Maximum Bend radius

[jgibbs22]

Hey Everyone, a question came up the other day as follows:

What is the MAXIMUM pipe bend radius for elbows? While the question may be broad in answers, the specific piping in question at the time was schedule 10. Is there a standard somewhere that specifically discusses this? It would be for stainless steel pipe.

Thanks everyone!

 

[MJCronin]

gibbs....

Although there exists MINIMUM bend radii for various types and schedules of piping, I do not believe that there are MAXIMUM bend radius limitations.

There are ASME piping code limitations on the amount of "waviness" permitted on the intrados of the bend.

There, of course, exists a "Piping Fabrication Institute" standard (PFI ES-24) defining limitations on "minimum radius bending".

There were discussions about this topic on this thread:

http://www.eng-tips.com/viewthread.cfm?qid=202545&page=73

-MJC

 

[Pulpeng]

I suppose the maximum is infinity and the pipe ends up being straight. Or I suppose if you go past infinity and end up on the other side it's at the point where you reach the negative minimum bend radius.

Never heard of a maximum.

 

[DSB123]

gibbs,
The maximum limit is the capability of your bend pulling machine or as Pulpeng says the maximum bend radius is infinity where the pipe is straight.

 

[zdas04]

When field bending for pipelines, it is common to have a bend radius over 100D. Much greater than that and you have straight pipe (you have to look pretty close at a 100D bend to even see that it is bent).

David

 

[kepharda]

What is the MAXIMUM amount of space you have to install the elbow into? 100D is pretty common on Construction Specs.

Ahh answering questions with questions, man I am getting old.



this message has been approved for citizen to elect kepharda 2008

 

[MrBTU]

Often times, if you need a very large bend, you go with a "normal" radius 90, then a straight section, then another 90 so it looks like a square end rather than a U.

 

[C2it]

I guess the real limit is the curvature of the earth's surface, since all 'straight' pipelines actually bend around it. That's a big bend radius.

 

[SNORGY]

I think when the original question was posed it was probably intended to mean, "What is the maximum extent to which you can bend pipe?" or something similar. In other words, by "maximum bend" they probably were indeed trying to find out "minimum bend radius".

The question makes no sense to me otherwise.

Regards,

SNORGY.

 

[eadwine]

As for the required max/min bending radius for pipe, this is dependent on the pipe diameter and thickness. It all has to do with allowable thinout in the outside radius and dimpling on the inside radius.

As for pipe fittings (elbows)those radii are established in the std's necessary to produce a standardized product.