Pipe Elbow Dimensions – Long & Short Radius Elbow Dimensions in mm

Pipe elbow dimensions & sizes are mainly determined by parameters such as nominal diameter (DN/NPS), bending radius (R), bending angle, wall thickness (Sch) and pressure level (Class/PN). The sizes of elbow fittings of different standards and types vary.

1. Main size parameters

Nominal diameter (DN): indicates the diameter size of the elbow (such as DN15, DN20, DN25, DN50, DN100), which needs to match the pipe.

American Standard (NPS, inches): 1/2", 3/4", 1", 1.5", 2", 3", 4", 6", 8", 10", 12", etc.

Bending radius (R): divided into short radius (SR) and long radius (LR)
- SR: R = 1.0 × DN (such as DN100 elbow R = 100mm)     Application: low pressure drop, high flow system (such as chemical, petroleum pipeline).

- LR: R = 1.5 × DN (such as DN100 elbow R = 150mm)     Application: space-constrained installation scenarios (such as equipment interface, compact pipeline).

Bending angle: Common 45°, 90°, 180° (U-bend), special angles can be customized.
Among them, 90° elbow is the most commonly used, changing the flow direction by 90 degrees. 45° elbow eases the change of flow direction and reduces turbulence. 180° elbow is used for reverse arrangement of pipelines.

Wall thickness (Sch): Select according to the pressure level, such as Sch5, Sch10, Sch20, Sch40, Sch80, Sch160 (refer to ASME B36.10 standard).
Among them, Sch40 elbow (standard wall thickness) and Sch80 elbow (thickened) are most commonly used.

Wall thickness effect: high pressure, high temperature or corrosive media need to choose a higher Sch number.

2. Pressure level effect

Class series (American standard): such as Class150, Class300, corresponding to the dimensional tolerance under different pressures (refer to ASME B16.5).
PN series (Chinese standard): such as PN10, PN16, affecting the elbow wall thickness and flange connection size.

Pipe Elbow dimensions are covered in ASME B16.9. Refer to the table given below for the dimension of the elbow size 1/2″（21.3mm) to 48″(1220mm).

Dimensions of Pipe Elbow according to ASME B16.9:

Dimensions of Special Elbows:

Reducing elbows: The diameters of the large end (DN1) and the small end (DN2) must be marked. For example, for DN100×50, you need to check the dimension table separately.
Threaded elbows: The dimensions are based on the NPT or BSP thread standards (such as 1/2"NPT, 3/4"BSP).

Stamped elbows: Commonly used for small diameters (DN15-DN50), the dimensions may be slightly smaller than welded elbows.

Manufacturing Process of Pipe Elbow:

How to choose elbow size?

Match pipe diameter: The DN/NPS of the elbow must be consistent with the pipe.
Select wall thickness according to pressure: Sch80 or higher for high pressure.
Space limitations: Use short radius (SR) for narrow areas and long radius (LR) for smooth turning.
Medium characteristics: Corrosive media require increased wall thickness or stainless steel (such as 304/316).

How to obtain specific dimensions?

Check standard manuals: such as ASME B16.9, GB/T 12459.
Manufacturer's catalog: Different manufacturers may provide slightly different size tables.
Online tools: Use pipe size calculator (e.g. PVC elbows and metal elbows have different sizes).

Conclusion:

The actual selection of pipe elbows needs to be determined in combination with the pipe material (carbon steel, stainless steel, PVC, etc.), medium pressure/temperature and installation space!

Read more: Material Selection and Application of Pipe Elbows or ASTM A403 WP316 Stainless Steel Butt-weld Elbow