Nozzle Thickness on Spherical Tank

I am not trying to be spiteful nor malicious; but it seems you did not heed previous advice of contacting someone in person to help with this design, and particularly to avoid designing to Div 2.

Please, please, find a mentor in person.

Upss.. very sorry Sir.. Thank you for the suggestion..

I have proposed to my boss about your suggestion, but he kept strong with his decision. He told me to go straight, he promised me to invite the experienced one to review at the end.

Actually i am not satisfied with his decision. But i have no reason to disobey him.

Besides that, i have also asked to engineering forum in Indonesia and to my college mate who are now working in oil & gas EPC company..

Hopefully you can understand this decision.. By doing this, i wish i can learn a lot.

Thank you.

Need your more decision Sir..

4.5.4.1 The minimum nozzle neck thickness for nozzles excluding access openings and openings for inspection shall be determined for internal and external pressure using paragraphs 4.3 and 4.4, as applicable. Corrosion allowance and the effects of external forces and moments from supplemental loads shall be considered in these calculations. The resulting nozzle neck thickness shall not be less than the smaller of the shell thickness or the thickness given in Table 4.5.2.

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There are no explicit formulas for calculating reinforcing pad thickness/size - this is to allow the designer flexibility. It is based on the "area replacement" principle and you may choose thicknesses/lengths that suit other requirements. So make an "educated" guess for the pad, perform the calculations to determine if the allowable pressure suits your needs, and then optimize/add more thickess/area if required. (a conservative first start for the pad would be 3/4 the thickness of the shell with a width of 1.5*R_n/t_e)

Ok..

I will refer to par 4.3 & 4.4. Then which formshould i choose? Cylindrical or same as the shell itself, sphere.

And what about thickness of reinforcing pad, where can i find it?

Thank you. I hope you will not get bored to answer my easiest question :D

Nozzles are cylindrical shells.

There are no explicit formulas for calculating reinforcing pad thickness/size - this is to allow the designer flexibility. It is based on the "area replacement" principle and you may choose thicknesses/lengths that suit other requirements. So make an "educated" guess for the pad, perform the calculations to determine if the allowable pressure suits your needs, and then optimize/add more thickess/area if required. (a conservative first start for the pad would be 3/4 the thickness of the shell with a width of 1.5*R_n/t_e)

Sir.

Let me conclude this matter..

1. In calculating nozzle under internal pressure, i shall refer to 4.3.3 for cylindrical shells.

2. Then i refer to Par 4.3.9.2, to determine drilled holes

3. Then par 4.3.10 about Combined Loadings and Allowable Stress

Is it enough?

Then for 4.4 under external pressure, i will examine it later.. (i am still focus on 4.3). Maybe if you dont mind, you could give me the brief explanation Sir about par 4.4.

Thank you..

Thank you Xmech, I fully agree with your understanding.

Sami JR

www.techexp.co.cc

Dear friends..

Referring to ASME VIII-2 2007 par 4.3.3 for calculating nozzle thickness in sphere.

t = D/2 (exp[P/SE] - 1). Where, D is internal diameter (refer to nomenclatures par 4.3.13)

Then according to my P&ID, the size of nozzle is 10 inch. My question is, what kind of size is it in common? Outside diameter (NPS) or internal diameter?

Or maybe i shall refer to ASME B36.10 to find the standard wall thickness..

Thanx for the answer..

Yes, D in that case is the internal diameter.

The 10" in your P&ID is the nominal pipe size (10.75" Outer Diameter); therefore you must choose (guess) a schedule that you will require, determine the ID for that particular wall thickness [with B36.10M] (Don't forget to include pipe undertolarance and corrosion allowance in accordance with 4.1.3); run the calculation and determine if that choosen schedule is sufficient.

Got it Sir.. Thanx.

Next, lets assume that i choose "STD" for my identification of 10" pipe. So it means that my schedule is 40 according to ASME B36.10 and the wall thickness is 0.365 in

Then i calculate the internal diameter by subtracting this: 10.75 - 2 (0.365) = 10.02 in.

Last but not least, my internal diameter to be used for calculating the nozzle thickness is 10.02 in

Am i right Sir? Thank you very much..

I am sorry, I have decided that this has gone too far and I regretfully will not provide any more guidance/details.

Best of luck, and finally - Find a mentor in person and compensate them for their experience.