Pipe is a tube used to transport liquids and gases from one place to another. Pipelines compare in importance with highways and railroads as a means of transporting materials useful to people. Huge pipes bring water to cities from wells, lakes, or other sources of supply. A vast network of pipes then distributes the water to homes, and to each sink, toilet, and other water fixtures in the house. A separate network of pipes carries the wastewater away from these fixtures through drains and sewer pipes (see Sewage ). Long pipelines buried in the ground transport and distribute natural gas in the same way water is distributed (see Pipeline ). Similar pipelines transport crude oil from wells to refineries.
The walls, floors, and basements of modern office buildings and hotels have a maze of pipes. The pipes carry hot and cold water for general use, steam for heating, and refrigerants for air conditioning. Chemical factories, refineries, and similar industries depend almost entirely on pipes to move their products about within the manufacturing plant. Warships often have such a maze of pipes that sailors on the ships find it difficult to move about.
Pipes also serve other purposes than to carry fluids. Pneumatic pipes transport containers carrying messages. Much of our electrical and telephone wiring runs through pipes known as conduits, which protect the wires from water and breakage.
Kinds of pipe.
Most water pipe larger than 3 inches (8 centimeters) in diameter is made of cast iron, reinforced concrete, steel, or a mixture of asbestos and cement. Smaller water pipes in buildings may be made of galvanized steel, copper, wrought iron, or a vinyl plastic called polyvinyl chloride (PVC). Gas and oil pipelines are built of steel pipe. Cast iron, glazed tile, and concrete are among the materials used for sewer pipe. High density polyethylene (HDPE) plastic is commonly used for drainage pipe. Irrigation systems may be made of lightweight aluminum or PVC pipe that can be easily moved. Atomic-power plants have stainless steel piping.
Pipe may be made in several ways, depending on the material and type of pipe desired. These ways include molding, casting, welding, and drawing or pushing the material over a sharp point to make a center hole.
History.
People made pipe of clay thousands of years ago to carry water. The Romans used lead pipe to connect their public fountains to aqueducts. American pioneers made water systems from logs with holes bored through their centers. Later, they made pipes from hoops and wooden staves in much the same way barrels are made.
