API Standards for Storage Tank Fabricators

White Storage TanksThe American Petroleum Institute (API) laid down guidelines in 1961 to build the best storage tanks – whether it is for oil, chemicals, or other materials required for the operation of a refinery.

Storage tanks are now being used for other purposes as well. Fabricators must adhere to the API 650 for all aspects related to a storage tank – materials, designing, fabrication, installation, and inspection. This standard lets the owner have some flexibility as long as minimum requirements are met.

Keys to the API 650 Tank Standards

Since there is a lot of flexibility for using these standards, it is essential to focus on how the components can be used to make the best tanks.

Material: Carbon and/or stainless steel are the most common materials used for oil storage. There are regulations governing alloys, temperatures that a plate can be treated with, impact tests, and strength required. The API mentioned all of these specifications on a chart.

The Quality of welding: As tanks are made with a number of plates, the strength of the welding is important. Welds have to be compatible with the materials used and what the tank will hold. Additional issues to address are the tank’s foundation, allowance for corrosion, and many other essential components. The API 650 standard also covers items, such as gaskets, nozzles, and valves.

Plate Integrity: One of the main issues during the fabrication process is plate integrity. Facilities that construct storage tanks have to be large and free of compounds, which could corrode steel. The plates have to be packed well to protect them during transportation as well.

Setting Up: The buyer must set up the foundation and soil gradation for the tanks. Manufacturers usually check all the specs before installation and get them fixed in case of problems. The installer will make sure that the grade is maintained and the area is free of debris. On-site welding is done using the best possible methods – arc welding, electro slag, or electro gas.

Inspection: Inspection is done using x-rays and vacuum testing of the floors to ensure that it is safe to use. The buyer must ensure that all local and federal regulations are met, along with the procurement of specialized permits. Owners must also have cleanup processes in place.

An important feature of these standards is that the buyer can review documentation to ensure conformity, as well as inspect manufacturing facilities. It helps fabricators and buyers protect their investment.