What is API 620 standard?

If you are involved in the field of engineering, especially in the design and construction of aboveground storage tanks, then you must be familiar with API 620. API 620 is a widely recognized standard developed by the American Petroleum Institute (API) that specifies the requirements for designing and constructing large steel tanks used for storing liquids at atmospheric pressure or higher.

Scope and Application

The API 620 standard applies to the design and construction of large, welded, low-pressure storage tanks that have a maximum operating temperature of 93°C (200°F) or lower. It covers tanks with diameters ranging from 15 ft to 300 ft and capacities exceeding 75,000 gallons. This standard is applicable to tanks storing oil, petroleum products, water, chemicals, and other liquids with specific properties.

Key Requirements

To ensure safety and integrity, API 620 sets out several key requirements for tank design, materials, fabrication, inspection, and testing. These include:

Design considerations: The standard provides guidelines for calculating loads such as wind, seismic, internal pressure, and external pressure. It also addresses requirements for the design of roofs, bottoms, and shell reinforcement.

Material selection: API 620 specifies the minimum mechanical properties, chemical composition, and identification marking for steel plates, sheets, and bars used in tank construction. It also outlines the requirements for corrosion protection.

Fabrication and welding: The standard covers welding procedures, qualifications, and inspection methods. It highlights the importance of proper welding techniques to prevent defects and ensure the structural integrity of the tank.

Inspection and testing: API 620 mandates various non-destructive examination techniques, such as radiographic, ultrasonic, and magnetic particle testing. It also requires hydrostatic testing to validate the tank's strength and integrity.

Compliance and Benefits

Compliance with API 620 not only ensures the safety of storage tanks but also provides several benefits:

Confidence in design: Following this standard instills confidence in the tank's structural design and integrity, providing assurance that it can safely handle the intended contents and withstand external forces.

Industry recognition: API 620 is widely recognized in the oil and gas industry, facilitating collaboration and adherence to a common set of standards. Adhering to API 620 can enhance credibility and trust among stakeholders.

Regulatory compliance: Many jurisdictions require compliance with API standards, including API 620, for tank construction and operation. Complying with these regulations helps organizations avoid legal issues and penalties.

Operational reliability: Tanks designed and constructed according to API 620 are less prone to structural failures, leaks, and environmental hazards, resulting in improved operational reliability and minimized downtime.

In conclusion, API 620 plays a crucial role in ensuring the safe design and construction of large aboveground storage tanks. Its comprehensive requirements address various aspects of tank design, materials, fabrication, inspection, and testing. Adhering to this standard not only ensures compliance with industry regulations but also promotes safety, reliability, and confidence in tank operations.