Storage tanks come in a wide range of shapes and sizes, from small 25-gallon tanks to gargantuan reservoirs capable of holding tens of millions of gallons. The best way to determine which kind of storage tank is right for you is to consider the following questions:
➤Application. What kind of product does your tank need to store?
➤Capacity. How much product do you need to store?
➤Budget. How much are you willing to invest in your storage tank?
With these questions in mind, continue reading to learn about the different types of storage tanks and which one would be ideal for the product you need to store.
Fixed Roof Tanks
Fixed roof tanks are cylindrical steel-welded tanks that have a cone or dome-shaped roof permanently attached to the tank’s shell.
Generally, these are atmospheric tanks, which means they can have an internal pressure ranging from ambient, up to 0.5 PSI. If pressures exceed this number, the tank becomes a low-pressure tank (0.5-2.5 PSI).
To maintain consistent pressure or vacuum inside the tank, fixed roof tanks are equipped with pressure-vacuum valves vents.
Fixed roof tanks can hold just about any kind of liquid product, including petroleum, water, chemicals, and pulp. Depending on the product, these tanks are built to either API 650/620, or AWWA D100. As for capacity, the sky is the limit.
Floating Roof Tanks
In contrast to fixed roof tanks, floating roof tanks have no affixed roof. Instead, as the name implies, this kind of storage tank is equipped with a platform (roof) that floats directly on top of the tank’s product.
There are two kinds of floating roof tanks:
➤External Floating Roof Tank (EFR): The floating platform is all that separates the product from the weather. The floating platform is the literal roof for the tank.
➤Internal Floating Roof Tank (IFR): Same as above, except this tank, is also equipped with a traditional steel roof that keeps the elements away from the floating platform.
As for application, while floating roof tanks can hold most liquids, they are primarily used in the petroleum industry. To learn about the pros and cons of EFRs & IFRs, read this blog post dedicated to floating roof tanks.
Horizontal Tanks
Horizontal storage tanks can be installed underground or above ground and are used in a variety of industries for the storage of light and heavy petroleum products, chemical solutions, water, food products, and other liquid products.
If intended for underground storage, horizontal steel tanks are given a number of coatings and insulations to prevent corrosion.
Pressure Tanks (High-Pressure Vessels)
While the terms “pressure tank” and “pressure vessel” are often used interchangeably, there is an important distinction between tanks and vessels. API 620 Tanks have a Maximum Allowable Operating Pressure (MAOP) of 15 PSI, whereas pressure vessels have internal pressures ranging from 15 to 3000 PSI (and higher under special provisions).
Pressure vessels are used across most industries and store a variety of products, including petroleum products, liquified gasses, and water. Vessels are built in accordance with the ASME Boiler and Pressure Vessel Code, which regulates pressure vessel design, fabrication, materials, testing, and certification.
Pressurized storage vessels come in many shapes, but the most common shape is a cylinder with end caps (heads). The shape of the vessel and the end caps are designed to meet the requirements of the product being stored.