180° Long Radius Return Bend Dimensions

A return bend reverses the direction of flow in one fitting. The long radius pattern turns on a 1.5D centerline radius, giving the gentler flow path of two long radius elbows without the weld between them.

Where returns are used.

Heater coils, heat exchanger banks, tank farm hairpins, and any serpentine run that has to fold back on itself. Using a single return bend instead of two welded elbows removes a joint from a service that is often hot, cyclic, and awkward to inspect.

Center-to-center and back-to-face.

V is the distance between the two run centerlines and W is the back-to-face dimension. Both are needed to lay out coil spacing, so take them from the table rather than deriving them from elbow dimensions.

113 sizes across 6 schedules · dimensions in inches, weights in pounds · ASME B16.9

Schedule STD

Nom. Pipe Size	Outside Diameter O.D.	Inside Diameter I.D.	Wall Thickness T	Center to Center V	Back to Face W	Pipe Schedule Number	Approx. Weight in Pounds Lbs.
½	0.84	0.622	0.109	3.00	1.88	40	0.32
¾	1.05	0.824	0.113	3.00	2.00	40	0.34
1	1.32	1.049	0.133	3.00	2.19	40	0.74
1¼	1.66	1.380	0.140	3.75	2.75	40	1.10
1½	1.90	1.610	0.145	4.50	3.25	40	1.60
2	2.38	2.067	0.154	6.00	4.19	40	3.20
2½	2.88	2.469	0.203	7.50	5.19	40	6.10
3	3.50	3.068	0.216	9.00	6.25	40	9.40
3½	4.00	3.548	0.226	10.50	7.25	40	12.80
4	4.50	4.026	0.237	12.00	8.25	40	17.50
5	5.56	5.047	0.258	15.00	10.31	40	29.30
6	6.62	6.065	0.280	18.00	12.31	40	47.00
8	8.62	7.981	0.322	24.00	16.31	40	87.00
10	10.75	10.020	0.365	30.00	20.38	40	164.00
12	12.75	12.000	0.375	36.00	24.38	*	237.00
14	14.00	13.250	0.375	42.00	28.00	30	311.00
16	16.00	15.250	0.375	48.00	32.00	30	408.00
18	18.00	17.250	0.375	54.00	36.00	*	514.00
20	20.00	19.250	0.375	60.00	40.00	20	636.00
24	24.00	23.250	0.375	72.00	48.00	20	908.00

Schedule XS

Nom. Pipe Size	Outside Diameter O.D.	Inside Diameter I.D.	Wall Thickness T	Center to Center V	Back to Face W	Pipe Schedule Number	Approx. Weight in Pounds Lbs.
½	0.84	0.546	0.147	3.00	1.88	80	0.45
¾	1.05	0.742	0.154	3.00	2.00	80	0.52
1	1.32	0.957	0.179	3.00	2.19	80	0.97
1¼	1.66	1.278	0.191	3.75	2.75	80	1.60
1½	1.90	1.500	0.200	4.50	3.25	80	2.20
2	2.38	1.939	0.218	6.00	4.19	80	4.10
2½	2.88	2.323	0.276	7.50	5.19	80	7.70
3	3.50	2.900	0.300	9.00	6.25	80	12.40
3½	4.00	3.364	0.318	10.50	7.25	80	17.10
4	4.50	3.826	0.337	12.00	8.25	80	24.10
5	5.56	4.813	0.375	15.00	10.31	80	41.70
6	6.62	5.761	0.432	18.00	12.31	80	68.20
8	8.62	7.625	0.500	24.00	16.31	80	140.00
10	10.75	9.750	0.500	30.00	20.38	60	217.00
12	12.75	11.750	0.500	36.00	24.38	*	311.00
14	14.00	13.000	0.500	42.00	28.00	*	400.00
16	16.00	15.000	0.500	48.00	32.00	40	540.00
18	18.00	17.000	0.500	54.00	36.00	*	686.00
20	20.00	19.000	0.500	60.00	40.00	30	840.00
24	24.00	23.000	0.500	72.00	48.00	*	1210.00

Schedule 40

Nom. Pipe Size	Outside Diameter O.D.	Inside Diameter I.D.	Wall Thickness T	Center to Center V	Back to Face W	Pipe Schedule Number	Approx. Weight in Pounds Lbs.
½	0.84	0.622	0.109	3.00	1.88	40	0.32
¾	1.05	0.824	0.113	3.00	2.00	40	0.34
1	1.32	1.054	0.133	3.00	2.19	40	0.74
1¼	1.66	1.380	0.140	3.75	2.75	40	1.10
1½	1.90	1.610	0.145	4.50	3.25	40	1.60
2	2.38	2.072	0.154	6.00	4.19	40	3.20
2½	2.88	2.474	0.203	7.50	5.19	40	6.10
3	3.50	3.068	0.216	9.00	6.25	40	9.40
3½	4.00	3.548	0.226	10.50	7.25	40	12.80
4	4.50	4.026	0.237	12.00	8.25	40	17.50
5	5.56	5.044	0.258	15.00	10.31	40	29.30
6	6.62	6.060	0.280	18.00	12.31	40	47.00
8	8.62	7.976	0.322	24.00	16.31	40	87.00
10	10.75	10.020	0.365	30.00	20.38	40	164.00
12	12.75	11.938	0.406	36.00	24.38	40	240.00
14	14.00	13.124	0.438	42.00	28.00	40	315.00
16	16.00	15.000	0.500	48.00	32.00	40	410.00
18	18.00	16.876	0.562	54.00	36.00	40	520.00
20	20.00	18.812	0.594	60.00	40.00	40	640.00
24	24.00	22.624	0.688	72.00	48.00	40	915.00

Schedule 80

Nom. Pipe Size	Outside Diameter O.D.	Inside Diameter I.D.	Wall Thickness T	Center to Center V	Back to Face W	Pipe Schedule Number	Approx. Weight in Pounds Lbs.
½	0.84	0.546	0.147	3.00	1.88	80	0.45
¾	1.05	0.742	0.154	3.00	2.00	80	0.52
1	1.32	0.962	0.179	3.00	2.19	80	0.97
1¼	1.66	1.278	0.191	3.75	2.75	80	1.60
1½	1.90	1.500	0.200	4.50	3.25	80	2.20
2	2.38	1.944	0.218	6.00	4.19	80	4.10
2½	2.88	2.328	0.276	7.50	5.19	80	7.70
3	3.50	2.900	0.300	9.00	6.25	80	12.40
3½	4.00	3.364	0.318	10.50	7.25	80	17.10
4	4.50	3.826	0.337	12.00	8.25	80	24.10
5	5.56	4.810	0.375	15.00	10.31	80	41.70
6	6.62	5.756	0.432	18.00	12.31	80	68.20
8	8.62	7.620	0.500	24.00	16.31	80	140.00
10	10.75	9.562	0.594	30.00	20.38	80	220.00
12	12.75	11.374	0.688	36.00	24.38	80	315.00
14	14.00	12.500	0.750	42.00	28.00	80	410.00
16	16.00	14.312	0.844	48.00	32.00	80	550.00
18	18.00	16.124	0.938	54.00	36.00	80	695.00
20	20.00	17.938	1.031	60.00	40.00	80	850.00
24	24.00	21.562	1.219	72.00	48.00	80	1225.00

Schedule 160

Nom. Pipe Size	Outside Diameter O.D.	Inside Diameter I.D.	Wall Thickness T	Center to Center V	Back to Face W	Pipe Schedule Number	Approx. Weight in Pounds Lbs.
½	0.84	0.464	0.188	3.00	1.88	160	0.40
¾	1.05	0.612	0.219	3.00	2.00	160	0.43
1	1.32	0.820	0.250	3.00	2.19	160	0.93
1¼	1.66	1.160	0.250	3.75	2.75	160	1.38
1½	1.90	1.338	0.281	4.50	3.25	160	2.00
2	2.38	1.692	0.344	6.00	4.19	160	4.00
2½	2.88	2.130	0.375	7.50	5.19	160	7.63
3	3.50	2.624	0.438	9.00	6.25	160	11.75
4	4.50	3.438	0.531	12.00	8.25	160	21.88
5	5.56	4.310	0.625	15.00	10.31	160	36.63
6	6.62	5.182	0.719	18.00	12.31	160	58.75
8	8.62	6.808	0.906	24.00	16.31	160	108.75
10	10.75	8.500	1.125	30.00	20.38	160	205.00
12	12.75	10.126	1.312	36.00	24.38	160	296.25
14	14.00	11.188	1.406	42.00	28.00	160	388.75
16	16.00	12.812	1.594	48.00	32.00	160	510.00
18	18.00	14.438	1.781	54.00	36.00	160	642.50
20	20.00	16.062	1.969	60.00	40.00	160	795.00
24	24.00	19.312	2.344	72.00	48.00	160	1135.00

Schedule XXS

Nom. Pipe Size	Outside Diameter O.D.	Inside Diameter I.D.	Wall Thickness T	Center to Center V	Back to Face W	Pipe Schedule Number	Approx. Weight in Pounds Lbs.
½	0.84	0.252	0.294	3.00	1.88	*	0.44
¾	1.05	0.434	0.308	3.00	2.00	*	0.47
1	1.32	0.604	0.358	3.00	2.19	*	1.02
1¼	1.66	0.896	0.382	3.75	2.75	*	1.51
1½	1.90	1.100	0.400	4.50	3.25	*	2.20
2	2.38	1.508	0.436	6.00	4.19	*	4.40
2½	2.88	1.776	0.552	7.50	5.19	*	8.39
3	3.50	2.300	0.600	9.00	6.25	*	12.93
4	4.50	3.152	0.674	12.00	8.25	*	24.06
5	5.56	4.060	0.750	15.00	10.31	*	40.29
6	6.62	4.892	0.864	18.00	12.31	*	64.63
8	8.62	6.870	0.875	24.00	16.31	*	119.63
10	10.75	8.750	1.000	30.00	20.38	140	225.50
12	12.75	10.750	1.000	36.00	24.38	120	325.88

Materials We Supply

180° Long Radius Return Bend to ASME B16.9 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 is a 180 degree return bend used for?

Reversing flow direction in a single fitting, typically in heater coils, exchanger banks, and serpentine runs. It does the job of two 90° elbows without the weld between them.

What are the V and W dimensions?

V is centerline-to-centerline between the two legs, which sets your coil spacing. W is the back-to-face dimension, from the outside of the bend to the welding face. Both are in the tables above.

Can I use two 90° elbows instead of a return bend?

Functionally yes, but it adds a weld in a location that is often hot, cyclic, and hard to inspect. Where a return bend fits the required spacing, it is the more robust choice.

Other Butt Weld Fittings

90° Long Radius Elbows 90° Short Radius Elbows 90° 3R Elbows 45° Long Radius Elbows 45° 3R Elbows 90° Reducing Elbows Straight Tees Reducing Tees Reducers (Concentric & Eccentric)Caps Lap Joint Stub Ends 180° Short Radius Return Bends