no W weld joint strength reduction factor in sec 8 - why ?

B31.1 & ASME Sec VIII Div 1 stress basis are similar; still, when B31.1 has adopted W, why not in Sec-VIII Div-1 too ?

reg,
sam

PS: This is not directly related to Caesar-II; but, all vessel engineers may not know what is W;so in this forum, I raise this query. I have not read latest 2015 Sec VIII Div-1 yet!

Hi Sam,

Just want to understand, why you want to design the pipe as per ASME Sec-CIII div -1?

And where do you find weld joint strength reduction factor in B 31.1?

Regards,
R.K.

Simple!

"why you want to design the pipe as per ASME Sec-VIII div -1"

where mechanical equipment welding jurisdiction is there.

In B31.1:2010, W is there in table 102.4.7: you may be bit slow in adopting new code revisions!

reg,
sam

Ok, Thanks. I was having an old copy and really unaware about 2010 edition of B 31.1, Since I never worked on power projects from long time.

As far as I understood the Section VIII code, the code provides the joint efficiency as per UG-27. Weld joint efficiency E is a factor which incorporates deficiency in the joints because of structural weaknesses of weld joints and reduces the overall stregth.

While the weld strength reduction factor incorporates the reduction in strength due to creep phenomenon at elevated temperature.

Since ASME Sec VIII div 1 code does not have a procedure for fatigue/creep calculation, this can be the reason why ASME SEC VIII div 1 does not consider that.
Section III does have effect for creep and fatigue method. If you can use that in Section VIII deiv 1? this can be a matter of discussion.

Comments are welcome.

Regards,
R.K.