What is a Storage Tank? Functions, Materials, and Safety


Storage tanks are essential components widely used across various industries for the safe and efficient storage of a multitude of substances, including liquids, gasses, and solids. Predominantly found in sectors such as oil and gas, chemical processing, water treatment, and agriculture, these tanks play a crucial role in maintaining the continuity of industrial operations. They are designed to hold materials under specific conditions—whether at atmospheric pressure, under a controlled temperature, or within certain chemical environments—to ensure that these materials are available in sufficient quantity and maintained quality when required. This comprehensive article delves into the core aspects of storage tanks, covering their functions, types, materials, safety considerations, and guidelines for selecting the right tank.

What is a Storage Tank?

Cryogenic Liquid Vacuum Storage Tank

A storage tank is a container, typically large, used to store various types of liquids, gasses, and sometimes solids. These tanks can be found in many different industries such as oil and gas, chemical manufacturing, water supply, and agriculture. Their primary purpose is to hold a substantial amount of material in a controlled environment — be it under pressure, at a specific temperature, or within certain chemical conditions — to ensure that these materials are available in sufficient quantity and appropriate quality when needed.

The Key Functions of Storage Tanks

Storage tanks serve multiple critical functions:

  1. Storage and Conservation: They provide a way to hold large volumes of material until needed, reducing losses that might occur through evaporation or spillage. This allows for efficient inventory management, ensuring a steady supply of materials for ongoing operations without shortages.
  2. Mixing and Blending: Certain tanks are designed for mixing or blending different liquids or gasses to create specific formulations.
  3. Transportation: Portable storage tanks are used to transport liquids or gasses over short distances.
  4. Safety and Compliance: Proper storage of hazardous materials helps in complying with safety and environmental regulations.
  5. Buffering: Tanks can act as buffers between the production and the consumption rates, smoothing out fluctuations in demand and supply.

Types of Storage Tanks

In various industries like oil and gas, petrochemicals, water treatment, and food processing, storage tanks play a vital role in securely storing substances. These tanks come in different types, each tailored to specific storage needs. Here is a more detailed overview of the various types of storage tanks:

  1. Fixed Roof Tanks: These tanks have a stationary roof, often cone or dome-shaped, and are designed for storing liquids with low vapor pressures. They are commonly used for storing crude oil, refined petroleum products, and water.
  2. Floating Roof Tanks: Equipped with a floating roof that adjusts with the liquid level, reducing vapor space and evaporation losses. There are two types of floating tanks which are External Floating Roof Tank (EFR) and Internal Floating Roof Tank (IFR). They are suitable for liquids with higher vapor pressures like gasoline and diesel fuel.
  3. Horizontal Tanks: Tanks oriented horizontally, ideal for storing liquids with low vapor pressures such as water and chemicals. They are space-efficient and commonly used when space is limited.
  4. Pressure Tanks (High-Pressure Vessels): Designed to store liquids or gasses at high pressures, typically cylindrical with a robust wall to withstand pressure. Widely used in industries like chemicals, petrochemicals, and power generation.
  5. Vertical Tanks: Tanks with a vertical orientation, are commonly used for storing liquids with low vapor pressures like water and chemicals. They are space-saving and preferred when the ground area is limited.
  6. LNG Tanks: Specialized tanks for storing liquefied natural gas at extremely low temperatures around -160°C. These tanks are often spherical or cylindrical, insulated to maintain low temperatures, and crucial in the natural gas industry for LNG storage and transportation.

Each type of storage tank serves specific purposes and must be selected based on factors like the stored substance’s characteristics, volume, pressure, temperature requirements, and safety considerations. Choosing the right tank is essential to ensure efficient and safe storage practices in various industries.

Materials of Storage Tanks

The choice of material for constructing storage tanks is crucial and depends on the chemical properties of the material to be stored, environmental conditions, cost considerations, and the desired lifespan of the tank:

  1. Steel: Widely used due to its durability and strength. Different steel grades offer varying levels of corrosion resistance based on the stored material. It can be coated or lined to prevent corrosion and is suitable for a wide range of temperatures and pressures.
  2. Concrete: Preferred for large tanks that store water, sewage, and certain chemicals. Concrete offers good structural integrity and fire resistance and it is advantageous in terms of cost for large volumes.
  3. Polyethylene and Fiberglass: These are used for chemically resistant tanks or water tanks in small to medium sizes, offering excellent resistance to corrosion. However, they may not be suitable for high-pressure applications.
  4. Stainless Steel: Used for tanks that store aggressive chemicals or food products due to its corrosion resistance and non-reactive properties compared to regular steel.

These materials offer different advantages and are chosen based on factors like the type of substance being stored, durability requirements, cost-effectiveness, and resistance to corrosion or chemical reactions.

Safety of Storage Tanks

Safety is a crucial aspect of storage tank management, particularly when storing hazardous or flammable materials like diesel fuel. Proper handling, storage, and maintenance of storage tanks are essential to prevent environmental damage, accidents, and fires.

  • Fire safety measures, including fire extinguishers, smoke detectors, and automatic fire suppression systems, should be implemented to prevent fires. Employees handling stored materials should be trained in safe handling, storage procedures, spill response, and emergency response. Regular training and safety meetings can reinforce safe practices and ensure employee awareness of risks associated with storage tanks.
  • Regular inspections and maintenance of storage tanks are essential to ensure that they are in good working order and to prevent leaks and spills. Businesses that handle bulk storage are required to maintain records of inspections, maintenance, and testing of the storage tank and associated equipment.
  • Leak detection and monitoring systems, such as automatic tank gauging systems or other electronic monitoring devices, should be in place to detect leaks or spills promptly. Secondary containment systems, such as a dike or spill containment basin, should also be in place to prevent spills and leaks from spreading beyond the containment area.
  • The storage of other hazardous materials, such as LPG, is also important. LPG storage tanks should be protected from unauthorized access to reduce the chance of intentional or accidental interference. The user of the LPG has responsibilities concerning the tank, including ensuring that it is maintained in a safe condition.

In sum, proper handling, storage, and maintenance of storage tanks, along with regular inspections and employee training, can help prevent accidents, spills, and fires. By following safety guidelines and regulations, businesses can ensure that their storage tanks are safe and compliant with local regulations, protecting their employees, equipment, and the environment from potential hazards.

Differences Between Pressure Vessels and Storage Tanks

While both pressure vessels and storage tanks are designed to hold substances under pressure, they serve different purposes, construction, orientation, mounting, material, size, cost, and heating method:

  • Pressure Vessels: Designed to operate at pressures significantly above atmospheric or high pressure and are typically cylindrical or spherical to evenly distribute stress. They are mechanically designed and equipped with provisions for the introduction or removal of heat from the container. Pressure vessels are generally smaller in size and more expensive than storage tanks, as they have to contain higher pressure and temperature.
  • Storage Tanks: Primarily used for storing substances at or close to atmospheric or low pressure in a variety of shapes and sizes, depending on the application. They are usually made from thin-walled materials so they don’t hold as much pressure as pressure vessels. Storage tanks are larger in size, as they have to store larger volumes of fluid at lower pressure and temperature. However, they are less expensive than pressure vessels as they require less material, labor, and quality control to ensure their functionality and durability.

How to Choose the Right Storage Tank

When selecting the appropriate storage tank, it is essential to consider several critical factors to ensure optimal functionality and safety. Here are key considerations to guide you in choosing the right storage tank:

  1. Capacity: Determine the required storage capacity to avoid investing in a tank that is either too large or too small for your needs. This ensures efficient storage without unnecessary costs or limitations.
  2. Material Selection: Choose the tank material carefully based on factors like durability, corrosion resistance, and compatibility with the stored substance. Common materials include steel, aluminum, polyethylene, and fiberglass, each offering specific advantages for different applications.
  3. Compliance with Regulations: Ensure the selected tank meets all relevant safety and environmental regulations and codes to prevent potential hazards and ensure legal compliance in your area.
  4. Safety Features: Prioritize safety by selecting a tank that adheres to safety standards and regulations, reducing the risk of accidents, leaks, and environmental damage associated with improper storage practices.
  5. Type of Tank: Consider the various types of tanks available, such as above-ground, underground, portable, ground storage, elevated, and standpipe tanks, to choose the most suitable option for your specific storage requirements and site conditions.
  6. Cost Consideration: Factor in the price of the tank within your budget while ensuring it meets your quality and functional needs, balancing cost-effectiveness with performance.
  7. Size Alignment: Select the tank size based on available space and storage needs to ensure it fits your site and accommodates the required volume of the stored substance effectively.
  8. Availability and Suitability: Be patient in your selection process to find the right tank model that aligns with your budget and requirements, ensuring it is readily available and suited to your specific needs.

By carefully evaluating these factors and seeking expert advice when needed, you can confidently choose the right storage tank that meets your operational needs, safety requirements, and regulatory standards effectively.


Storage tanks are critical components across industries, each designed to meet specific storage needs. Understanding the types of tanks, materials used in their construction, safety measures, and the differences from pressure vessels can guide one in choosing the right tank for their needs. With proper selection, design, and maintenance, storage tanks can provide safe and efficient storage solutions for a wide range of substances.