Hi,

I'm using CAESAR II 4.5.
Upon selecting B31.4, no allowable stress values appear.
Any idea why??

Also, If I'm modeling a 50 meters vertical pipe (clossed loop chilled water system)and I specified a pressure of 15 Bars at the bottom, Will CAESAR II "feel" the difference in pressure at the top??

Best Regards,

With regards to B31.4, check the Code equations in the CAESAR II Quick Reference Guide. Based on the load case type (OPE, SUS, EXP, OCC), and whether the pipe element is in tension or compresssion, the B31.4 doesn't define an allowable for certain conditions.

With regard to the pressure head - "no". The pressure in the pipe is the pressure you specify on the spreadsheet.

I´m facing the same problem. Im analazing a scraper trap line, so, i have unrestrained (above ground) lines and restrined lines (buried with soil restraints modeled). In may opinion in this conditions there would be allowable stresses, but there isn´t.
Wich would be the cause?

Regards.

Dear Mr.Richard,

In caesar input spreadsheet, to define the ASME B31.4 Code allowable stress, there is an provision to enter it. My clarification is that do we have to enter the value of Sy or SMYS in that option.

Since as per ASME B31.4, the allowable stress is calculated as

Sy = F*E*SMYS

I am confused with the sentence provided in the help option, please clarify it...

You should enter SMYS.

Dear Mr. Richard,

Thanks for your reply, and one more doubt is how the design factor F shall be considered in allowable stress, if we have two different F values...

Dear Richard,

I am waiting for your reply... Please response for it...

The F in CAESAR II is only used (as F1) in Chapter IX. If you want, you can change this on each pipe element.

Where do you find this Sy = F*E*SMYS in B31.4. It appears to me that all allowable stress limits reference SMYS and not an Sy.

Dear DaveDiehl,

It is given in ASME B31.4, Section 402.3 - Allowable Stress and other stress limits....