API 650 flat-bottom tanks secondary seal

The factors affecting the "small breathing" loss of API 650 flat-bottom tanks are: 1. It is related to the change of temperature difference between day and night. The greater the change of temperature difference between day and night, the greater the loss of "small breathing"; on the contrary, the smaller the change of temperature difference between day and night, the smaller the loss. 2. It is related to the sunshine time of the oil storage tank. The longer the sunshine, the more the "small breathing" loss; otherwise, the less the loss.

Uplift on Foundation
For API Standard 620 tanks with an internal design pressure less than 1 lbf/in.2 gauge, the uplift shall be taken as the smaller of the maximum uplift values computed under the following conditions:
a)The internal design pressure times 1.5 plus the design wind load on the shell and roof.
b)The internal design pressure plus 0.25 lbf/in.2 gauge plus the design wind load on the shell and roof.

API 650 can store oil, gas, chemical, water and biofuel for some of the most common tanks in the oil industry. API 650 can store contents at a lower pressure (maximum of 2 PSI) but at much higher temperature (-40 degrees F to 500 degrees F) than the standards of API 650 flat-bottom tanks. It can be any tank size.