API 650 – THIRTEENTH Edition – Welded Tanks for Oil Storage

API 650, also known as the “Welded Tanks for Oil Storage” standard, is an American Petroleum Institute (API) specification that outlines the minimum requirements for the design, fabrication, erection, and inspection of welded storage tanks used in the oil and natural gas industry.

Scope: API 650 is applicable to welded tanks used for the storage of petroleum products, including crude oil, gasoline, and various chemicals. The standard covers both aboveground and underground tanks, providing specifications for their construction and maintenance.

Key Features:

Tank Types: API 650 applies to various types of tanks, such as cone roof tanks, floating roof tanks, and flat-bottom tanks. It accommodates different designs based on the specific requirements of the stored material and environmental conditions.
Materials: The standard specifies the materials to be used in tank construction, addressing the types of steel, welding processes, and other components necessary to ensure the tank’s structural integrity and longevity.
Design Requirements: API 650 outlines the design criteria for tanks, covering factors like shell thickness, roof and floor design, seismic design considerations, and wind loads. The goal is to ensure the tanks can withstand the conditions they may encounter during their operational life.
Fabrication and Welding: The standard provides guidelines for the fabrication and welding processes, including inspection and testing procedures. This ensures the quality of construction, and it emphasizes the importance of qualified personnel involved in these processes.
Erection and Inspection: API 650 specifies requirements for the proper erection of tanks, including foundation design and construction. Additionally, it outlines inspection and testing protocols to verify the integrity of the tank before it is put into service.
Corrosion Protection: The standard addresses methods for protecting tanks against corrosion, which is a critical consideration given the nature of the materials stored and the potential environmental impact of leaks or failures.

Industry Application: API 650 is widely adopted in the oil and gas industry and is a key reference for engineers, manufacturers, and inspectors involved in the design, construction, and maintenance of storage tanks. Compliance with API 650 is often required by regulatory bodies and serves as a benchmark for ensuring the safety and reliability of storage tank facilities.