Oil Pipelines

Some of the oil pipelines constructed in the United States include the “Big Inch” and “Little Big Inch” pipelines built during World War II to counter the threat of German submarine attacks on coastal tankers; a large product pipeline from Houston, Texas, to Linden, N.J.,

built by the Colonial Pipeline Company in the 1960s to counter the strike of the maritime union; and the Trans-Alaska Pipeline built to bring crude oil from the North Slope to Prudhoe Bay for meeting the challenge posed by the Arab oil embargo of 1973.

Offshore (submarine) pipelines are needed for transporting oil and natural gas from offshore oil wells and gas wells to overland pipelines, which further transport the oil to a refi- nery or the gas to a processing plant. They are more expensive and difficult to build than overland pipelines. Offshore cons- truction usually employs a barge on which pipe sections are welded together and connected to the end of the overland pipe. As more sections are welded to the pipe end, the barge moves toward the oil or gas field, and the completed portion of the pipe is continuously lowered into the sea behind the barge. Construction progresses until the barge has reached the field and the pipe is connected to the oil or gas well. In deep seas with large waves, ships instead of barges are used to lay the pipe. The most notable offshore oil pipeline is one linking the British North Sea oil fields to the Shetland Islands.

Water and Sewer Lines

Pipelines are used universally to bring water from treat- ment plants to individual households or buildings. They form an underground network of pipe beneath cities and streets. Water pipelines are usually laid a few feet (one metre or more) underground, depending on the frost line of the location and the need for protection against accidental damage by digging or construction activities.

In modern water engineering, while copper tubing is com- monly used for indoor plumbing, large-diameter outdoor high- pressure water mains (trunk lines) may use steel, ductile-iron, or concrete pressure pipes. Smaller-diameter lines (branch lines) may use steel, ductile-iron, or PVC pipes. When metal pipes are used to carry drinking water, the interior of the pipe often has a plastic or cement lining to prevent rusting, which may lead to a deterioration in water quality. The exteriors of metal pipes also are coated with an asphalt product and

wrapped with special tape to reduce corrosion due to contact with certain soils. In addition, direct-current electrodes are often placed along steel pipelines in what is called cathode protection.

Domestic sewage normally contains 98 percent water and 2 percent solids. The sewage transported by pipeline (sewers) is normally somewhat corrosive, but it is under low pressure. Depending on the pressure in the pipe and other conditions, sewer pipes are made of concrete, PVC, cast iron, or clay. PVC is especially popular for sizes less than 12 inches (30 centimeters) in diameter

Water Pipelines

Two millennia ago the ancient Romans made use of large aqueducts to transport water from higher altitudes by building the aqueducts in graduated segments that allowed gravity to simply push the rushing water along until it reached its in- tended destination. Hundreds of these were built throughout Europe and elsewhere, and along with flour mills were considered the lifeline of the Roman Empire. The ancient Chinese also made use of channels and pipe systems for public works. The infamous Han Dynasty court eunuch Zhang Rang (d. 189 AD) once ordered the engineer Bi Lan to construct a series of square-pallet chain pumps outside the capital city of Luoyang. These chain pumps serviced the imperial palaces and living quarters of the capital city as the water lifted by the chain pumps were brought in by a stoneware pipe system.

Pipelines are useful for transporting water for drinking or irrigation over long distances when it needs to move over hills, or where canals or channels are poor choices due to considé- rations of evaporation, pollution, or environmental impact. The 530 km (360 mile) Goldfields Water Supply Scheme in Western Australia using 760 mm (30 inch) pipe and completed in 1903 was the largest water supply scheme of its time.

Examples of significant water pipelines in South Australia are the Morgan-Whyalla (completed 1944) and Mannum- Adelaide (completed 1955) pipelines.

There are two Los Angeles, California aqueducts, the First Los Angeles Aqueduct (completed 1913) and the Second Los Angeles Aqueduct (completed 1970) which also include extensive use of pipelines.