The cross-section of most pipes is round, though square, hexagonal, octagonal or otherwise shaped pipes may also be found. Copper pipes in particular are well suited to conditions which may require additional shaping and forming as the metal is soft and malleable.
While the formability and ductility of copper make copper piping popular, other properties such as chemical resistance, low oxidation rates, electrical and heat conductivity, strength, as well as resistance to extreme temperatures at either end of the spectrum are also important. Copper pipes are also non-sparking making them highly sought after in hazardous applications within the petrochemical, chemical, automotive, architectural, building, construction, electronics, food processing, marine, aerospace, wiring, power generation, waste treatment, lighting and telecommunications industries.
In these and other industrial, commercial and residential applications copper pipes are most commonly implicated in plumbing or heating and cooling systems though other uses abound. To suit these many applications, light weight copper pipes are available in one of two types: flexible and rigid. Rigid copper pipe is commonly used for a neater initial installation, while the ability to maneuver around pre-existing obstacles makes flexible copper the preferred choice for repairs and updates.
In addition to the distinction between flexible and rigid piping, several considerations should be taken into account with regards to the final use of copper pipes. Copper suppliers can help to discern the best pipe for an application, but in general buyers should consider the purity of copper alloy pipes, weight, tempering, finishing treatments, fittings and dimensions such as thickness, length, outer diameter, inner diameter and the like. The manufacturing method of a given pipe may also have an impact on its applicability and functionality in some environments.
The two most common techniques for pipe fabrication are plate rolling and extrusion. The latter involves heating stock copper forms, such as billets, before pushing them through a specially created die or series of progressively smaller dies. This results in the production of seamless tubes with uniform wall thickness and a smooth surface. If a smooth finish is not crucial, plate rolling may instead be used. In this process the stock form is a sheet or plate, depending upon the desired thickness.
The flat metal is rolled and then welded at the seam. After this initial step copper pipes may undergo any of several secondary operations such as bending, spooling, flanging, swaging, cutting, and threading to name a few. Copper pipes in particular are well suited to secondary processes due to their soft malleable quality. Copper scrap from any of these processes can easily be recycled back into production.