What Is FIP in Plumbing?

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What Is FIP in Plumbing?
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An FIP is a "female iron pipe," or one in which the threads are on the inside.

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Defintion

Simply, FIP is pipe that is threaded on the inside. As a female, it accepts the male pipe, which is threaded on the outside. The male end is twisted inside the female until it is snug. In order to keep a proper seal, Teflon tape is needed around the male threads.

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Function

Threaded pipes provide an effective seal for pipes transporting liquids, gases, steam, and hydraulic fluid. They are used for everything from shut-off valves to water heaters.

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Types

Aside from iron pipes, female threads are used in copper, steel, brass, PVC, nylon and bronze pipes. But not all of the pipes are interchangeable. Before using a particular type, check to see if it will be compatible with what will pass through it.

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Size

The most common FIP sizes are 1/8, 1/4, 1/2, 3/4, 1, 1 1/4, and 2 inch, with smaller sizes used mainly for compressed air. You rarely will find larger sizes, and hardly ever in a residence.

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Threading Your Own

Pipe Threader. From www.rigid.com
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Unthreaded pipes can be threaded with a pipe threader. Use cutting oil and place the die inside the pipe for a female thread, then turn. Be careful, though, as pipe threads are usually sharp.

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