Fittings Explained: The Role of an Elbow

What Do Elbows Do?

Apart from serving as a pivotal joint for your arm, elbows function as industrial components that redirect the flow of piping. These attachments enable you to redirect standard threaded pipes around corners or into tight spaces without the need for a pipe bender.

Standard elbows are available in various angles, including 45°, 90°, and less commonly used 22.5° angles, and can be constructed from the same materials as regular piping. Our inventory features a diverse range of elbows and other fittings crafted from stainless steel 304 or 316.

Types Of Elbows

As shown in the figure, while the names are generally self-explanatory, there exist some nuances in elbows that merit exploration.

The 90° elbow, also known as a “90° ell” (pronounced like the letter “L”) or occasionally referred to as a “quarter bend,” derives its name from the right angle at which the flow is redirected, representing one quarter of a full 360° circle.

This type of elbow is utilized in areas necessitating a significant change in direction. However, this alteration can impact the flow rate and pressure within the pipeline. Similar to any piping system, the material under pressure encounters the elbow and seeks to maintain its original path. Upon encountering the resistance of the elbow’s surface, it is compelled to alter its course (deflected), resulting in a pressure drop.

The length inside the elbow contributes to this resistance. A quarter bend elbow designed to accommodate a confined space will induce greater pressure drop as the conveyed material must undergo a more abrupt change in direction.

Elbows with a center-to-face dimension equal to 1x the pipe size are known as “short radius” bends, facilitating a rapid change in direction.

Compared to “long radius” bends with a center-to-face length of 1.5x the pipe size, short radius bends incur higher pressure loss. The longer distance traveled within the fitting ensures a smoother transition for the material, resulting in reduced turbulence within the system.

Long radius bends are preferred when flow rates take precedence over space conservation in plumbing system design. Typically, both 45° and 22.5° ells are long radius, indicating lower pressure loss compared to 90° ells.

Elbows are available in various connection types, including threaded, weldable, socketed, and flanged options. Threaded elbows commonly feature male-x-male and female-x-female connections, while “street elbows” typically come in male-x-female configurations.

Typically, elbows have identical size connections on both ends. When one end is smaller than the other, the fitting is referred to as a “reducing elbow.” Caution is advised when using reducing elbows, as the change in pipe diameter can lead to alterations in pressure.

It is crucial to consider all these factors when selecting the appropriate elbow for your project to avoid ending up with the wrong one.