Types of Industrial Storage Tanks: A Complete Guide to Storage Tank Types and Applications

Types of Industrial Storage Tanks Manufactured in India

Storage tanks are among the most common pieces of equipment on any industrial site, yet the right tank type, orientation, and material of construction depend entirely on what is being stored, how much space is available, and what regulations apply to that specific liquid or chemical. A tank built for treated water storage is not interchangeable with one built for diesel, hazardous chemicals, or a corrosive process fluid, even if the two look similar from the outside.

Industrial storage tanks are generally classified by orientation, vertical, horizontal, or underground, and then specified further by material of construction and design standard based on the substance being stored. This guide covers each orientation, the materials typically used, and the applications each configuration is built for, so you can specify the right tank before requesting a quote.

Vertical Storage Tanks

Vertical storage tanks stand upright on a flat base and are the most space-efficient configuration for large storage volumes, since they maximize storage capacity per unit of ground area. This makes them the standard choice for facilities with limited floor space but adequate ceiling or outdoor height clearance.

Vertical tanks are typically supported on a concrete ring foundation or a structural steel base, and are fitted with a flat, conical, or domed roof depending on whether the tank is open to atmosphere, vented, or fully sealed. Larger vertical tanks, particularly those built to API 650 standards, are common for bulk storage of water, fuel, and process chemicals at refineries, water treatment plants, and chemical manufacturing sites.

Because a vertical tank's full liquid column exerts pressure on the base and lower shell courses, tank wall thickness is not uniform from top to bottom. The lower courses are built thicker than the upper courses to handle the greater hydrostatic pressure at the base, a detail that distinguishes a properly engineered vertical tank from a simple uniform-wall cylinder.

Horizontal Storage Tanks

Horizontal storage tanks lie on their side, supported by two or more saddle supports along their length. This configuration suits sites where ground footprint is less constrained than height, such as tank farms, fuel depots, and process areas with low headroom, and is also easier to transport as a complete pre-fabricated unit since it can be shipped horizontally on a standard trailer.

Horizontal tanks are commonly used for smaller to medium storage volumes compared with vertical tanks of the same site footprint, and are the standard configuration for above-ground diesel and fuel storage, compressed air receiver tanks, and process buffer tanks where a lower profile is preferred for accessibility or wind loading considerations. Nozzle placement on a horizontal tank is also more flexible along the shell length, which can simplify piping layout compared with a tall vertical tank.

Underground Storage Tanks

For applications requiring concealed storage or protection from environmental exposure, underground tanks provide a secure solution. Built from MS IS2062, SS304 or SS316, or coated mild steel depending on the stored substance, these tanks are designed to prevent contamination of the stored liquid, resist external soil pressure and groundwater loading, and support long-term storage without surface footprint.

Underground tanks require additional engineering considerations that above-ground tanks do not, including external corrosion protection through coatings or cathodic protection systems, structural design to handle soil load and any vehicle traffic loading above the tank, and leak detection provisions since a leak underground is far harder to detect and contain than one on an above-ground tank in plain view. Regulatory requirements for underground fuel and chemical storage are also typically stricter, given the higher environmental risk if containment fails.

Underground tanks are specified for fuel storage covering petrol, diesel, and aviation fuel at depots and airports, chemical tanks for hazardous liquids where surface storage is restricted by site layout or safety codes, and potable water storage for industrial facilities where protecting water quality from temperature swings and surface contamination is a priority.

Material of Construction

Storage tank material is selected based on what the tank will hold, not on the orientation of the tank itself, since the same vertical, horizontal, or underground configuration can be built in any of the following materials depending on the application.

• MS IS2062: mild steel conforming to IS2062, the standard structural steel grade for water storage, fuel storage, and general industrial liquids that are not significantly corrosive

• SS304 / SS316: stainless steel grades specified for potable water, food and beverage storage, and mildly corrosive chemicals where product purity and corrosion resistance both matter

• Coated mild steel: mild steel with an internal or external protective coating, used to extend service life in moderately corrosive service at a lower cost than stainless steel

For underground tanks specifically, the choice between these materials also affects the external protection strategy. A coated mild steel underground tank typically requires cathodic protection in addition to the coating to fully prevent soil-side corrosion, while stainless steel underground tanks rely primarily on the inherent corrosion resistance of the material itself.

Design Standards and Wall Thickness

Storage tank design in India commonly follows IS 803 for vertical tanks used in oil storage, or is engineered to API 650 for larger bulk storage applications, particularly where a client's design basis specifically calls for it. These standards define minimum wall thickness by shell course based on tank diameter, liquid specific gravity, and fill height, along with requirements for nozzle reinforcement, roof design, and foundation interface.

Wall thickness calculations also include a corrosion allowance, additional material thickness beyond what is structurally required, to account for gradual wall thinning over the tank's service life due to the stored liquid or atmospheric exposure. Skipping or under-specifying a corrosion allowance is one of the more common ways an underspecified tank fails to reach its expected service life, particularly for underground tanks where inspection and early detection of thinning is harder to perform.

Tank Accessories and Fittings

Beyond the shell and roof, a functional storage tank installation depends on the accessories specified alongside it. Manways provide access for inspection and cleaning and are sized to allow a person to enter safely for maintenance. Vents, either open vents or pressure-vacuum relief valves, prevent a sealed tank from developing a vacuum as liquid is drawn out or overpressure as it is filled, both of which can deform or rupture a tank wall not designed to handle that pressure differential.

Level gauges, ranging from simple sight glasses to radar or ultrasonic level transmitters, let operators monitor tank contents without opening the tank, which matters both for operational efficiency and for safety when the stored liquid is hazardous. Overfill protection systems, required by code for many fuel and chemical storage applications, shut off filling automatically before the tank reaches capacity, reducing the risk of spillage during transfer operations. Specifying these accessories alongside the tank itself, rather than as an afterthought, avoids retrofitting work once the tank is already installed and in service.

Choosing Between Vertical, Horizontal, and Underground

Factor	Vertical Tank	Horizontal Tank	Underground Tank
Ground footprint	Smallest for a given volume	Larger footprint than vertical	No surface footprint
Typical volume range	Large bulk storage	Small to medium volumes	Small to medium volumes
Installation complexity	Requires ring foundation	Simple saddle supports	Requires excavation, soil engineering
Inspection access	Easy, fully visible	Easy, fully visible	Limited, requires leak detection systems
Common use	Bulk water, fuel, chemical storage	Fuel depots, air receivers, buffer tanks	Fuel storage, hazardous liquids, potable water

The decision typically starts with available space. If ground footprint is limited and height clearance is available, a vertical tank makes the most efficient use of the site. If footprint is not the constraint but headroom or wind exposure is, a horizontal tank is usually more practical. If the application specifically requires concealment, protection from environmental exposure, or the site layout does not allow above-ground storage at all, an underground tank is the only option regardless of the volume involved.

Frequently Asked Questions

What is the difference between IS 803 and API 650?

IS 803 is the Indian standard for vertical, cylindrical, welded steel oil storage tanks, while API 650 is the American Petroleum Institute standard for welded steel tanks used in the oil and chemical industry. Both cover similar design principles, shell thickness by course, foundation interface, and nozzle reinforcement, but API 650 is more commonly specified by multinational clients or where a project's design basis explicitly calls for it.

How is corrosion allowance decided for a given application?

Corrosion allowance depends on the corrosivity of the stored liquid, the tank material, and the expected service life. A tank storing treated water in stainless steel may need a minimal allowance, while a mild steel tank storing a mildly corrosive chemical over a twenty year design life will need a more significant allowance built into the wall thickness calculation from the start.

Can an underground tank be converted to above-ground use later?

Not typically without significant modification. Underground tanks are designed for soil load and external pressure rather than wind and seismic loading that above-ground installation requires, and they are usually not fitted with the support saddles or foundation interface an above-ground tank needs. It is more practical to specify the correct installation type from the outset.

Why Choose Rudraksh Steel

Rudraksh Steel Private Limited manufactures vertical, horizontal, and underground storage tanks in MS IS2062, SS304, SS316, and coated mild steel, engineered to IS 803 or API 650 as the application requires. Each tank is designed around the client's stored substance, required capacity, and site constraints, with wall thickness and corrosion allowance calculated for the specific service rather than supplied as a generic catalog unit.

Conclusion

Choosing between a vertical, horizontal, or underground storage tank comes down to available site footprint, the volume you need to store, and whether the application specifically requires concealed or protected storage. Material selection then follows from what the tank will hold, balancing corrosion resistance against cost. Sharing your site layout, stored substance, and required capacity with your manufacturer at the enquiry stage is the most reliable way to arrive at a tank specification that will perform for its full design life.