Dear to All,
I have to design an expansion loops (U-shape) of five pipelines that run in parallel. I read the book by SAM KANNAPPAN "introduction of pipe stress analysis" where in Chapter 5 the expansion loops are explained, and I found these formulas to design them:

L2=SQRT(3*E*D*Expansion/(144*SA))
L2= W +2H

where:
Expansion= alpha*(design temperature-installation Temperature)*L
L=distance between two natural anchor point

Once I find L2, if all lengths are equal then L2=3*W and:
W=H=L2/3.

Is this simple calculations useful to design the expansion loops? or, are there other guides to be follow to design it?
Thank you

Dear,

Yes those calculations are useful.

Also try reading ASME B31.3, part 5, specially 319.4.1 Formal analysis not required where Dy/(L-U)^2 < K.

Regards.

I like Pablo's response and Sam's text may be useful but, of course, a typical response from a CAESAR II Forum is check your quick layout with a CAESAR II stress analysis.

Thank you for your replies.
Being the first time that I have to design an expansion loop, I tried to reason in this way:
I have a 1000 meters pipeline long (12"), with design Temperature=85C and installation temperature=21 C.
I calculated the thermal expansion of 1000 m pipeline= alpha*L*DT= about 750mm.
Now I divided the total length of 1000 m in five sections (200 meters each one); in each section i put an expansion loop(Finally I will have 4 expansion loops).In this way I divided the total expansion for each sections (each expansion loop will absorb 750/5= 150mm of expansion,75mm one side and 75mm on the other side).

I run the analysis by Caesar, I have a axial displacements lower than 75 mm (for operating case) and 130 mm (operating case+seism), and the loads at the guides lower than 1 ton.
Are these displacements reasonable? or I have to increase/decrease the number of expansion loops?

Thank you

Hi Aleps86,

I am also trying to figure out expansion loop design.

What you have done is pretty much what my senior told while explaining the design philosophy.

However, to judge how much expansion is bearable or within the limit, you have to refer to your company design manual or project/client design standard.

Thanks

Dear ishaf5,
thank you for your reply and now I am happier that other companies adopt the same design philosophy.