Atmospheric Tank [1]
A storage tank [2] in which product is stored at ambient pressure–that is, at the pressure of the atmosphere at the location of the tank.
Atmospheric tanks are designed to operate at pressures ranging from the pressure of the atmosphere, itself, through 0.5 psig. The pressure measurement is made at the top of the liquid. Typically, atmospheric tanks are vented directly to the surrounding atmosphere. All underground storage tank [3]s at gasoline stations are atmospheric tanks.