Storage tanks, abbreviated as TK, are containers used to store liquids, gases, or solids for various purposes, such as in industrial processes, commercial or residential use, or for transportation.  They come in a variety of shapes, sizes, and materials depending on the specific requirements of the application.  Storage tanks can be made from a wide range of materials, including steel, aluminum, fiberglass, and plastic.  They can be designed to hold various types of liquids, such as water, oil, chemicals, and fuels, and can be equipped with a variety of features, such as vents, pumps, and level gauges, depending on the intended use.

• See Article  -  Storage Tank Glossary
• Tags: Storage Tank and Pressure Vessel ASME Standards API Standards Abbreviations Stationary Equipment Glossary

Storage Tank Index

• Storage Tank Design Classification
• Storage Tank Uses
• Storage Tank Corrosion
• Storage Tank Standards
• Storage Tank Abbreviations

Some common types of storage tanks

• Above-ground storage tanks (AST)  -  These are tanks that are located on the ground, typically in a vertical or horizontal configuration.
• Underground storage tanks (UST)  -  These are tanks that are buried underground, often used for storing petroleum products or hazardous chemicals.
• Portable storage tanks (PST)  -  These are tanks that can be moved from one location to another, often used for transportation of liquids or gases.

Storage tanks play a critical role in many industries and applications, such as in the energy, chemical, and food processing industries.  They must be designed, installed, and maintained properly to ensure safety and environmental protection.

Storage Tank Design Classification

• Horizontal Tank (double wall and single wall)  -  A cylindrical steel tank with flat or dished end operating at atmospheric conditions or at pressure and provided with suitable support saddles intended for aboveground storage of non-corrosive, stable, flammable and combustible liquids.
  
  • Single Skin Oil Tank  -  The body of the horizontal tank consists of cylindrical and end wall parts.  The cylindrical part is called a wall and the ends called  bottoms.  These tanks are used to store non-aggressive and environmentally frendly liquids.
  • Double Skin Oil Tank  -  A special vessel with two shells and a free space between them.  The interspace, the area between two shells, is filled with antifreeze or gaseous nitrogen.  The thickness of this tank ensures oil, oil products, and hazardoud chemical products will not leak into the environment.
  • LPG Storage Tank (Bullet Tank)  -  A specialized type of storage tank used for the storage of Liquefied Natural Gas.  LNG Storage tanks have the ability to store LNG at the very low temperature of -162°C.  LNG storage tanks have double containers, where the inner contains LNG and the outer container contains insulation materials.
• Rectangular Tank  -  This tank can be used to store dry or liquid materials. The main advantage of rectangular tanks is that they can be stacked on top of each other to save space.

• Spherical Tank  -  These tanks are a closed container designed to hold gas or liquid at a significantly different pressure with the external environment.

• Vertical Tank (bolted and welded) (double wall and single wall)  -  Vertical storage tanks are most frequently used for bulk storage of water, fertilizer, agricultural and industrial chemicals.
  
  • Open Top Tank (atmospheric)  -  Normally for petroleum products but can contain cooling water and fire water.
  • Fixed Roof Tank (atmospheric, low pressure, high pressure)  -  Can either be self supported or rafter/trusses supported depending on the size of this non moving roof.  They have a solid top that is attached directly to the shell. Depending on age and design, these tanks may or may not be vapor and liquid tight.  These tanks meet the minimum requirements for storing most liquids and are the cheapest to construct.
    
    • Cone Roof Tank (supported and self supported)
    • Dome Roof Tank (supported and self supported)
    • Internal Floating Roof Tank (supported and self supported)
  • Floating Roof Tank  -  Roof sits directly on top of product.  These tanks are designed to reduce vapor emissions and volume inside of the tank. This is achieved with the roof floating on the surface of the liquid inside the vessel.  The roof raises and lowers with the liquid level, preventing a buildup of vapor inside.
    
    • External Floating Roof Tank  -  The roof floats directly on top of the product or on pontoons at the liquid level.  The tank is open to the atmosphere.
      • Double-type Floating Roof Tank
      • Pan-type Floating Roof Tank
      • Pontoon-type Floating Roof Tank
    • Internal Floating Roof Tank  -  This tank has two roofs.  The floating roof is the internal component, floating on the liquid.  Above it, there is a fixed roof at the top of the storage vessel.

Storage Tank Corrosion

Corrosion in metals is a natural phenomenon.  Unless protective measures are taken, above and below metal tanks, piping, and other metal components of the storage systems corrode and eventually leak product into the environment.  All corrosion protection systems must be operated and maintained to continuously provide corrosion protection to the metal components of the tank and piping that come in contact with the ground.

Storage Tank Standards

API Standards

• API Std 620 - Standard for Design and Construction of Large, welded, Low-pressure Storage Tanks
• API Std 650 - Standard for Welded Steel Tanks for Oil Storage
• API RP 651 - Recommended Practice for Cathodic Protection of Aboveground Storage Tanks
• API RP 652 - Recommended Practice for Cathodic Protection of Aboveground Storage Tanks
• API Std 653 - Standard for Tank Inspection, Repair, Alteration, and Reconstruction
• API Std 2000 - Standard for Venting Atmospheric and Low-pressure Storage Tanks: Nonrefrigerated and Refrigerated
• API Std 2015 - Standard for Requirements for Safe Entry and Cleaning of Petroleum Storage Tanks

NACE Standards

• NACE RP0193 - External Cathodic Protection of On-grade Metallic Storage Tank Bottoms
• NACE SP0102 - In-Line Inspection of Pipelines
• NACE SP0106 - Control of Internal Corrosion in Steel Pipelines and Piping Systems
• NACE SP0169 - Control of External Corrosion on Underground or Submerged Metallic Piping Systems
• NACE SP0188 - Discontinuity (Holiday) Testing of Protective Coating
• NACE SP0193 - External Cathodic Protection of On-Grade Carbon Steel Storage Tank Bottoms
• NACE SP0216 - Steel-Cased Pipeline Practices
• NACE SP0205 - External Corrosion Control of Underground Storage Tank Systems by Cathodic Protection
• NACE SP0285 - Corrosion Control of Underground Storage Tank Systems by Cathodic Protection
• NACE SP0502 - Pipeline External Corrosion Direct Assessment Methodology
• NACE SP0607 - Petroleum and Natural Gas Industries Cathodic Protection of Pipeline
• NACE Publication 51317 - Performance Failure of API 650 Oil Storage Tank Bottom Plates Due to Soil Side Corrosion
• NACE Publication 51318-11258 - Robotic Online Storage Tank Floor Inspection Case Study
• NACE Publication 51318 - Linings of Aboveground Storage Tanks
• NACE Publication 1E100 - Engineering Symbols Related to Cathodic Protection
• NACE TR21447 - Consequences of Coating Failures as Related to Interaction with Cathodic Protection