What are the design criteria for low-pressure storage tanks and atmospheric pressure storage tanks?

It’s rare to see the boss post anything: lol. In my opinion, it depends on the relative volatility and vapor pressure of the storage medium.

This post was last edited by caya on 2015-8-28 at 16:05. The definition of a storage tank at normal pressure is easy to understand; the definition of a low-pressure storage tank is one whose design pressure is greater than 6.0 KPa and less than 0.1 MPa (gauge pressure at the tank top). Regarding whether to use atmospheric-pressure or low-pressure storage tanks, refer to the regulations in the standards: — For storing Class A/B liquids with a boiling point below 45 degrees Celsius, or those with a saturated vapor pressure greater than 88 KPa at 37.8 degrees Celsius, pressure storage tanks, low-pressure storage tanks, or atmospheric-pressure storage tanks with temperature reduction should be used ； ——For storing Class A and B liquids with a boiling point of 45 degrees or higher, or with a saturated vapor pressure of no more than 88 KPa at 37.8 degrees, floating roof tanks or internal floating roof tanks should be used. For other Class A B and Class B A liquid chemical products that require special storage conditions, fixed-roof storage tanks, low-pressure storage tanks, and horizontal storage tanks with a capacity of 100 cubic meters or less can be used.

I see. I always thought that 18 KPA was the threshold, with some saying 6.9 is the dividing point; I need to check the original specifications – API 650/620/625 and other standards related to low-temperature double-walled tanks – to see if there are any changes in the original texts

Thanks for sharing. What standards should be adopted for the design of water storage tanks regarding excess medium?