90° 3R Elbow Dimensions
A 3R elbow turns on a centerline radius of three times the nominal pipe diameter, twice the sweep of a standard long radius elbow. The extra radius buys markedly lower turbulence and wear, which is why 3R shows up in abrasive and high-velocity service where a normal elbow would erode through.
Built for flow, not for space.
Doubling the bend radius smooths the velocity profile through the turn and spreads wear over a much larger area of the outside wall. In pneumatic conveying, catalyst transfer, sand-laden production, and slurry lines, that translates directly into longer runs between change-outs.
Plan the space early.
A 3R elbow needs a center-to-end of 3 × NPS, so a 6" fitting turns in 18" rather than 9". That has to be designed in, and it is rarely something you can substitute into an existing spool.
How To Read These Dimensions
A 3R elbow falls outside both dimensional standards. ASME B16.9 covers the 1.5D long radius pattern and ASME B16.28 covers the 1.0D short radius pattern; neither covers three diameters. 3R elbows are made to the manufacturer standard, with welding ends to ASME B16.25 and material to the same ASTM grades, so take the center-to-end from the table below rather than from a code book.
- O.D.
- Outside diameterOutside diameter at the welding end, matching the pipe it welds to.
- I.D.
- Inside diameterBore through the fitting, set by the wall thickness.
- T
- Wall thicknessNominal wall at the welding end, matched to the pipe schedule.
- C
- Center to endFrom the intersection of the centerlines to the welding face. On a 3R elbow it equals 3 times the nominal size, which makes the fitting long for the turn it produces.
76 sizes across 4 schedules · dimensions in inches, weights in pounds · Manufacturer standard
Schedule STD
| Nom. Pipe Size | Outside Diameter O.D. | Inside Diameter I.D. | Wall Thickness T | Center to End C | Pipe Schedule Number | Approx. Weight in Pounds Lbs. |
|---|---|---|---|---|---|---|
| ¾ | 1.05 | 0.824 | 0.113 | 2.25 | 40 | 0.30 |
| 1 | 1.32 | 1.054 | 0.133 | 3.00 | 40 | 0.80 |
| 1¼ | 1.66 | 1.380 | 0.140 | 3.75 | 40 | 1.10 |
| 1½ | 1.90 | 1.610 | 0.145 | 4.50 | 40 | 1.60 |
| 2 | 2.38 | 2.072 | 0.154 | 6.00 | 40 | 3.20 |
| 2½ | 2.88 | 2.474 | 0.203 | 7.50 | 40 | 6.40 |
| 3 | 3.50 | 3.068 | 0.216 | 9.00 | 40 | 9.60 |
| 3½ | 4.00 | 3.548 | 0.226 | 10.50 | 40 | 15.00 |
| 4 | 4.50 | 4.026 | 0.237 | 12.00 | 40 | 17.80 |
| 5 | 5.56 | 5.044 | 0.258 | 15.00 | 40 | 30.00 |
| 6 | 6.62 | 6.060 | 0.280 | 18.00 | 40 | 48.00 |
| 8 | 8.62 | 7.976 | 0.322 | 24.00 | 40 | 95.00 |
| 10 | 10.75 | 10.020 | 0.365 | 30.00 | 40 | 167.00 |
| 12 | 12.75 | 12.000 | 0.375 | 36.00 | * | 250.00 |
| 14 | 14.00 | 13.250 | 0.375 | 42.00 | 30 | 310.00 |
| 16 | 16.00 | 15.250 | 0.375 | 48.00 | 30 | 415.00 |
| 18 | 18.00 | 17.250 | 0.375 | 54.00 | * | 530.00 |
| 20 | 20.00 | 19.250 | 0.375 | 60.00 | 20 | 650.00 |
| 24 | 24.00 | 23.250 | 0.375 | 72.00 | 20 | 935.00 |
Schedule XS
| Nom. Pipe Size | Outside Diameter O.D. | Inside Diameter I.D. | Wall Thickness T | Center to End C | Pipe Schedule Number | Approx. Weight in Pounds Lbs. |
|---|---|---|---|---|---|---|
| ¾ | 1.05 | 0.742 | 0.154 | 2.25 | 80 | 0.30 |
| 1 | 1.32 | 0.962 | 0.179 | 3.00 | 80 | 1.58 |
| 1¼ | 1.66 | 1.278 | 0.191 | 3.75 | 80 | 2.40 |
| 1½ | 1.90 | 1.500 | 0.200 | 4.50 | 80 | 4.20 |
| 2 | 2.38 | 1.944 | 0.218 | 6.00 | 80 | 7.60 |
| 2½ | 2.88 | 2.328 | 0.276 | 7.50 | 80 | 12.60 |
| 3 | 3.50 | 2.900 | 0.300 | 9.00 | 80 | 17.20 |
| 3½ | 4.00 | 3.364 | 0.318 | 10.50 | 80 | 22.00 |
| 4 | 4.50 | 3.826 | 0.337 | 12.00 | 80 | 25.00 |
| 5 | 5.56 | 4.810 | 0.375 | 15.00 | 80 | 45.00 |
| 6 | 6.62 | 5.756 | 0.432 | 18.00 | 80 | 70.00 |
| 8 | 8.62 | 7.620 | 0.500 | 24.00 | 80 | 145.00 |
| 10 | 10.75 | 9.750 | 0.500 | 30.00 | 60 | 225.00 |
| 12 | 12.75 | 11.750 | 0.500 | 36.00 | * | 320.00 |
| 14 | 14.00 | 13.000 | 0.500 | 42.00 | * | 405.00 |
| 16 | 16.00 | 15.000 | 0.500 | 48.00 | 40 | 540.00 |
| 18 | 18.00 | 17.000 | 0.500 | 54.00 | * | 700.00 |
| 20 | 20.00 | 19.000 | 0.500 | 60.00 | 30 | 845.00 |
| 24 | 24.00 | 23.000 | 0.500 | 72.00 | * | 1210.00 |
Schedule 40
| Nom. Pipe Size | Outside Diameter O.D. | Inside Diameter I.D. | Wall Thickness T | Center to End C | Pipe Schedule Number | Approx. Weight in Pounds Lbs. |
|---|---|---|---|---|---|---|
| ¾ | 1.05 | 0.824 | 0.113 | 2.25 | 40 | 0.30 |
| 1 | 1.32 | 1.054 | 0.133 | 3.00 | 40 | 0.80 |
| 1¼ | 1.66 | 1.380 | 0.140 | 3.75 | 40 | 1.10 |
| 1½ | 1.90 | 1.610 | 0.145 | 4.50 | 40 | 1.60 |
| 2 | 2.38 | 2.072 | 0.154 | 6.00 | 40 | 3.20 |
| 2½ | 2.88 | 2.474 | 0.203 | 7.50 | 40 | 6.40 |
| 3 | 3.50 | 3.068 | 0.216 | 9.00 | 40 | 9.60 |
| 3½ | 4.00 | 3.548 | 0.226 | 10.50 | 40 | 15.00 |
| 4 | 4.50 | 4.026 | 0.237 | 12.00 | 40 | 17.80 |
| 5 | 5.56 | 5.044 | 0.258 | 15.00 | 40 | 30.00 |
| 6 | 6.62 | 6.060 | 0.280 | 18.00 | 40 | 48.00 |
| 8 | 8.62 | 7.976 | 0.322 | 24.00 | 40 | 95.00 |
| 10 | 10.75 | 10.020 | 0.365 | 30.00 | 40 | 167.00 |
| 12 | 12.75 | 11.938 | 0.406 | 36.00 | 40 | 205.00 |
| 14 | 14.00 | 13.124 | 0.438 | 42.00 | 40 | 305.00 |
| 16 | 16.00 | 15.000 | 0.500 | 48.00 | 40 | 540.00 |
| 18 | 18.00 | 16.876 | 0.562 | 54.00 | 40 | 740.00 |
| 20 | 20.00 | 18.812 | 0.594 | 60.00 | 40 | 950.00 |
| 24 | 24.00 | 22.624 | 0.688 | 72.00 | 40 | 1400.00 |
Schedule 80
| Nom. Pipe Size | Outside Diameter O.D. | Inside Diameter I.D. | Wall Thickness T | Center to End C | Pipe Schedule Number | Approx. Weight in Pounds Lbs. |
|---|---|---|---|---|---|---|
| ¾ | 1.05 | 0.742 | 0.154 | 2.25 | 80 | 0.30 |
| 1 | 1.32 | 0.962 | 0.179 | 3.00 | 80 | 1.58 |
| 1¼ | 1.66 | 1.278 | 0.191 | 3.75 | 80 | 2.40 |
| 1½ | 1.90 | 1.500 | 0.200 | 4.50 | 80 | 4.20 |
| 2 | 2.38 | 1.944 | 0.218 | 6.00 | 80 | 7.60 |
| 2½ | 2.88 | 2.328 | 0.276 | 7.50 | 80 | 12.60 |
| 3 | 3.50 | 2.900 | 0.300 | 9.00 | 80 | 17.20 |
| 3½ | 4.00 | 3.364 | 0.318 | 10.50 | 80 | 22.00 |
| 4 | 4.50 | 3.826 | 0.337 | 12.00 | 80 | 25.00 |
| 5 | 5.56 | 4.810 | 0.375 | 15.00 | 80 | 45.00 |
| 6 | 6.62 | 5.756 | 0.432 | 18.00 | 80 | 70.00 |
| 8 | 8.62 | 7.620 | 0.500 | 24.00 | 80 | 145.00 |
| 10 | 10.75 | 9.562 | 0.594 | 30.00 | 80 | 200.00 |
| 12 | 12.75 | 11.374 | 0.688 | 36.00 | 80 | 320.00 |
| 14 | 14.00 | 12.500 | 0.750 | 42.00 | 80 | 600.00 |
| 16 | 16.00 | 14.312 | 0.844 | 48.00 | 80 | 810.00 |
| 18 | 18.00 | 16.124 | 0.938 | 54.00 | 80 | 1020.00 |
| 20 | 20.00 | 17.938 | 1.031 | 60.00 | 80 | 1400.00 |
| 24 | 24.00 | 21.562 | 1.219 | 72.00 | 80 | 1800.00 |
Materials We Supply
90° 3R Elbow to Manufacturer standard in the grades below. Tell us the service and we will confirm the right one.
| Material | Specification | Typical Service |
|---|---|---|
| Carbon Steel | ASTM A234 WPB / WPC | General process, steam, oil and gas gathering and utility lines |
| Low-Temp Carbon Steel | ASTM A420 WPL6 | Cold service to −50°F; LNG and northern pipeline work |
| Chrome-Moly Alloy | ASTM A234 WP11 / WP22 / WP91 | Elevated temperature; refinery heaters, power plant steam |
| Stainless Steel | ASTM A403 WP304/304L, WP316/316L | Corrosive service, chemical, food and beverage, water treatment |
| Duplex & Super Duplex | ASTM A815 UNS S31803 / S32750 | Chloride and seawater service, offshore, desalination |
Common Questions
What does 3R mean on an elbow?
The centerline bend radius equals three times the nominal pipe diameter. A standard long radius elbow is 1.5D and a short radius elbow is 1.0D, so 3R is the widest of the three common sweeps.
Why pay for a 3R elbow?
Erosion and pressure drop. The wider sweep spreads wear across more of the outside wall and reduces turbulence, so in abrasive or high-velocity service a 3R elbow can outlast a long radius elbow by a wide margin. In clean, moderate service the added cost and space usually are not justified.
Are 3R elbows covered by ASME B16.9?
No, and it is worth knowing before you write the spec. ASME B16.9 covers the 1.5D long radius pattern and ASME B16.28 covers the 1.0D short radius pattern; neither one covers a three-diameter radius. A 3R elbow is a manufacturer-standard fitting with ASME B16.25 welding ends and the same ASTM material grades, so confirm the center-to-end against the table above before you fabricate.
