Tangent pipe length in pipe bend?

80 NB Pipe - This should be DN80 (metric designation for 3" NPS pipe)

10 D = 30" to 32" or 5 D = 15" to 16" bend tangent length is 350 mm (14") both end.

If I do not maintain this tangent distance then what will happen?.. Nothing will happen
Kindly tell me your valuable feedback..

The straight length (Tangent distance) at each end of a Bend is there only for the purpose of making the Bend
The Bend machine needs to grip both ends of the pipe so it can "Pull" the pipe around the pipe bend form. The pipe is heated up to the required temperature. The straight pipe at one end is clamped in at the fixed post (before the bend). Enough pipe is left to form the bend then the other end of the pipe is clamped to the "Pulling Block". When the pulling block rotates the pipe is pulled around the form and then left to cool. After cooling the angle is checked, corrected if required and then removed from the machine.
The ends may be left on or the ends can be trimmed off at a designated point (at the tangent point, at one diameter or some other length). Sometimes the extra length can save a weld in the shop depending on the pipe spool configuration.

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