Flat bottom for pressure vessel 1

[Heyner]

Hi friends!

Will you helpme with this?

I need to design a gas boot for a FWKO tank, the boot is about 162in diameter and 470in height (yeah, it's big). Design pressure is 10 psig.

I want to know if ASME VIII-1 permits to design this vessel using a flat bottom and anchor bolts. I don't want to design it just as a flat cover since the thk would be about 2.5 in... (what i have in mind from a previous work like this is something like 1.25 in)

Floor and anchors help flat bottom to perform its work...Don't you think so?
It is to use elliptical head at top only...

Can you help me?

thanks,
Heyner

 

[prex]

No, for sure.
An (implicit) principle of ASME VIII is that the strength of a vessel must be only in its (metal) walls.
So you can do want you are planning only if you are not required to stay within the code.
This might be your case as the design pressure is lower than 15 psig, however you should check this carefully or consult a specialist in the field. prex

http://www.xcalcs.com

Online tools for structural design

 

[jte]

Hi Heyner-

Can you perhaps use API-620 instead of Section VIII?

I'm not a tankage expert, but it sounds to me like you have a perfect candidate for -620. From the 1996 edition section 1.2 Scope: "This standard covers the design and construction of large welded, low pressure carbon steel aboveground storage tanks (including flat-bottom tanks) that have a single vertical axis of revolution... The tanks described in this standard are designed for metal temperatures not greater than 250°F and with pressures in their gas or vapor spaces not more than 15 psig."

jt

 

[Heyner]

Hey boys, thanks a lot...

The problem is my customer wants the boot designed according to ASME BPV code...

But you gave me two ideas: API620 (try to make my customer understand) or two ell heads (standard tower).

Thanks a lot

 

[LSThill]

HI Heyner (Mechanical)

I have done das boot design.

ASME SECTION VIII, DIV. 1, using

http://www.Codeware.com

The HOME OF COMPRESS.

Contact me if you need any addtiona information.

Leonard@thill.biz

http://www.thill.biz

 

[JOHNPIA2]

I am quite familiar with Compress, but it does not directly address this situation. As I understand it, the flat plate bottom will be resting and anchored on concrete. A few months ago I did design something similar for a customer, using Compress; forget the self-standing flat plate formulas, they will be too conservative; to simulate the uplift due to the 10psi int. pressure, I introduced a lateral, fictitious force, to give the anchor chairs and bolts the equivalent tensile loads. Make sure you have enough a. bolts, and check local stresses on shell.

 

[Heyner]

Johnpia2:

You are right at all. But, in that case, I want to know if you agree with me, we can not say that vessel is an ASME sec VIII vessel. Is it?

Heyner.

 

[JOHNPIA2]

At 10psi int. pressure, the vessel is not within the scope of ASME; if you want to stamp it, your AI could accept the anchor chair design; it might be more economical to switch to a formed head+skirt design, making it 100% ASME!