Dimensional Tolerances for 180º Return Bends

Nominal Pipe Size	½ to 2½	3 to 3½	4	5 to 8	10 to 18	20 to 24	26 to 30	37 to 48
Outside Diameter at Bevel, D [Notes (1), and (2)]	+0.06 - 0.03	±0.06	±0.06	+0.09 - 0.06	+0.16 - 0.12	+0.25 - 0.19	+0.25 - 0.19	+0.25 - 0.19
Inside Diameter at End [Notes (1), (3), and (4)]	± 0.03	± 0.06	± 0.06	± 0.06	± 0.12	± 0.19	± 0.19	± 0.19
Wall Thickness, t [Note (3)]	Not Less Than 87.5% of Nominal Thickness
Center-to-Center Dimension, O	± 0.25	± 0.25	± 0.25	± 0.25	± 0.38	± 0.38	...	...
Back-to-Face Dimension, K	± 0.25	± 0.25	± 0.25	± 0.25	± 0.25	± 0.25	...	...
Alignment of Ends, U	± 0.03	± 0.03	± 0.03	± 0.03	± 0.06	± 0.06	...	...

Notes:

Out-of-round use the sum of absolute values of plus and minus tolerances
This tolerance may not apply in localized areas of formed fittings where increased wall thickness is required to meet design requirements of para. 2.2
The inside diameter and the nominal wall thicknesses at ends are to be specified by the purchaser.
Unless otherwise specified by the purchaser, these tolerances apply to the normal inside diameter, which equals the difference between the nominal outside diameter and twice the nominal wall thickness.