Every 90° butt-weld elbow inquiry needs one detail that buyers sometimes omit: LR or SR? The two look similar in a photo but are different products with different dimensions, prices and use cases.
The Definition
| Long Radius (LR) | Short Radius (SR) | |
|---|---|---|
| Bend radius | 1.5 × nominal pipe size | 1 × nominal pipe size |
| Center-to-face, 6” elbow | 229 mm | 152 mm |
| Flow resistance | Lower | Higher |
| Space required | More | Less |
| Price & weight | Slightly higher | Slightly lower |
| Availability | Standard, always stocked | Less common |
Both are covered by ASME B16.9 and share the same wall thickness schedule as the matching pipe.
When to Use Which
Long radius is the default. The gentler curve reduces turbulence, pressure drop and erosion, which is why LR elbows are specified in the vast majority of oil & gas, water and process piping. If a drawing just says “90° elbow” without specifying, it almost always means LR — but confirm in writing before production.
Short radius is a space-saver. SR elbows fit tight plant layouts where an LR elbow physically will not fit. The trade-off is higher pressure loss and faster erosion at the bend, so avoid SR in abrasive or high-velocity service.
Beyond both: 3D and 5D bends. Where pressure drop matters even more — long pipelines, pigging operations — induction bends with a radius of 3 or 5 times the pipe diameter replace standard elbows.
How to Specify in Your Inquiry
A complete elbow specification looks like this:
90° LR Elbow, 6” SCH40, ASTM A234 WPB, seamless, ASME B16.9, beveled ends, 500 pcs
That single line covers angle, radius, size, wall thickness, material grade, manufacturing type, standard and ends — everything a factory needs to quote accurately the first time. See our dimension charts for LR and SR center-to-face values from 1” to 24”.
Need pipe fittings from China?Send us your specification list — we reply with a detailed quotation within 24 hours.
Request a Quote