Aboveground Storage Tank: Building an API 620 or 650 Tank for Your Needs

Aboveground Storage TanksMany industries rely on aboveground storage tanks (ASTs) to store different kinds of liquid materials. These include cryogenic materials and products with high internal pressure liquid materials. You may work in a new process facility, and you need to construct an AST. What tank will you construct?

You can build either of the two popular tanks today that conform to the standards set by the American Petroleum Industry (API). These tanks are simply called as API 620 and API 650 tanks, in relation to the API safety and reliability standards they follow. Now, even with these two choices, you may still wonder which of the two best suits your needs.

API 620

Before choosing a tank, it’s best to understand the standards that ASTs follow. The API Standard 620 requires an AST to be constructed atop a flat or elevated surface. The tank must only have a single vertical axis of revolution in its center, and its walls must be 3/16-inch-thick at the minimum.

Capabilities of the 620

An API 620 tank works best with materials that have high internal pressure, although you can store any liquid in it. The tank can resist up to 15 lbs. PSI and can endure temperatures from -325 to -250 degrees Fahrenheit.

API 650

In contrast, the API Standard 650 covers ASTs that are cylindrical steel tanks with open and closed tops and various capacities. Tanks with even bottom support, non-refrigerated service, and 200 degrees Fahrenheit maximum design temperature. The wall thickness of the tank is the same as API 620.

Capabilities of the 650

You can construct an API 650 AST of any size and it will be able to hold oil, gas, chemical, water, and biofuel materials. It has a maximum 2 1/2 PSI and a temperature range of -40 to 500 degrees Fahrenheit. Most process facility ASTs are API 650 tanks.

Now you can better choose which tank you will construct for your process facility. You can consult with a liquid storage tank services provider for more help on your planned AST.