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BRIEFLY ABOUT DESIGN CALCULATIONS

 

 Storage tank design calculation services involve detailed engineering to ensure that the tank meets the requirements set by the design code for aboveground storage tanks, typically used for liquid storage. These calculations cover various components and loadings to ensure the tank's structural integrity and safety. Key aspects of the design include:

  1. Shell Design: shell thickness calculations as per design code.

    1. Divide Shell into Courses: The height of the tank is divided into multiple shell courses, each with a specific thickness

    2. Design for Hydrostatic Test: Ensure the shell thickness can withstand the hydrostatic test pressure

    3. Consider Environmental Conditions: Account for factors such as wind load, seismic load, and temperature variations.

    4. These calculations ensure that the tank shell is structurally sound and can safely contain the stored liquid under various conditions.

  2. Bottom Design: bottom & annular thickness calculations as per design code.  Calculation of the bottom plate thickness ensures it can support the weight of the stored liquid and resist settlement or deformation.

  3. Roof Design: The roof, whether fixed or floating, is designed to withstand internal pressure, wind loads, and external environmental factors. Floating roofs require calculations for buoyancy and stability under varying liquid levels.

  4. Wind Forces: Wind load calculations are critical to ensure the tank’s stability under high wind conditions. Wind girders or stiffners are often required to prevent buckling or structural failure due to lateral forces.

  5. Seismic Forces: Tanks must be designed to resist seismic forces, which vary based on location. Seismic calculations account for tank size, location, and ground conditions to ensure stability during an earthquake.

  6. Internal Pressure:  Internal pressure calculations are performed to ensure the tank can withstand operational pressures without risk of failure.

  7. External Pressure: For tanks subjected to external pressure (e.g., for vacuum conditions or external loading), the design ensures the structure can resist collapse or deformation.

  8. Wind Girders: In tanks with large diameters, wind girders or additional structural reinforcements are designed to provide lateral support and prevent structural damage due to wind forces.

  9. The need for tank anchorage is determined through detailed calculations, which assess the structural requirements based on the tank’s design, size, location, and the forces it will experience during operation. Anchorage is typically required to prevent the tank from floating or shifting due to external forces like wind, seismic activity, or fluctuating liquid levels.

These calculations ensure that the tank is safe, stable, and compliant with design standards, providing long-term reliability in liquid storage operations.

 

CODES & STANDARDS

 

API 650: Welded Steel Tanks for Oil Storage


This is the most widely used standard for designing and constructing above-ground storage tanks made of carbon steel for the storage of petroleum and other liquids.

API 620: Design and Construction of Large, Welded, Low-Pressure Storage Tanks.

 

This standard applies to tanks designed to store liquids at pressures up to 2.5 psi (pounds per square inch) and is often used for tanks with larger capacities.

UL 142: Steel Aboveground Tanks for Flammable and Combustible Liquids


This standard covers the design and construction of steel tanks used for the storage of flammable and combustible liquids in above-ground installations.

NFPA 30: Flammable and Combustible Liquids Code


This standard from the National Fire Protection Association (NFPA) provides guidelines for the safe storage of flammable and combustible liquids, including the design of storage tanks.

API 1615: Design, Construction, and Installation of Underground Storage Tanks (USTs)


This standard provides guidelines for the installation and maintenance of steel underground storage tanks for petroleum products.

UL 58: Steel Underground Tanks for Flammable and Combustible Liquids


This standard is widely used for steel tanks that are intended for underground storage of petroleum and other liquids.

BS EN 12285-1: Steel Tanks for the Storage of Liquid Petroleum Products


This standard, part of the European EN standards (adopted by the UK), covers the design and construction of welded steel tanks for the storage of petroleum products. It provides guidelines for above-ground steel tanks.

BS 2594: Design and Construction of Steel Tanks for the Storage of Petroleum Products


This British Standard outlines the design, construction, and installation of steel storage tanks specifically for the storage of petroleum products. It has been largely superseded by more recent European standards, but it remains a reference in some areas.

BS EN 14015: Specification for the Design and Manufacture of Site Built, Vertical, Cylindrical, Flat-Bottomed, Welded Steel Tanks for the Storage of Petroleum Products


This European Standard (adopted in the UK) is specifically relevant to the construction and safety of above-ground, vertical steel tanks for petroleum storage.

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