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Hi, Good day! I am designing stainl

Hi, Good day! I am designing stainl

Hi, Good day! I am designing stainl

(OP)
Hi, Good day! I am designing stainless steel and sometimes mild steel storage tank. Our client and my boss always give me the dimension, what liquid to be stored, and design pressure full of water. I always design those tanks using API 650 - Annex V for external pressure. Since there is no data. I always used the maximum which 6.9 kPa. Knowing that I will get a over design tank.

Anyone can help me what is the best assume between 0.25kPa and 6.9kPa for external pressure since it's not specified.

RE: Hi, Good day! I am designing stainl

Per API-650, the default external pressure is 1" water column for regular tanks, or zero for tanks with circulation vents per Annex H. See 5.2.1(b).
If in doubt, that's a question for the purchaser and also needs to be coordinated with sizing of vents.
On a small tank, it may not make much difference, but on a large tank, it will.

RE: Hi, Good day! I am designing stainl

Quote (Hi, Good day! I am designing stainless steel and sometimes mild steel storage tank. Our client and my boss always give me the dimension, what liquid to be stored, and design pressure full of water.)


You may design for pressure full of water for test conditions if G of the content is 1.0 or less than 1.0. There are liquids which the relative density G =1.7 or more which your approach will not be correct.

Quote (I always design those tanks using API 650 - Annex V for external pressure. Since there is no data. I always used the maximum which 6.9 kPa. Knowing that I will get a over design tank.)


The vacuum pressure shall be decided acc. to size and no. of PV valves and typical internal vacuum is 1 or 2 in WC . For atmospheric tanks vacuum breakers, open vents or PV valves are provided to avoid vacuum collapse . The vacuum pressure should normally be specified by the purchaser.

What are the size of the subject tanks ?

RE: Hi, Good day! I am designing stainl

(OP)
JStephen and HTURKAK, the dimensions of the tanks are

11.56m dia x 10.10m height - 2pcs.
12.4m dia x 16.245m height
8.4m dia x 13.52m height
8m dia x 10.48m height
3.95m dia x 5.52m height - with frame.

That's the problem. Always dimensions and location only are the given data. Even soil data was not present.

I have another question regarding of foundation settlement. I designed the tank foundation with mat footing and getting excessive settlement ranging 75-90mm. I don't know if it safe. Rebars and soil bearing cap is already safe, but I doubt with the settlement. Based on your experience, do you have any idea what is the acceptable settlement for the foundation of tanks.

Thank you so much guys. God bless.

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