For structural tubing, see hollow structural section

Tubing refers to a flexible hose or pipe used in plumbing, irrigation, and other industries. Tubing may be made of polyvinyl chloride (PVC), polyethylene (PE), copper, or other material. Tubing is usually supplied in rolls compared to rigid pipe which is sold in straight lengths called joints or sticks. Tubing is usually measured by its outside diameter, while pipe is usually measured by its inside diameter.

Metal tubing differs from metal pipe in the way it is dimensioned. Tubing is specified by OD and wall thickness, whereas pipe is specified by a non-dimensional nominal pipe size (NPS) and a schedule (SCH). Metal tubing generally has much thinner wall than pipe and can be bent, although both of these depend on the specific application.

Manufacture

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Three methods exist for tubing manufacture: seamless, as-welded, and drawng-over-mandrel (DOM).

Standards

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Many standards exist for tube manufacture. Some of the most common ones are as follows:

• ASTM A213 seamless stainless steel pressure tubing
• ASTM A269 welded stainless steel pressure tubing
• ASTM A270 seamless and welded stainless steel sanitary tubing
• ASTM A511 seamless stainless steel mechanical tubing
• ASTM A554 welded stainless steel mechanical tubing

ASTM material specifications generally cover a variety of grades or types that indicate a specific material composition. Some of the most commonly used are:

• TP 304
• TP 316
• MT 304

Plumbing