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6.5: Check Your Understanding

  • Page ID
    15590
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    Take a few minutes to answer the questions below to check your understanding of the lesson content.

    Q1: Societal Benefits and Costs

    There are societal benefits and costs associated with natural gas pipelines. What are some of these?

    Answer

    You should consider that natural gas pipelines are a safe and cost effective transportation method to supply the 63% of American homes that use natural gas, support the 25% of US electrical generation, and its use as feedstock for pharmaceuticals, plastics, resins, and food products such as grain and oilseed milling. In contrast, natural gas pipelines have environmental impacts during construction and operation, can have negative impacts to property and land values including view sheds and landscape, and can have safety and human health concerns.

    Q2: Steps Involved in Construction

    Installing a pipeline is much like an assembly line process, with sections of the pipeline being completed in stages. Describe, in order, the steps involved in pipeline construction.

    Answer
    1. Planning route, surveying
    2. Permitting
    3. Acquiring the right of way (ROW)
    4. ROW is cleared
    5. Topsoil removed, trench dug
    6. "Stringing Pipe"
    7. Pipe is welded and contoured
    8. Pipe is lowered into trench
    9. Pipe is placed underground and site is restored

    Q3: Easements and Terminology

    Acquiring a right of way (ROW), also known as an easement, is a necessary step in the construction of a pipeline. Describe what rights a ROW provides to the landowner and the pipeline company.

    Answer

    A pipeline right-of-way is a strip of land over and around natural gas pipelines where some of the property owner’s legal rights have been granted to a pipeline operator. A right-of-way agreement between the pipeline company and the property owner is also called an easement and is usually filed in the county Register and Recorders Office with property deeds. Rights-of-way and easements provide a permanent, limited interest in the land that enables the pipeline company to install, operate, test, inspect, alter, repair, maintain, replace, and protect one or more pipelines within the designated easement. These easements can be both permanent and temporary, with temporary easements granting the pipeline company additional space for construction.

    Q4: Safety and Failures

    A. To ensure the efficient and safe operation of natural gas pipelines, pipeline operators routinely inspect their pipelines. What mechanisms do pipeline companies use to help ensure safety?

    Answer
    • Pigs are robotic devices that are propelled down pipelines to evaluate the interior of the pipe.
    • Aerial patrols: Planes are used to ensure that no construction activities are taking place too close to the route of the pipeline, particularly in residential areas.
    • Leak detection: Natural gas detecting equipment is periodically used by pipeline personnel on the surface to check for leaks. This is especially important in areas where the natural gas is not odorized.
    • Gas sampling: Routine sampling of the natural gas in pipelines ensures its quality and may also indicate corrosion of the interior of the pipeline or the influx of contaminants.
    • Preventive maintenance: This involves the testing of valves and the removal of surface impediments to pipeline inspection.
    • Emergency response: Most pipeline companies have emergency response teams that train for the possibility of a wide range of potential accidents and emergencies.

    B. PHMSA is responsible for maintaining industry inspection standards and incident investigations of pipeline failures. It tracks the causes for distribution lines and transmission lines. The #1 cause for each type of line is the same. Identify this primary cause as well as other causes of pipeline breakdown.

    Answer
    • Excavation damage is the #1 cause of pipeline failure for distribution and transmission lines. Other failure causes include: material/weld/equipment failure, incorrect operation , corrosion, natural force damage, and other outside force damage.
    • Damage prevention guide for excavators, farmers, homeowners
    • Upstream, midstream, downstream

    6.5: Check Your Understanding is shared under a CC BY-NC-SA 4.0 license and was authored, remixed, and/or curated by Marcellus Matters via source content that was edited to conform to the style and standards of the LibreTexts platform; a detailed edit history is available upon request.

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