Summary While the pipeline industry works hard to achieve incident-free operations,
accidents do occur. Many pipeline operators have their 24-hour emergency phone number connected directly to the pipeline control center. In the event of a pipeline emergency, the control center can immediately initiate the shut- down process and begin to isolate the source of the leak. The control center may also have the capability to open and close manifold valves remotely and to transfer products both to and from the main pipeline at marketing and dis- tribution facilities.
The SCADA system continuously monitors the volume in the pipeline and
provides line balance reports. Most SCADA systems offer multiple computer screens so that an operator can instantly check operations and facts at any lo- cation. In addition, the SCADA system can display information graphically so that it can be more easily understood. If a change occurs, such as the open- ing or closing of a valve, the shape representing that specific valve on screen changes as well. Figure 3.15 provides an example of a pipeline control center and the use of a SCADA system.
SUMMARY
Underground pipelines are often marked by aboveground signs and markers that indicate the presence of the pipeline. The primary function of the markers is to alert those who might be working along the pipeline corridor or doing construction in close proximity to the pipeline and to provide emergency con- tact information. If there are multiple pipelines within a common pipeline right-of-way, there should be a marker for each pipeline. However, the ab- sence of a pipeline marker does not guarantee that a pipeline is not located in the vicinity. Although the color, format, and design may vary, all markers are required to provide the pipeline contents (e.g., natural gas, propane, liquid petroleum products, etc.), the pipeline operator, and an emergency telephone number.
Pipelines will be located within a pipeline right-of-way. Although there is
no universal look to a pipeline right-of-way, some identification clues will in- clude the presence of pipeline markers: a corridor that is clear of trees, build- ings, and other structures, or the presence of aboveground piping or pipeline facilities. In residential areas where there are fewer markers, meters can be a good indication of the presence of a natural gas distribution pipeline.
Pipelines can vary from 2-inches in diameter for gathering lines or small
distribution lines to 48-inches for transmission or trunk lines. Although most are underground, aboveground pipelines may also be found in many areas. They may be used for intrastate and interstate transportation, transporting products between industrial facilities, transferring raw materials and finished products within oil, chemical, and petrochemical facilities, and delivering liq- uid and gas fuels directly to the consumer.
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