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All About Pipe
Polyethylene (PE)

Metal pipe ruptures when freezing water expands. Flexible plastic pipe does not. Depending on local codes, it need only be buried deep enough below the surface to protect the pipe against accidental damage from digging or cultivation.

Couplings are not required unless the pipe is cut. Polyethylene has excellent chemical and crush resistance as well as high impact strength and flexibility. It functions in temperatures from -65° to 120°F in low-pressure applications and to 200° in non-pressure applications.

Polyethylene pipe is joined by use of nylon or brass fittings and stainless steel clamps and clamp screws.

PE is used in low-pressure water systems, such as golf-course sprinklers, for corrosive liquids and gases; as underground conduits and gas-pipe re-liners. It's also used in industrial and chemical laboratory drainage systems, and for underground gas piping.

This flexible or semi-rigid pipe's strength decreases as the temperature rises; therefore in high-pressure lines, it is for cold-water only. It has pressure ratings between 80 and 160 psi. It can be cut with a pocketknife. Any plastic pipe used to carry drinking water should have the seal of the National Sanitation Foundation.

PE pipe is used for hot water heating in concrete floors; temperatures of up to 100 degrees F are common for foot comfort. For this use, however, the best brand of virgin plastic rated at 115 degrees F should be used. Also, mixing valves for water temperature control should be installed.

Lines should also be laid in straight lines to avoid undue stress. PE pipe is available in diameters of up to 6 inches or larger; and it is joined by threads and clamps.

Perforated PE is used as a corrugated drainage pipe. Corrugated Pipe is soft, flexible polyethylene pipe sold in lengths or in coils and used for drainage tile around home foundations and for other ground drainage situations. It may either be solid or perforated to permit seepage.

See Also:

Other:
    ASTM Reference Library (material and manufacturing specifications)

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