In CAESAR II help for subject, it is given:
"B31.3 states, "The sum of the longitudinal stresses due to pressure, weight, and other sustained loadings (S1) and of the stresses produced by occasional loads such as wind or earthquake may be as much as 1.33 times the allowable stress given in Appendix A. Where the allowable stress value exceeds 2/3 of yield strength at temperature, the allowable stress value must be reduced as specified in Note 3 in 302.3.2." The default for B31.3 applications is 33%. If this is too high for the material and temperature specified, then a smaller occasional load factor could be input."
In ASME B31.3 2014 edition, I could not find the note 3, or any other point stating that occasional load can be reduced based as stated above.
So is this help updated or needs to be updated.
Correct me if I am wrong.
For elevated temperature there is a clause in ASME B31.3 (302.3.6) whereby it is stated that allowable value can be reduced. But for other temperatures no such permission is given.
Kindly give your opinion.

I cannot find your quotation in B31.3. What edition (year) are you quoting?
The last paragraph in 302.3.6(a) speaks of reducing the allowable stress (not loads) of castings. There is no reference to note 3. That paragraph references 302.3.2(e). But this paragraph does not mention elevated temperature fluid service.

Hi,
As per clause no. 302.3.6 (a) of ASME B31.3 2014 edition as follows:

For Elevated Temperature Fluid Services, allowable stress values for occasional loads of short duration,(such as surge, extreme wind or earthquake) may be taken as strength reduction factor times 90 % of yield strength at temperature for material having ductile behavior.

Query: In above statement, 90% of Yield strength to be taken at ambient temperature or at fluid operating temperature ?

Metal temperature, which is likely fluid temperature.

Thanks a lot Dave Diehl for your prompt response.

With reference to clause no. 302.3.6(a) of ASME B31.3 2010 & 2014 edition

Query 1: Does Caesar (v6.0 & v8.0) take that allowable stress values into calculation for elevated temperature fluid services ? Or Does it simply take 1.33 times hot allowable stress at corresponding temperature?

Query 2: Does ASME code consider longitudinal stresses due to sustained loads component while taking allowable stress for occasional loads of short duration,(such as surge, extreme wind or earthquake) is equal to strength reduction factor times 90 % of yield strength at temperature ?

1: CAESAR II uses 1.33*Sh as the allowable limit for the sustained plus occasional stress combination. As a user you can adjust the 1.33 term.

2: No, the Code does not extend the 90%Sy limit to sustained stress evaluation.

Thanks Dave,

Can you tell me how to adjust that 1.33 term ?

In the configuration file, go to SIFs and Stresses. Under Code-Specific Settings you will see "Occasional Load Factor 0.000". This 0.000 indicates that CAESAR II shall use the code default and for B31.3 this is 1.33. If you wish to use a different multiplier for Sh in the SUS+OCC evaluation, type it in here. You will have to run your model through the error checker to register this change in your analysis.

Dear All
I have the question about the OCC load factor but acc. EN 13480.
I found in different topic
EN13480 and factor K ( dead + wind or earthquake )
that in CAESAR II if You give OCC factor "0" the program use the default factor from the active piping code. It was written to CAESAR II ver. 5.
My question is:
If the same situation is in the newest version CII 2017 ???

Yes, a value of 0 indicates that the default value from the Code will be used. The EN 13480 code provides a minimum value of k=1 (in k*f-sub-f) for loads which act for more than 10% of any 24 hour period (other k's are 1.15, 1.2, 1.3 & 1.8). CAESAR II uses this k=1 as the default value.