More about Pipe

Click here to find Pipe Manufacturers | Discuss Pipe & Other Topics

Pipes are conduits used for the transport of various liquids and gases, including air, water and oil. They are manufactured in a vast assortment of materials, including aluminum, brass, copper, iron, PVC, polyethylene and stainless steel. The correct choice of pipe material is dependant upon the application, as certain materials are unsuited to carrying corrosive fluids, while others may not be strong enough to withstand the pressures involved in the operation.

Piping is used extensively in plumbing, food processing and waste control, as well as a variety of industrial applications. Typically, pipes used in these processes accord with standard pipe measurements, Nominal Pipe Size and schedule, which do not directly represent inner or outer diameter measurements. Although manufacturers and suppliers list pipe size by an inch-measurement, this number differs from the thread fittings’ ID or OD. In other words, a ½-inch Nominal Pipe Size may correspond to a ¾-inch thread fitting diameter, not a ½-inch diameter. The schedule, coupled with the NPS, will determine the proper diameter rating and wall thickness. Pipe length is much less difficult to specify, but it can be difficult to properly size, especially in offset pipes.

In addition to the basic pipe measurements of length, thread diameter and wall thickness, there are a number of other attributes to consider for any piping choice. These include pressure and temperature capacity, as well as the resistance properties of the alloy or synthetic in question. Pressure ratings are specifically regulated by the American Society of Mechanical Engineers, which has an extensive system of standard ASME rankings. Pipe design is also a primary factor in choice, and pipes can be threaded or unthreaded (measured by OD), with inner or outer threads. Although pipes can be designed in curved or non-standard shapes, the majority of directional flow changes are left to pipe fittings, which attach to existing pipes. Fitting shapes include elbows, crosses and tees.

Pipe manufacturers use a number of metal fabrication processes to create pipes, such as rolling, welding and rotary piercing. For PVC, polyethylene and other synthetics, extrusion is the most common method of manufacture. A variety of finishing processes are also employed, including plating and lining.