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Pipe joints; collar joint

Short answer

Pipes are joined to form a continuous watertight line. A collar joint uses a short sleeve slipped over plain pipe ends; the annular gap is sealed with cement mortar, yarn, lead, or a rubber ring. It is simple, cheap, and watertight but rigid and unsuitable for high pressure.

Why are pipe joints required? Describe the collar joint with a neat sketch.

Why pipe joints are required

Pipes come in short lengths (3–6 m) and must be joined to make a long, watertight line, and to connect fittings such as valves and bends.

Collar joint

A collar joint is used for plain-ended pipes, such as concrete, asbestos cement, or CI pipes without sockets. A short pipe-like sleeve, called a collar (with an inside diameter slightly more than the pipe), is slipped over the ends of the two pipes. The pipes are placed with a small gap in the middle, and the annular space on both sides is filled with cement mortar (1 : 1), yarn and lead or a rubber ring.

          collar
       ___________
  =====|=========|=====  pipe ends meet in the middle
       |_________|       gaps sealed with mortar,
     pipe 1  gap  pipe 2    yarn or rubber ring

It is simple, cheap and watertight, but rigid and not suited to high pressure.

✓ Answer checked by Claude Opus 5.5 (high effort)

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