WRC 107/297 Local Shell Thickness Consideration

Thats an odd question. Usually if you read it you find it. If you dont find it it maybe is not in there.

Assume you dont have the code? Which source says its in there?

Any luck here:

http://www.whatispiping.com/wrc-107-and-wrc-297

http://www.scribd.com/doc/80346231/WRC#scribd

???

Dear Sir,

I could fully follow your comments. Could you please elaborate. Also both the links as shared are not working at my end. If the links are for bulletin then i have a copy of it. But going through it i was not able to find the same.

If someone who had already been through this documents several time and know in depth shares this information than i shall really appreciate.

Thanks and Regards

So you could NOT fully follow my comment.

Not sure why the links not working. But I made an internet research for the Code/Bulletin in question and came up with these links. You might want to do the same.

Now that you say you have the bulletin I am at a loss why you ask whats written in it.

Here is an extract from the second link which might mean there is not such an allowance in the mentioned documents.

WRC-107, entitled "Local Stresses in Spherical and Cylindrical Shells due to ExternalLoadings", was released in 1965 and updated in 1979. WRC-297 was released in 1984 andgoes under the title of "Local Stresses in Cylindrical Shells due to External Loadings - Supplement to WRC Bulletin No. 107"

• Both deal with "local" stress states in the vicinity of an attachment to a vessel or pipe. Asindicated by their titles, WRC-107 can be used for attachments to both spherical and cylindricalshells while WRC-297 only addresses cylinder to cylinder connections. While both bulletinsare used for nozzle connection. WRC-107 is based on un-penetrated shell, while WRC-297assumes a circular opening in vessel. Both bulletins assume that the nozzle (or attachment) axisis normal to the vessel. Furthermore, WRC-107 defines values for solid and hollow attachmentsof either round and rectangular shape for spherical shells but drops the solid/hollow distinctionfor attachments to cylindrical shells. WRC-297, on the other hand, is intended only for cylindrical nozzles attached to cylindrical shells.

• The cook-book approach found in WRC-107 resulted from the analytical work of Prof. P. P.Bijlaard and assume a shallow shell theory for spherical shells and flexible loading surfaces for cylindrical vessels. Therefore, WRC-107 requires that the Dm/T ratio be greater than 50 andlimits the d/D ratio to below 0.3.

• WRC-297 can be applied to a larger d/D ratio (up to 0.5) since the analysis is based on adifferent, thin shell theory (derived and developed by Prof. C. R. Steele).

• WRC-107 only computes the stress states of the vessel/header shell while WRC-297 also provides stress states for the nozzle/branch connection. WRC-297 also provides calculationsfor nozzle/branch flexibilities.

• Neither bulletin considers shell reinforcement nor do they address stress due to pressure.

Good question..... wrong forum !

Suggest that you post and search on the "eng-tips" forum (under boilers & Pressure Vessel forum)

Or..... consider the Forum that supports the COMPRESS pressure vessel computer program (www.coade.com)

This question has been asked before on both of these for a..

Looks like you in the wrong forum too!

Why is this important? If the local stress is exceeded, then the only way around it is a thicker vessel, or possibly a reinforcing pad, is it not?

Why try to engineer something right up to the edge of failure, when you can easily make it withstand conditions that even you might not foresee? Why not engineer in an extra safety factor?