ASME Sec I welded nozzle calcs

[GenB]

Hello, Can any one help in clarification of PW16.2fig PW16(d)
t1+t2>=1.25 Tmin
t1 and t2 shall each be not less than "the smallest of 1/4" or .7 x Tmin
shell/pipe 16" .375 nozzle .534" nps 6in long,
Q=what size of fillet weld?
Q=what it will be Tmin? (PW16.2 nomenclature sec.I page 93

Thanks,
ER

 

[GenB]

Correction;
The nozzle is 4"nps(4.5" D) with extra heavy wall,
Thanks,
ER

 

[eboelen]

t sub min is .375 as defined on p93, being the minimum of .75, .375 and .534.
so .7 x t min is .2625 and 1.25 x t min is .468

the second condition makes t1 and t2 each > .25 which results in t1+t2>.5 which then automatically makes t1+t2> .468
You call this nozzle extra heavy (XS) but the wall thickness you list is for a sched 160.
XS is .337 and XXS is .674 for 4" nominal.
Make sure you have a sched 160.

Eric

 

[GenB]

Thanks for your answers. You are right it is sch 160, 'sorry.
When you say "t1+t2>.5 which then automatically makes t1+t2> .468" don't t1+t2 must be > .5 (or each >.25)
then if we only have .468" are we still in compliance? and what will it be the minimum size of the weld?
when at the verification part there is certainly a reduction.
Why is the verification important and why the Code contradicts itself? it is not mentioned anywhere else.

The verification part (see A-66 end-page 189)
I hope this makes sense.

I am also loking at example calcs on page 88 pw-15(a)
weld strength calcs with a diferent formula which increases the weld strength as much as 20%, I do not understand why. Do you?
Thanks for your time,
Regards,
ER

 

[GenB]

Eric:
Thanks, with a little work I finally understand the calcs perfectly. (I also consulted an older edition of the Code which explained a little better)
Now I am looking into the Code where it says:
no weld shall be smaller than 1/4"!
I am sure I will find it. I'll be back...
Thanks again,
ER

 

[eboelen]

ER,

it says tyhat on the figure at PW16.d,
weld shall be larger than the smaller one of 1/4" .....


Eric

 

[GenB]

Hello. How's the new year.
For this job is okay.

My question is:
Is there a minimum size of fillet weld in sec I?
Some Engineers think that it is 1/4" the minimum weld legs allowed as specifications in drawings: "no weld leg shall be smaller than 1/4".
Is this just a precaution to tell the fabricator the minimum design allowed by the designer or is it the code requirement and why?
It is my understanding that some fillet welds can have a smaller leg according to the calculated fillet weld design.
Thanks,
ER

 

[GenB]

I reserched a little,
Q= is there a code case for small nozzle weld size requirements?
I look into old code cases and there is no address as to the min weld size required, I heard of sec I working in the matter.
ER