.

Emergency and disaster response workers must work quickly to clean up hazardous materials after train and trucking accidents. Immediate, thorough cleanups help to control and prevent more damage to accident or disaster sites.

Radiation-protection technicians use radiation survey meters and other remote devices to locate and assess the hazard associated with radiated materials, operate high-pressure cleaning equipment for decontamination, and package radioactive materials for moving or disposing.

Treatment, storage, and disposal workers transport and prepare materials for treatment, storage, or disposal. To ensure proper treatment of materials, workers must follow laws enforced by the U.S. Environmental Protection Agency (EPA) or the U.S. Occupational Safety and Health Administration (OSHA). At incinerator facilities, treatment, storage, and disposal workers move materials from the customer or service center to the incinerator. At landfills, they organize and track the location of items in the landfill and may help change the state of a material from liquid to solid to prepare it to be stored. These workers typically operate heavy machinery, such as forklifts, earthmoving machinery, and large trucks and rigs.

Mold remediation makes up a small segment of hazardous materials removal work. Although mold is present in almost all structures and is not usually defined as a hazardous material, some mold--especially the types that cause allergic reactions--can infest a building to such a degree that extensive efforts must be taken to remove it safely.


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