Water pipe

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This article is about pipes used to carry water in plumbing. For the smoking device known as a water pipe, see Hookah or bong. For other uses of the word, see pipe.

A system of copper water tubes used in a radiator heating system.

Water pipes are pipes or tubes, frequently made of polyvinyl chloride, Polyethylene or copper, that carry pressurized and treated fresh water to buildings (as part of a municipal water system), as well as inside the building.

An original Roman lead pipe with a folded seam, at the Roman Baths in Bath, UK.

For many centuries, lead was the favored material for water pipes, due to its malleability (this use was so common that the word "plumbing" derives from the Latin word for lead). This was a source of lead related health problems in the years before the health hazards of ingesting lead were fully understood; among these were stillbirth and high rates of infant mortality. Lead water pipes were still in common use in the early 20th century and remain in many households. Lead-tin alloy solder was commonly used to join copper pipes, but modern practice uses pure tin to join copper in order to eliminate lead hazards.

Wooden pipes were used during the colonial era in Boston. The pipes were hollowed out logs. These logs were tapered at the end with a small hole in which the water would pass through. The multiple pipes were then sealed together with hot animal fat.

Iron pipe was long a lower cost alternative to copper, before the advent of durable plastic materials but special non-conductive fittings must be used where transistions are to be made to other metalic pipes, except for terminal fittings, in order to avoid corrosion owing to electochemical reactions between dissimilar metals (see galvanic cell).

Bronze fittings and short pipe segments are commonly used in combination with various materials.

[edit] Pipe v Tube

Pipe is usually rigid and is supplied in straight lengths called joints or sticks compared to tubing, which is usually flexible and supplied in rolls. Water pipe is measured by its Nominal Pipe Size (NPS). Pipe in other industries is also measured by its NPS, while tubing is measured by its outside diameter.