MODELLING CROSSES IN PIPING SYSTEM

There is no option for modelling crosses in piping system. If I model using SIFS AND TEES OPTION WARNING IS COMING SUCH THAT NO SIF CALCULATED FOR THIS INTERSECTION. Please clarify how to model crosses.

:rolleyes: :rolleyes: :rolleyes:

do a search on cross, and look at your piping code book for the SIF for a cross

P.Manivannan,

Welcome to the discussion forum.

I assume you are using an ASME B31 code. The simple answer to your question is the codes do not deal with crosses. For further information click on "search" above (immediately below the New Topic and Post buttons). Search on the word "Cross." The topic entitled "Cross Tees" has a very clear answer to your question from forum moderator, Richard Ay.

Regards,

I had that Problem. I discovered that autoPIPE made provision for modelling crosses. I got around that problem in C2 by using two intersection points (with a gap of about 0.01" between the two intersection points. That way I was able to specify SIFs for the cross. Most of the crosses i've seen are the forged type, so you may specify "welding" for the SIF or if you have a specific value, use that value.

Regards

Amachree

Autopipe, is that some sort of code authority?

Nope not really. But I was wondering, since crosses are part of fittings specified by B16.9. Shouldn't there have been a provision for it in the code. If Markl did not include it in his work, shouldn't there be some form of discussion to make provisions on how it should be included in the codes.

Regards
Amachreee

See B31.3 2004, para.319.3.6...

Designers choice!

However, if you want you are welcome to put together a series of fatigue tests and subsequent proposed SIF for crosses. And then send it to the comittee for their consideration.