×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

API 620 tank design
4

API 620 tank design

API 620 tank design

(OP)
hello

i am designing a vertical storage tank per API 620, i find this standart quit difficult to work with, specially when designing the shell and the roof, i could use a sample of the calculation, if possible, or any advice,

thank you in advance

RE: API 620 tank design

You don't need a sample. You need 10 years of experience, or someone you can learn from.

RE: API 620 tank design

I agree with IFRs. Given the great variety of tank design options available with API 620, a sample is unlikely to do you much good. It could also be dangerous for you to believe you have the skills necessary to design such a project. Lawsuits are expensive, consultants are not.

RE: API 620 tank design

I believe there are some sample calculations in one of the Appendices/Annexes, I don't remember what all they cover.

The main issue with the standard is that it's written in such a way that it can be applied to a variety of tank shapes, which makes it much less of a cookbook approach.

RE: API 620 tank design

(OP)
thx guys, that's actually what i needed to know, because i was starting to lose confidance in my skills,

i still have another question:

how long do you think it could take me to design a large vertical storage tank per API 620 now that you know that i have practically no experiance in this field ?

RE: API 620 tank design

aliienitmeca,

The length of time it takes to design is proportional to the size. "Large" is insufficient information to determine appropriate scale.

RE: API 620 tank design

(OP)
fegenbush

i dont see how the size of the tank is related to the time of the design, i beleive it has only to do with understanding the design steps, and calculations should not take a long time,

i would apreciate if you further explain your point

thank you

RE: API 620 tank design

alienitmeca,

Depending on your background, you may think that a 20ft (6.09m) diameter tank is large. In comparison to most of the tanks I build, it is not. However, the larger the diameter, the more consideration is required for structural support of the roof, the shell-to-roof joint, anchorage, and foundation design.

On an API 620 project, determination of the thicknesses of the shell, roof, and floor plates are quick in comparison with the design details required for the aforementioned items. As an example, many customers request a single large tank (~150ft / 45.71m) which is physically possible, but not economical. Additional design considerations also come with refrigerated tanks or other low temperature service.

I hope that we have not been too discouraging to you, but it would be wise to seek a consultant on this project.

RE: API 620 tank design

(OP)
fegenbush

actually, i am not designing the tank according to a specific diameter, i am suppoosed to establish a design procedur to be used for any tank dimension. i have already done one per API650, the one per API620 remains, so, as i already said, any example could be very helpful in my situation.

thank you

RE: API 620 tank design

650 is limited to one basic design while 620 tanks can take many shapes. You have your work cut out for you on this one! And you are building yourself a model that will need to be updated regularly as each code is updated and revised. You may be better off buying commercial software that is maintained as the codes change. I trust you are using the most recent version of each code now? I hope that the people using your design guides will have their work checked by an expert.

RE: API 620 tank design

(OP)
IFRs

i am using the recent editions of both API620 and API650,

to reply to your question, no it will not be checked by an expert, however, it will be drawn on CAD software and tested .

RE: API 620 tank design

alienitmeca,

As IFRs mentioned, API620 allows for a myriad of different geometries. Is your design going to be flat-bottomed like an API650 tank? Will it have conical sections? Will it be vertical or horizontal? Is it leg-supported, skirt-supported, saddle-supported, etc...?

I've gone through a few designs (by no means an expert if something unusual came up), but I know enough to wish you good luck in developing a single design procedure. API650 is like a cookbook for one type of geometry, API620 is everything else.

Sorry, I don't have any examples I can provide.

Good luck.

RE: API 620 tank design

(OP)
marty007

thank you very much for your support and recomendations, as well as all other friends,
i believe am getting better every time i re-read the standard, i am sure it's gonna be a matter of time now.

thank you

RE: API 620 tank design

2
alienitmeca,

The person who assigned to you this important, complex engineering tank design assignment...... does he have an MBA ? ? ?

MJCronin
Sr. Process Engineer
Venture Engineering & Construction
www.VentureEngr.com

RE: API 620 tank design

(OP)
MJCronin,

i don't know that, but he has 6 years oil&gaz-related experience , however this is the first time he works on low pressure VST,

but i don't see the point of this question, could you explain more ?

thank you

RE: API 620 tank design

I believe that MJCronin is aluding to a manager trying to save money by asignining a junior and/or inexperienced engineer to design his tank. Instead of hiring an experienced and fully qualified consultant to do the work.

But I could be wrongglasses

RE: API 620 tank design

(OP)
Duwe6,

you couldn't be more right, actually it's the strategy of the whole company, not my senior, any way i must have this job done perfectly. 1 month ago i new nothing about API 650, now i master it, and i am getting better every day in using API 620. i am getting a great deal of experience out of this project.

thank you for you support

RE: API 620 tank design

"master" is a pretty strong statement, I'm curious - how thick are your manway necks?

RE: API 620 tank design

(OP)
IFRs,

i agree with you, "master" is a pretty strong statment.


IFRs, thank you for the advice.


RE: API 620 tank design

(OP)
hello,

i have two questions that are related to shell design per API 620 :

-how to determine the number of courses constructing the shell, and the relative hight (h) of every course

- in the example (F1) given in APPENDIX F ,the assumed thickness in the beginning is t=3/4 in, i don't see how to choose a thickness for my case of design (is it t=3/4? , if not how do i know the right one?)

this is too important!!
thank you in advance

RE: API 620 tank design

Shell course widths are controlled by material availability, fabrication equipment and capacity, shipping restrictions, and field handling restrictions. This is not a question we can answer for you, since we do not know the specifics of your location or that of construction.

The design procedure is assume a thickness -> calculate required thickness -> modify assumed thickness -> repeat as necessary.

RE: API 620 tank design

(OP)
fegenbush,

thank you for your reply, that was quit helpful for the determination of course number,

but i still don't understand how the first assumed thickness is obtained !! could you explain how to may i get it, since the sample F1 in appendix F per API 650 have choosed 3/4 in !!

thank you in advance

RE: API 620 tank design

It is an iterative approach. You must start somewhere, anywhere, then converge on the minimum thickness. If you choose to start at 3/4" as *your* rule, that is fine, but for some tanks it may take a few iterations to get the final solution.

RE: API 620 tank design

(OP)
fegenbush,

thank you, that was really helpful,


i have another question concernig the roof and bottom design;

- API 620 does not give any specifcations about roofs that need internal structure, where could i find the the Standard that gives such specifications?

- as far as the bottom is concerned, do i use the same design per API-650 (central plates and annular plates (if needed)), if not what should be the criteria for the bottom design?

thank you in advance

RE: API 620 tank design

Hi !

Could I use this thread to ask a few questions (I did not find in API 620 / 650 hints or answers regarding these issues) :
- in designing my storage tank, are there some guidelines regarding the diameter / height ratio to observe ?
- do I need to leave some minimum space around the tank in my retention volume ?

Thank you !

RE: API 620 tank design

Tank diameter/height ratios and rules-of-thumb therein are based on years of experience designing and building tanks to find out what works and what doesn't. Sometimes the customer pays attention to the decades of experience that the tank contractor possesses, and sometimes they do not. Disregarding the value of this experience and the recommendations it produces are costly mistakes.

Minimum tank spacing is controlled by a number of factors. Often, the local jurisdiction will reference specific codes if the tank is to contain combustible materials (e.g. LNG). NFPA 30 is the most referenced specification in this regard.

/I do plan to get back with the original poster on his new questions, but ballots are due in this week.

RE: API 620 tank design

Tank height is often controlled by foundation capacity and sometimes restricted by local zoning.
Wind and or seismic considerations can make a lower wider tank more economical.
Available steel grades and thicknesses may limit your height.
I did my negatives first, then all but 12B.
Working on that one...

RE: API 620 tank design

(OP)
DaniMP,

as far as the tank diameter/height ration, you could check Table A.1a—Typical Sizes and Corresponding Nominal Capacities per API 650, it could help.

RE: API 620 tank design

(OP)
Hello,

API 620 does not specify when annular bottom plates should be used, could you indicate when they must be used

RE: API 620 tank design

Recently I read an "in house" storage tank specification which ended up a mixture of specifications. The intent was good, but one cannot short circuit the tank selection data, design requirements, and installation preference for any particular company. These all need to be separate, but can be included by having different sections with-in the specification. I can see where an inexperienced manager may assign a task of this nature to a junior engineer, with the objective of developing a "simplified design" but take notice of the advice stared in the "Special Notes" of API 650 (05/11/2011) - "Users of this standard should not rely exclusively on the information contained in this document". Sound business, scientific engineering and safety judgment....

Only fools rush in where other fear to tread.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources