CODE CASE 1876-3

Dear Sirs,

I am checking the stresses for SUS+WIN and I found out that the code stress ratio exceeds.
My boss gave me this code case to check if its still in the allowable stress.

So, my question is, does it has a similar consideration in using that code vs. sus+occ case?

Could you suggest some technical knowledge about this?

Code Case 1876-3?

The only Code Case I can find is a BPV Code Case which provides a higher allowable stress limit for safety valve connections while the valve is blowing steam.

Is this what you are using to qualify your wind loading?

Yes you are right.

I am not qualifying my SUS+WIN with that code case.

Just, they gave me this reference-design of safety valve connection- and said that I could use it.

It is true that there's allowable there...but its different.

Please advice.

I know not what advice you seek.

I see no clear link between the criteria to evaluate B31 sustained and occasional loads and the criteria to evaluate stresses caused by relief valve loads as found in BPV Code Case 1876-3.

The B31 codes permit the use of "more rigorous methods" of analysis and evaluation but I cannot say the Code Case is more rigorous.

thanks dave. Will I just follow what they said? Even it has no link between that two?

liam start at the beginning what code is your piping being designed in accordance with?

we're using B31.1

The code case is for a power boiler nozzle, only. And it discusses only what s value(s) may be designed to when the valve is firing (lifted.

It does not discuss wind nor seismic loads nor thermal displacement loads.

In a sense it is similar to the approach used by B31.1 for all occasional loads.... but wind is not mentioned.

Thank you so much Dave and John. I can now have a good sleep tonight.