Pipeline Bends - Minimum Bending Radius
Pipeline Bends - Minimum Bending Radius
(OP)
Which is the limiting minimum elastic bending radius for Pipeline bends( for Gas Flow Lines):
- The one stated in ASME B31.8 section 841.231 OR
- The one given by equation : R(min) = (3EI)/(2ZS).
where E = Modulus of Elasticity
I = Cross sectional moment of Inertia
Z = Section Modulus
S = Allowable Stress
- Or any other consideration for this.





RE: Pipeline Bends - Minimum Bending Radius
You have the choice of what are called standard elbows or swept bends. I forget the respective ratios but any piping supply company will know. Regards DW
RE: Pipeline Bends - Minimum Bending Radius
For elastic bends 50D
For plastic bends (with a bending machine with an internal mandrel) 15D
For hot induction bends (i.e. manufacured by a mill) 5D. This latter limit was forced by the pig manufacturers, as the minimum radius an typoical intelligent pag can go around is 5D. if you're not going to use intellignet pigs, you might be able to reduce the minimum radius futher.
RE: Pipeline Bends - Minimum Bending Radius
Some pipelines are required to be constructed to allow for the use of smart pigs by DOT code.