API standard 650 tanks site-specific response spectra

API 620 Tank Design
The designer of these large tanks API standard 650 tanks shall supply the data on superimposed loadings to be assumed for the foundation design or, if there are no foundations, for direct loading on the subgrade. A slab or mat may be provided to support the superstructure and shall be considered to distribute the load more evenly over a lower natural subgrade compared with merely stripping, leveling, and rolling the existing grade.
For simple spheroids or tanks of similar design, in which the distribution of the imposed weights shifts because the liquid level in combination with the vapor pressure may change the shape of the tank, the designer shall consider the possibility of such a change.

Compared with the fixed roof API 650 oil storage tank without API standard 650 tanks floating roof, there is no evaporation space. In principle, this eliminates the so-called "large breathing loss". Evaporation not only causes the loss of product quantity, but also affects the quality of API standard 650 tanks product and pollutes the environment.

Compared with the external floating roof API standard 650 tanks, the internal floating roof API standard 650 tanks has the advantages of protecting the floating roof from wind and rain and ensuring the quality of liquid storage under the floating roof. At the same time, because the inner floating plate is in the tank, there is no rain and snow load, so the central drainage pipe and escalator and other accessories on the floating plate can be omitted. In addition, under the same sealing conditions, the internal floating roof tank can further reduce the evaporation loss compared with the External floating roof tank.