ASME B16.9 Elbow

ASME B16.9 Elbow

Fittings are components or devices, which are used to connect different sections of pipes or tubes together. These elements help to adapt different sizes or change the flow characteristics by regulating different parameters. They require time and proper knowledge to be installed properly and efficiently. There are different types of fittings each having its own properties and functions. In this extract, we will be talking about an ASME B16.9 elbow and see how it affects the entire piping system.

The main function of a B16.9 elbow is to change the direction of flow in the system. These components can easily connect pipes and tubes of the same or different sizes. The ends of these items may be either butt-welded, machined, or socketed. They are available in sizes of 45, 90, and 180-degree bend to facilitate the smooth flow of water in the pipeline. In certain, cases, special bending characteristics can be used to produce custom sizes according to the flow characteristics.

Why is it used for?

These bends play a crucial role in pressure piping systems by changing the direction of flow. This diversion helps protect the integrity of the system and helps in supplying flow in other channels. It further adds pressures losses across the system caused due to friction, impact, and reacceleration within the system.


These elbows can be characterized by their length and radius, connection type, material, flow characteristics. Below is a list of a wide variety of these components available at your disposal.

  • Butt-welded- These components are produced by continuous hot pressing or forging operations. This connection directly welds the elbow to the steel pipe as it has beveled ends to help it in welding.
  • Socket-weld- In this weld, a trapezoidal area is present on the end of the weld, which enables the pipe end to be installed in the area.
  • Threaded- The items have threaded on their tubing ends which allows them to be threaded easily on the ends of the corresponding threaded pipe.
  • Reducing- These components are designed to facilitate the joining of pipes of different sizes.
  • Male and female- These items are designed to enable the fluid to possess a directional change in its tubing run. They are widely designed for instrumentation and various control systems.
  • These components can also be distinguished on the material used for their construction namely stainless steel, carbon, alloys, etc.

What is a 45 degree pipe elbow used for?

These units help change the flow characteristics by 45 degrees to create lower friction and lower pressures. They are commonly attached to cooper, plastic steel, lead items. The components are used in food, chemical, water supply, pipeline, solar equipment, and many other related industries.

What is a 90 degree bend?

These components are specially produced bends, which are designated to change the direction of fluids or gases by 90 degrees. This is generally done by cutting pipe in 2 pieces of 45 degrees each and then joining them in place.

How do you calculate a 90 degree elbow Center?

The items in 90 and 45 degrees are available in the standard pipe charts provided by ASME. However, to calculate it follow this formula
Length= Tan(Angle/2) X radius

How do you calculate the radius of an elbow pipe?

The radius of these components can be easily decoded using a simple formula.
Length= Tan(Angle/2) X radius.

What is a reducing elbow?

A reducer is a special element, which is designed to join two pipes or tubes of different sizes. They can be also utilized to curtail the fluid of fluids or gases across different systems.

Pipe bend vs elbow

The most basic difference between both these components is the difference in their radius of curvature. Bends have a radius of curvature more than twice its diameter, while the latter has the same value between one of twice the diameter of the pipe. Furthermore, bends have a larger radius and have many constraints attached to their production and fitting.

LR vs SR

  • Long radius-In this element the, item can change the direction of fluid from the centerline to the opposite face. They are the most common and preferred choice in different systems. These items are expensive and create lower pressure drops.
  • Short radius- The center of this component is equal to the radius of the nominal pipe size. They are used in low-pressure applications where there is a limited choice available. It is prone to pressure drops but is available at reasonable rates.

What is the radius size for LR elbow?

In these items, the radius is 1.5 times that of the nominal pipe diameter. For standard components, this is only one time the NPS of the pipe.

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