Floating Roof Tank: Components, Types, & Industrial Benefits

Floating roof tanks are a key solution in the industrial sector for managing liquid storage efficiently, safely, and in an environmentally friendly manner.

These tanks are widely used in the oil, petrochemical, and chemical industries due to their ability to reduce evaporation and maintain product quality.

With their innovative design, floating roof tanks can adapt to the volume of stored liquid, thereby providing numerous operational benefits for companies.

So, what are the components and types of floating roof tanks commonly used in the industrial sector? Let’s explore below.

What Is a Floating Roof Tank?

A floating roof tank is a storage tank equipped with a floating roof that rises and falls with the liquid level inside. This type of tank is generally used to store volatile liquids such as gasoline, jet fuel, crude oil, diesel, and other light petroleum products.

The roof floats directly on the liquid’s surface, leaving almost no vapor space inside the tank. The floating roof seals the liquid surface directly, reducing evaporation by over 90%.

However, the extent of emission reduction can vary with operational conditions, including ambient temperature, liquid volatility, seal condition, and liquid level changes.

A floating roof tank system operates passively. Thus, as the liquid volume increases or decreases with filling or emptying, the roof automatically moves up or down. This ensures the tank remains tightly sealed and minimizes the release of hazardous vapors into the air.

Additionally, the use of floating roof storage tanks helps reduce the risk of fire and explosion by preventing the formation of flammable vapor-air mixtures.

Components of a Floating Roof Tank

Generally, a floating roof tank consists of two main components, namely:

Floating Roof. This part is the most important element because it covers the liquid surface and moves in accordance with the tank’s fill level.
Seal. Located between the roof and the tank wall. Its function is to ensure there are no gaps that allow vapor or liquid to escape from the tank.

This seal functions like a flexible tube that remains in contact with the tank wall as the roof moves. To enhance safety and efficiency, two layers of seals are typically used: a primary seal and a secondary seal. This additional layer significantly reduces gas and vapor emissions while protecting the environment.

Types of Floating Roof Tanks

There are two main types of floating roof tank designs commonly used in the industry:

1. Internal Floating Roof Tank (IFRT)

An internal floating roof tank has a fixed roof on the outside, typically a dome or cone, and a floating roof on the inside.

This design provides extra protection against weather conditions such as rain, wind, or extreme heat. With the outer roof, the floating roof inside the tank is not directly exposed to the external environment.

The main advantages of IFRTs are as follows:

More effectively reduces evaporation (vapor space).
Reduces the risk of air pollution.
Provides additional protection for the product.
Minimizes the risk of fire.

Additionally, the gas layer in the vapor space functions as thermal insulation, helping maintain a stable liquid temperature. IFRTs are often equipped with modern monitoring systems to ensure optimal performance and regulatory compliance.

In addition to these advantages, IFRTs have several drawbacks that also should be considered. Here are some of them:

Maintenance costs are higher than those of EFRTs.
The design is more complex compared to EFRT.
Routine maintenance of the floating roof is required to keep it watertight.
Periodic inspection of the pontoon is required.

2. External Floating Roof Tank (EFRT)

An external floating roof tank is an open-top tank with a floating roof that sits directly on the liquid surface, with no additional protection on top.

This tank features an open cylindrical structure with a single or double-deck floating roof. A perimeter sealing system is used to prevent evaporation and the ingress of contaminants. The advantages of the EFRT include:

A simpler design.
Lower construction costs than the IFRT.
Effectiveness for large-scale storage of volatile liquids.

The seal on the EFRT plays a crucial role in maintaining product quality and reducing losses due to evaporation. Additionally, the EFRT design helps prevent the entry of dust, water, or other particles that could contaminate the tank’s contents.

However, it is also important to note that the EFRT has several drawbacks, including:

Greater susceptibility to fire and explosions compared to the IFRT because the floating roof does not provide sufficient protection against ignition sources.
The floating roof is also susceptible to damage from other factors, such as strong winds and heavy loads from rainwater or snow, which can lead to leaks and spills.

Benefits of Floating Roof Tanks

The use of floating roof tanks offers significant benefits for industries, particularly those in the chemical and petrochemical sectors. One of the most important is the efficient reduction of vapor emissions.

Floating roof tanks are a cost-effective and efficient solution for reducing vapor emissions and product loss (evaporative losses) during storage.

Vapor emissions refer to the release of vapor or chemical gases, particularly Volatile Organic Compounds (VOCs), which are primarily generated by industrial activities such as oil refineries and fuel storage tanks.

According to a study titled “Environmental and Health Risk Assessments of Volatile Organic Compounds (VOCs) Based on Source Apportionment,” published in the journal Toxics (2025), these compounds are highly volatile and hazardous.

It is noted that VOCs can cause serious health issues, such as cancer, respiratory problems, and damage to the nervous system.

Additionally, VOCs contribute to air pollution by forming tropospheric ozone and other harmful particles.

Globally, VOC emission levels remain high and are a serious concern, particularly in industrial areas.

Therefore, the use of technologies such as floating roof tanks, Vapor Recovery Units (VRUs), and closed systems is a crucial step toward reducing emissions while improving operational efficiency. Furthermore, there are several other benefits of floating roof tanks, namely:

Storage Capacity Flexibility. These tanks can automatically adjust their storage capacity based on liquid volume, making them more efficient in space utilization.
Environmental Compliance. These tanks help companies meet environmental regulations by reducing emissions of hazardous gases into the atmosphere.
Protection from Weather and Contamination. Floating roof tanks protect the tank contents from rain, dust, and other environmental factors that can compromise product quality.
Enhanced Safety. By minimizing the vapor space, the risk of fire and explosion is significantly lower than with conventional tanks.
Extended Product Shelf Life. Stored products remain stable and are less prone to oxidation, resulting in a longer shelf life.
Operational Reliability. These tanks support sustainable industrial operations with a low risk of product loss.
Application Flexibility. Floating roof tanks can be used for various types of liquids, making them suitable for specific sectors, such as:
- The oil and gas industry.
- Refineries and petrochemicals.
- Fuel storage and distribution terminals.

Differences Between Floating Roof Tanks and Fixed Roof Tanks

A fixed roof tank is a tank with a stationary roof. Unlike a floating roof tank, this tank has a vapor space between the liquid and the roof. Here are the main differences between the two:

Design: A floating roof tank has a movable roof, whereas a fixed roof tank has a stationary roof.
Emissions: Floating roof tanks are more effective at reducing evaporation.
Safety: Floating roof tanks are safer for volatile liquids.
Cost: Fixed roof tanks are cheaper to construct and maintain.
Applications: Fixed roof tanks are suitable for non-volatile liquids such as water or heavy oil.

The selection of tank types depends heavily on the characteristics of the stored liquids and the company’s operational needs.

Port and Storage Services from Chandra Daya Investasi

As part of its commitment to supporting the petrochemical industry, the Chandra Daya Investasi (CDI) Group, through PT Redeco Petrolin Utama, provides integrated, reliable port and storage services as a professional, efficient solution for bulk liquid storage.

RPU has been operating in Banten since 1986 and is recognized as a leading player in the management of chemical and petrochemical storage tanks. With comprehensive facilities, RPU offers:

2 docks, each with a LOA of 200 meters, capable of accommodating vessels up to 35,000 DWT and a draft of 10 meters.
72 storage tanks with a total capacity of 130,000 m³.
A centralized fueling system (CFS).
A digital customer service system (COS).
High safety standards, including an oil spill containment system using oil booms.

All operations are conducted in accordance with international standards and ISO certification, ensuring safety, quality, and environmental sustainability.

In response to the growing industry needs in Indonesia, RPU continues to provide flexible, efficient, and reliable logistics and storage solutions.

If you are looking for a reliable partner for chemical and petrochemical storage, PT Redeco Petrolin Utama and Chandra Daya Investasi are ready to be #YourGrowthPartner to support your business growth.