Smart Technical Systems Inc

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.

Construction laborers and helpers do many basic tasks that require physical labor on construction sites.

Construction laborers and helpers typically do the following:

• Clean and prepare construction sites by removing debris and possible hazards
• Load or unload building materials to be used in construction
• Build or take apart bracing, barricades, forms (molds that determine the shape of concrete), scaffolding, and temporary structures
• Dig trenches, backfill holes, or compact earth to prepare for construction
• Operate or tend equipment and machines used in construction, such as concrete mixers
• Help other craftworkers with their duties
• Follow construction plans and instructions from the people they are working for

Construction laborers and helpers work on almost all construction sites, doing a wide range of tasks from the very easy to the extremely difficult and hazardous. Although many of the tasks they do require some training and experience, most jobs usually require little skill and can be learned quickly. 

The following are occupational specialties:

Construction laborers do a variety of construction-related activities during all phases of construction. Although most laborers are generalists--such as those who install barricades, cones, and markers to control traffic patterns--many others specialize. For example, those who operate the machines and equipment that lay concrete or asphalt on roads are more likely to specialize in those areas.

Most construction laborers work in the following areas:

• Building homes and businesses
• Tearing down buildings
• Removing hazardous materials
• Building highways and roads
• Digging tunnels and mine shafts

Construction laborers use a variety of tools and equipment. Some tools are simple, such as brooms and shovels; other equipment is more sophisticated, such as pavement breakers, jackhammers, earth tampers, and surveying equipment.

With special training, laborers may help transport and use explosives or run hydraulic boring machines to dig out tunnels. They may learn to use laser beam equipment to place pipes and use computers to control robotic pipe cutters. They may become certified to remove asbestos, lead, or chemicals.

Helpers assist construction craftworkers, such as electricians and carpenters, with a variety of basic tasks. They may carry tools and materials or help set up equipment. For example, many helpers work with cement masons to move and set forms. Many other helpers assist with taking apart equipment, cleaning up sites, and disposing of waste, as well as helping with any other needs of craftworkers.

Many construction trades have helpers who assist craftworkers. The following are examples of trades that have associated helpers:

• Brickmasons, blockmasons, stonemasons, and tile and marble setters
• Carpenters
• Electricians
• Painters, paperhangers, plasterers, and stucco masons
• Pipelayers, plumbers, pipefitters, and steamfitters
• Roofers

Cost estimators collect and analyze data to estimate the time, money, resources, and labor required for product manufacturing, construction projects, or services. Some specialize in a particular industry or product type.

Cost estimators typically do the following:

• Consult with industry experts to discuss estimates and resolve issues
• Identify and quantify cost factors, such as production time and raw material, equipment, and labor expenses
• Travel to job sites to gather information on materials needed, labor requirements, and other factors 
• Read blueprints and technical documents to prepare estimates
• Collaborate with engineers, architects, owners, and contractors on estimates
• Use sophisticated computer software to calculate estimates 
• Evaluate a product's cost effectiveness or profitability
• Recommend ways to make a product more cost effective or profitable
• Prepare estimates for clients and other business managers
• Develop project plans for the duration of the project

Accurately predicting the cost, size, and duration of future construction and manufacturing projects is vital to the survival of any business. Cost estimators' calculations give managers or investors this information.

When making calculations, estimators analyze many inputs to determine how much time, money, and labor a project needs, or how profitable it will be. These estimates have to take many factors into account, including allowances for wasted material, bad weather, shipping delays, and other factors that can increase costs and lower profitability.

Cost estimators use sophisticated computer software, including database, simulation, and complex mathematical programs. Cost estimators often use a computer database with information on the costs of other similar projects.

General contractors usually hire cost estimators for specific parts of a large construction project, such as estimating the electrical work or the excavation phase. In such cases, the estimator calculates the cost of the construction phase for which the contractor is responsible, rather than calculating the cost of the entire project. The general contractor usually also has a cost estimator who calculates the total project cost by analyzing the bids that the subcontractors' cost estimators prepared.

Some estimators are hired by manufacturers to analyze certain products or processes.

The following are the two primary types of cost estimators:

Construction cost estimators estimate construction work. More than half of all cost estimators work in the construction industry. They may, for example, estimate the total cost of building a bridge or a highway. They may identify direct costs, such as raw materials and labor requirements, and set a timeline for the project. Although many work directly for construction firms, some work for contractors, architects, and engineering firms.

Manufacturing cost estimators calculate the costs of developing, producing, or redesigning a company's goods and services. For example, a cost estimator working for a home appliance manufacturer may determine whether a new type of dishwasher will be profitable to manufacture.

Some manufacturing cost estimators work in software development. Many high-technology products require a considerable amount of computer programming, and the costs of software development are difficult to calculate.  

Two other groups also sometimes do cost estimating in their jobs. Operations research, production control, cost, and price analysts who work for government agencies may do significant amounts of cost estimating in the course of their usual duties. Construction managers also may spend considerable time estimating costs. For more information, see the profiles on operations research analysts and construction managers.

Sales managers direct organizations' sales teams. They set sales goals, analyze data, and develop training programs for the organization's sales representatives.

Sales managers typically do the following:

• Oversee regional and local sales managers and their staffs
• Resolve customer complaints regarding sales and service
• Prepare budgets and approve budget expenditures
• Monitor customer preferences to determine the focus of sales efforts
• Analyze sales statistics
• Project sales and determine the profitability of products and services
• Determine discount rates or special pricing plans
• Plan and coordinate training programs for sales staff

Sales managers' responsibilities vary with the size of the organization they work for. However, most sales managers direct the distribution of goods and services by assigning sales territories, setting sales goals, and establishing training programs for the organization's sales representatives.

In some cases, they recruit, hire, and train new members of the sales staff. For more information about sales workers, see the profiles on retail sales workers and wholesale and manufacturing sales representatives.

Sales managers advise sales representatives on ways to improve their sales performance. In large multiproduct organizations, they oversee regional and local sales managers and their staffs.

Sales managers also stay in contact with dealers and distributors. They analyze sales statistics that their staff gathers, both to determine the sales potential and inventory requirements of products and stores and to monitor customers' preferences.

Sales managers work closely with managers from other departments. For example, the marketing department identifies new customers that the sales department can target. The relationship between these two departments is critical to helping an organization expand its client base. Because sales managers monitor customers' preferences and stores' and organizations' inventory needs, they work closely with research and design departments and warehousing departments.

Construction and building inspectors ensure that new construction, changes, or repairs comply with local and national building codes and ordinances, zoning regulations, and contract specifications.

Construction and building inspectors typically do the following:

• Review and approve plans that meet building codes, local ordinances, and zoning regulations
• Inspect and monitor construction sites to ensure overall compliance
• Use survey instruments, metering devices, and test equipment to perform inspections
• Monitor installation of plumbing, electrical, and other systems to ensure that the building meets codes
• Verify level, alignment, and elevation of structures and fixtures to ensure building compliance
• Issue violation notices and stop-work orders until building is compliant
• Keep daily logs, including photographs taken during inspection

Construction and building inspectors examine buildings, highways and streets, sewer and water systems, dams, bridges, and other structures. They also inspect electrical; heating, ventilation, air-conditioning, and refrigeration (HVACR); and plumbing systems. Although no two inspections are alike, inspectors do an initial check during the first phase of construction and follow-up inspections throughout the construction project. When the project is finished, they do a final, comprehensive inspection.

The following are types of construction and building inspectors:

Building inspectors check the structural quality and general safety of buildings. Some specialize in structural steel or reinforced-concrete structures, for example.

Electrical inspectors examine the installed electrical systems to ensure they function properly and comply with electrical codes and standards. The inspectors visit worksites to inspect new and existing sound and security systems, wiring, lighting, motors, and generating equipment. They also inspect the installed electrical wiring for HVACR systems and appliances.

Elevator inspectors examine lifting and conveying devices, such as elevators, escalators, moving sidewalks, lifts and hoists, inclined railways, ski lifts, and amusement rides.

Home inspectors typically inspect newly built or previously owned homes, condominiums, townhomes, and other dwellings. Prospective home buyers often hire home inspectors to check and report on a home's structure and overall condition. Sometimes, homeowners hire a home inspector to evaluate their home's condition before placing it on the market.

In addition to examining structural quality, home inspectors examine all home systems and features, including roofing, exterior walls, attached garage or carport, foundation, interior, plumbing, electrical, and HVACR systems. They look for and report violations of building codes, but they do not have the power to enforce compliance with the codes.

Mechanical inspectors examine the installation of HVACR systems and equipment to ensure that they are installed and function properly. They also may inspect commercial kitchen equipment, gas-fired appliances, and boilers.

Plan examiners determine whether the plans for a building or other structure comply with building codes. They also determine whether the structure is suited to the engineering and environmental demands of the building site.

Plumbing inspectors examine the installation of potable water, waste, and vent piping systems to ensure the safety and health of the drinking water system, piping for industrial uses, and the sanitary disposal of waste.

Public works inspectors ensure that federal, state, and local government water and sewer systems, highways, streets, bridges, and dam construction conform to detailed contract specifications. Workers inspect excavation and fill operations, the placement of forms for concrete, concrete mixing and pouring, asphalt paving, and grading operations. Public works inspectors may specialize in highways, structural steel, reinforced concrete, or ditches. Others specialize in dredging operations required for bridges and dams or for harbors.

Specification inspectors ensure that work is performed according to design specifications. Specification inspectors represent the owner's interests, not those of the general public. Insurance companies and financial institutions also may use their services.

A primary concern of building inspectors is fire prevention safety. For more information, see the profile on fire inspectors and investigators.

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.

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.

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.

Health and safety engineers develop procedures and design systems to keep people from getting sick or injured and to keep property from being damaged. They combine a knowledge of health or safety and of systems engineering to make sure that chemicals, machinery, software, furniture, and other products are not going to cause harm to people or buildings.

Health and safety engineers typically do the following:

• Review plans and specifications for new machinery or equipment to make sure it meets safety requirements
• Inspect facilities, machinery, and safety equipment to identify and correct potential hazards
• Evaluate the effectiveness of various industrial control mechanisms
• Ensure that a building or product complies with health and safety regulations, especially after an inspection that required changes
• Install safety devices on machinery or direct the installation of these devices
• Review employee safety programs and recommend improvements
• Maintain and apply their knowledge of current policies, regulations, and industrial processes

Health and safety engineers also investigate industrial accidents, injuries, or occupational diseases to determine their causes and to see whether they could have been or can be prevented. They interview employers and employees to learn about work environments and incidents leading up to accidents or injuries. They also evaluate the corrections that were made to remedy violations found during health inspections.

Health and safety engineers are also active in two related fields: industrial hygiene and occupational hygiene. 

In industrial hygiene, they focus on the effects of chemical, physical, and biological agents. They recognize, evaluate, and control these agents to keep people from getting sick or injured. For example, they might anticipate that a particular manufacturing process will give off a potentially harmful chemical and recommend either a change to the process or a way to contain and control the chemical.  

In occupational hygiene, health and safety engineers investigate the environment in which people work and use science and engineering to recommend changes to keep workers from being exposed to sickness or injuries. They help employers and employees understand the risks and improve working conditions and working practices. For example, they might observe that the noise level in a factory is likely to cause short-term and long-term harm to workers and recommend ways to reduce the noise level through changes to the building or by having workers wear strong headphones.

Health and safety engineering is a broad field covering many activities. The following are specific types of health and safety engineers:

Aerospace safety engineers work on missiles, radars, and satellites to make sure that they function safely as designed.

Fire prevention and protection engineers design fire prevention systems for all kinds of buildings. They often work for architects during the design phase of new buildings or renovations. They must be licensed, and they must keep up with changes in fire codes and regulations.

Product safety engineers investigate the causes of accidents or injuries that might have resulted from the use or misuse of a product. They propose solutions to reduce or eliminate any safety issues associated with products. They also participate in the design phase of new products to prevent injuries, illnesses, or property damage that could occur with the use of the product.

Systems safety engineers work in many fields, including aerospace, and are moving into new fields, such as software safety, medical safety, and environmental safety. These engineers take a systemic approach to identify hazards in these new fields so that accidents and injuries can be avoided.

For information on health and safety engineers who work in mines, see the profile on mining and geological engineers.

Construction and building inspectors ensure that new construction, changes, or repairs comply with local and national building codes and ordinances, zoning regulations, and contract specifications.

Construction and building inspectors typically do the following:

• Review and approve plans that meet building codes, local ordinances, and zoning regulations
• Inspect and monitor construction sites to ensure overall compliance
• Use survey instruments, metering devices, and test equipment to perform inspections
• Monitor installation of plumbing, electrical, and other systems to ensure that the building meets codes
• Verify level, alignment, and elevation of structures and fixtures to ensure building compliance
• Issue violation notices and stop-work orders until building is compliant
• Keep daily logs, including photographs taken during inspection

Construction and building inspectors examine buildings, highways and streets, sewer and water systems, dams, bridges, and other structures. They also inspect electrical; heating, ventilation, air-conditioning, and refrigeration (HVACR); and plumbing systems. Although no two inspections are alike, inspectors do an initial check during the first phase of construction and follow-up inspections throughout the construction project. When the project is finished, they do a final, comprehensive inspection.

The following are types of construction and building inspectors:

Building inspectors check the structural quality and general safety of buildings. Some specialize in structural steel or reinforced-concrete structures, for example.

Electrical inspectors examine the installed electrical systems to ensure they function properly and comply with electrical codes and standards. The inspectors visit worksites to inspect new and existing sound and security systems, wiring, lighting, motors, and generating equipment. They also inspect the installed electrical wiring for HVACR systems and appliances.

Elevator inspectors examine lifting and conveying devices, such as elevators, escalators, moving sidewalks, lifts and hoists, inclined railways, ski lifts, and amusement rides.

Home inspectors typically inspect newly built or previously owned homes, condominiums, townhomes, and other dwellings. Prospective home buyers often hire home inspectors to check and report on a home's structure and overall condition. Sometimes, homeowners hire a home inspector to evaluate their home's condition before placing it on the market.

In addition to examining structural quality, home inspectors examine all home systems and features, including roofing, exterior walls, attached garage or carport, foundation, interior, plumbing, electrical, and HVACR systems. They look for and report violations of building codes, but they do not have the power to enforce compliance with the codes.

Mechanical inspectors examine the installation of HVACR systems and equipment to ensure that they are installed and function properly. They also may inspect commercial kitchen equipment, gas-fired appliances, and boilers.

Plan examiners determine whether the plans for a building or other structure comply with building codes. They also determine whether the structure is suited to the engineering and environmental demands of the building site.

Plumbing inspectors examine the installation of potable water, waste, and vent piping systems to ensure the safety and health of the drinking water system, piping for industrial uses, and the sanitary disposal of waste.

Public works inspectors ensure that federal, state, and local government water and sewer systems, highways, streets, bridges, and dam construction conform to detailed contract specifications. Workers inspect excavation and fill operations, the placement of forms for concrete, concrete mixing and pouring, asphalt paving, and grading operations. Public works inspectors may specialize in highways, structural steel, reinforced concrete, or ditches. Others specialize in dredging operations required for bridges and dams or for harbors.

Specification inspectors ensure that work is performed according to design specifications. Specification inspectors represent the owner's interests, not those of the general public. Insurance companies and financial institutions also may use their services.

A primary concern of building inspectors is fire prevention safety. For more information, see the profile on fire inspectors and investigators.

Occupational health and safety technicians collect data on the safety and health conditions of the workplace. Technicians work with occupational health and safety specialists in conducting tests and measuring hazards to help prevent harm to workers, property, the environment, and the general public. For more information, see the profile on occupational health and safety specialists.

Duties  

Occupational health and safety technicians typically do the following:

• Inspect, test, and evaluate workplace environments, equipment, and practices to ensure they follow safety standards and government regulations
• Collect samples of potentially toxic materials for analysis by occupational health and safety specialists
• Work with occupational health and safety specialists to control and fix hazardous and potentially hazardous conditions or equipment
• Carry out and evaluate programs on workplace safety and health
• Demonstrate the correct use of safety equipment
• Investigate accidents to identify why they happened and how they might be prevented in the future

Technicians conduct tests and collect samples and measurements as part of workplace inspections. For example, they may collect and handle samples of dust, mold, gases, vapors, or other potentially hazardous materials. They conduct both routine inspections and special inspections that a specialist orders. For more information about specialists, see the profile on occupational health and safety specialists.

Technicians may examine and test machinery and equipment such as scaffolding and lifting devices to be sure that they meet appropriate safety regulations. They may check that workers are using protective gear, such as masks and hardhats, as regulations say they must.

Technicians also check that hazardous materials are stored correctly. They test and identify work areas for potential health and safety hazards.

In addition to making workers safer, technicians work with specialists to increase worker productivity by reducing the number of worker absences and equipment downtime. They save companies money by lowering insurance premiums and worker compensation payments and by preventing government fines.

Technicians' duties vary based on where they are employed. For example, a technician may test the levels of biohazard at a waste processing plant or may inspect the lighting and ventilation in an office setting. Both of these inspections are focused on maintaining the health of the workers and the environment.

The responsibilities of occupational health and safety technicians vary by industry, workplace, and types of hazards affecting employees. The following are examples of types of occupational health and safety technicians:

Environmental protection technicians evaluate and coordinate the storage and handling of hazardous waste, the cleanup of contaminated soil or water, evaluation of air pollution, or other activities that affect the environment.

Health physics technicians work in places that use radiation and radioactive material. Their goal is to protect people and the environment from hazardous radiation exposure.

Industrial hygiene technicians examine the workplace for health hazards, such as exposure to lead, asbestos, pesticides, or contagious diseases.

Mine examiners inspect mines for proper air flow and health hazards such as the buildup of methane or other harmful gases.

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.

Forensic science technicians help investigate crimes by collecting and analyzing physical evidence. Most technicians specialize in either crime scene investigation or laboratory analysis.

At crime scenes, forensic science technicians, also known as crime scene investigators, typically do the following:

• Walk through the scene to determine what and how evidence should be collected
• Take photographs of the crime scene and evidence
• Make sketches of the crime scene
• Keep written notes of their observations and findings, such as the location and position of evidence as it is found
• Collect all relevant physical evidence, including weapons, fingerprints, and bodily fluids
• Catalog and preserve evidence before transferring it to a crime lab

Crime scene investigators may use tweezers, black lights, and specialized kits to identify and collect evidence. In addition to processing crime scenes, they may also attend autopsies.

In laboratories, forensic science technicians typically do the following:

• Identify and classify crime scene evidence through scientific analysis
• Explore possible links between suspects and criminal activity using the results of chemical and physical analyses
• Consult with experts in related or specialized fields, such as toxicology, about the evidence and their findings
• Reconstruct crime scenes based on scientific findings

Forensic science technicians reconstruct crime scenes by carefully studying information gathered by investigators and conducting scientific tests on physical evidence. For example, lab technicians may look at photographs of blood splatter patterns and conduct ballistics tests on bullets found at the crime scene to determine the direction from which a shot was fired.

Forensic science technicians who work in laboratories use chemicals and laboratory equipment such as microscopes when analyzing evidence. They also use computer databases to examine fingerprints, DNA, and other evidence collected at crime scenes in order to match them to people and things that have already been identified. Most forensic science technicians who perform laboratory analysis specialize in a specific type of evidence analysis, such as DNA or ballistics.

All forensic science technicians prepare written reports that detail their findings and investigative methods. They must be able to explain their reports to lawyers, detectives, and other law enforcement officials. In addition, forensic science technicians may be called to testify in court about their findings and methods.

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.