Introduction to Pipe Fittings

Fittings are used in pipe and plumbing systems to connect straight pipe or
tubing sections, to adapt to different sizes or shapes, to branch or re-direct the
piping system and if necessary to provide a jointing method if 2 dissimilar
piping materials are used in the one system. Fittings for pipe and tubing are
most often made from the same base material as the pipe or tubing being
connected, e.g., stainless steel, steel, copper or plastic. However, any material
that is allowed by code may be used, but must be compatible with the other
materials in the system, the fluids being transported, and the temperatures and
pressures inside and outside of the system. For example, brass-bodied fittings
are common in otherwise copper piping and plumbing systems. The
photographs below show some common fittings that are used in piping

Identifying Basic Pipe Fittings

Fittings for piping systems can be expensive and require a proportionally large
labour element to install, therefore correct selection and use is of vital
importance to a well installed piping system. Every type of piping material has
a range of fittings that can be used with it and some piping materials can have
multiple different ranges of fittings that can be used. For example copper
piping systems can be installed by bending the pipe and therefore using no
elbows, using soldered copper fittings or compression brass fittings depending
on the type of service being transferred in the copper pipe. Fittings are
available with ends to match the piping installation therefore the following
information will not differentiate between welded, threaded or compression
but will concentrate on the orientation and the use of the fitting. The most
common type of pipe fittings are:

* Elbow
* Tee
* Cross
* Reducer
* Cap
* Union


A pipe fitting installed between two lengths of pipe or tube allowing a change
of direction, usually 90° or 45°. The ends may be machined for butt welding,
threaded (usually female), or socketed, etc. When the two ends differ in size, it
is called a reducing or reducer elbow. Most elbows are available in short radius
or long radius of types. The short radius elbows have a center to end distance
equal to the nominal diameter, while the long radius is 1.5 times the nominal
diameter. Elbows used on powder transfer systems have a much longer radius
(radius of bend can be 10 times the nominal diameter of the pipe) to ensure
smooth flow, reduce wear to both product and piping and to reduce the
chance of getting blockages.


A tee is used to either combine or split a fluid flow. Most common are equal
tees which have the same body and branch diameter but there is also a wide
range of reducing tees where either the branch or the body is a different
diameter relative to each other.

A swept tee is where the branch enters the body at an arc and is used to
minimize the frictional losses and promote flow in the system. A wye tee is
where the branch is stabbed into the body at an angle and is usually used where
the branch is a smaller diameter than the main pipe.


A cross has one inlet and three outlets, or vice versa and like tees come in
equal and reducing forms. A cross is more expensive than two tees but has the
advantage of reduced space and requires less labour to install.


Reducers are used to join 2 different pipe sizes together. They can be either
concentric or eccentric which refers to the relative position of the center lines
of the outlet and inlet. Special attention must be given when using reducers in
a horizontal orientation as the slope will prevent free draining of a system if
not installed correctly.


A type of pipe fitting which is liquid or gas tight, and is used to cover the end
of a pipe. A cap has a similar function to a plug. For screwed systems the cap
would have female threads where a plug would have male threads. (adsbygoogle = window.adsbygoogle || []).push({});

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