Self Bunded Tanks vs Single Wall Tanks: Which Is Right for Your Operation?

When it comes to storing and managing fuel safely and efficiently, choosing the right type of tank can make all the difference. At first glance, self bunded tanks and single wall tanks may seem similar; they both store fuel, diesel or other liquids but their structure, safety and compliance capabilities are worlds apart.

Whether you operate in construction, mining, agriculture or transport, understanding the differences between these two storage systems is vital to protecting your assets, your staff and the environment.

This guide explores everything you need to know about self bunded tanks vs single wall tanks, helping you decide which is the smarter, safer, and more cost-effective choice for your business.

What Is a Single Wall Tank?

A single wall tank sometimes referred to as a single-skin tank is the simplest form of fuel storage. It consists of a single steel wall or shell that holds the fuel or liquid inside.

Because it only has one barrier, any leak, puncture or overfill will immediately result in fuel escaping into the surrounding environment unless an external containment structure (a bund wall or spill pit) is in place.

Single wall tanks are often used in low-risk or temporary setups where an existing bunded area is already compliant. They’re lightweight, cheaper to manufacture and easier to transport. However, these benefits come with limitations, particularly in terms of compliance, safety and long-term costs.

What Is a Self Bunded Tank?

A self bunded tank also known as a double-walled or dual-skin tank is an advanced fuel storage system that includes two layers of protection. The inner tank holds the fuel, while the outer wall (or “bund”) acts as a built-in containment barrier.

This design means the tank effectively contains its own spill protection. If the inner tank leaks, the outer wall safely captures any escaped liquid, preventing contamination and environmental damage.

At Durotank, our self bunded fuel tanks are built to meet and exceed Australian Standards, including AS 1940:2017 and AS 1692, ensuring full compliance and peace of mind. With features such as overfill protection valves, anti-syphon devices and leak detection systems, they represent the gold standard in safe, reliable fuel storage.

Contact us for expert advice, a detailed quote or to explore customisation options tailored to your requirements.

Compliance and Environmental Protection

When storing fuel or other hazardous liquids, compliance with Australian safety and environmental standards isn’t optional, it’s essential.

Single Wall Tanks and Compliance

Single wall tanks can only meet compliance standards when installed within an external bund that holds at least 110% of the tank’s capacity. This usually means building a concrete bund wall or spill pit around the tank, complete with drainage and impermeable lining.

While this can satisfy the legal requirements, it adds considerable cost, time and maintenance responsibilities. Concrete bunds can crack, fill with rainwater or deteriorate over time, making compliance harder to maintain.

Self Bunded Tanks and Compliance

Self bunded tanks simplify compliance by incorporating the bund into the design itself. This built-in secondary containment means you don’t need to construct additional infrastructure or obtain separate engineering approvals for a bunded site.

At Durotank, our self bunded tanks are engineered to meet environmental protection standards straight out of the box, making them suitable for EPA-regulated industries, remote operations and high-volume fuel storage applications.

Safety and Risk Management

The Risks of Single Wall Tanks

With only one layer of protection, a single wall tank leaves little margin for error. A leak, corrosion point or accidental puncture can quickly escalate into a spill, potentially contaminating soil, groundwater or nearby waterways.

Even with an external bund, there’s still a higher risk of environmental exposure if the bund fails or overflows. Overfilling events are also more dangerous, as single wall systems often lack automatic overflow protection.

Why Self Bunded Tanks Are Safer

Self bunded tanks offer multiple levels of protection. The outer shell acts as a safety net, catching leaks before they cause damage. Many Durotank self bunded models come with built-in overfill alarms, giving operators real-time alerts if anything goes wrong.

This extra layer of protection not only safeguards the environment but also protects your business from costly cleanup, downtime, and potential fines.

When dealing with combustible liquids, fire risk is another crucial factor. Self bunded tanks often feature free to air vents, anti-syphon valves and secure fill points to prevent dangerous vapour build-up and unauthorised access offering a safer workplace overall.

Installation and Setup

Installing Single Wall Tanks

Installing a single wall tank is not as straightforward as it might seem. To meet compliance, you must construct a bunded area, complete with an impermeable base, drainage and spill monitoring systems.

These additional requirements can double or even triple installation time and cost. Site preparation also becomes more complex, as the bund and foundation must be engineered to handle spills, rainwater runoff and access for maintenance.

Installing Self Bunded Tanks

Self bunded tanks, on the other hand, are designed for quick and easy installation. Because the secondary containment is already integrated, there’s no need for extra civil works.

A self bunded tank can often be delivered, placed and filled on the same day, dramatically reducing project lead times. This makes them perfect for remote sites or businesses that need a plug-and-play solution.

To see examples of how simple setup can be, explore Durotank’s range of self bunded fuel tanks available in various sizes and configurations.

Cost Considerations

Initial Purchase

Single wall tanks have a lower upfront cost since they’re simpler to manufacture. For small operations or low-volume storage, this can make them appear more attractive initially.

However, once you factor in the cost of constructing and maintaining an external bund, installing drainage and achieving compliance certifications, that initial saving quickly disappears.

Lifetime Costs

Self bunded tanks require a higher initial investment, but their total cost of ownership is generally much lower. You save on civil works, compliance inspections and maintenance while reducing the risk of environmental damage and associated cleanup costs.

Durotank’s self bunded tanks are designed for long service life with minimal maintenance helping you achieve better ROI and greater operational efficiency over time.

Maintenance and Longevity

Maintaining a Single Wall Tank

A single wall tank requires frequent external inspections, especially of the bund area. You’ll need to regularly check for cracks, leaks, rainwater accumulation and corrosion. Cleaning and maintaining an external bund can be time-consuming, particularly in outdoor or dusty environments.

Maintaining a Self Bunded Tank

Self bunded tanks simplify maintenance. Because both containment layers are built together, you can use integrated leak detection systems to monitor performance easily.

The outer wall also provides added protection against weather exposure, UV damage and physical impacts, extending the tank’s lifespan. With proper care and periodic inspections, Durotank’s self bunded tanks can provide decades of safe, reliable service.

Our FREE Diesel Tank Inspection Checklist covers everything from structural integrity to fuel dispensing performance—helping you stay safe, compliant and operational.

Portability and Site Flexibility

Single Wall Tanks

While single wall tanks are lighter, they’re not particularly portable once installed because the bund is a fixed, site-specific structure. Moving them to a new location means rebuilding containment infrastructure from scratch.

Self Bunded Tanks

Self bunded tanks are engineered for mobility. Many Durotank models feature forklift pockets, lifting lugs and skid bases, allowing for easy relocation between worksites. This flexibility makes them ideal for industries like construction, mining and agriculture, where mobility and rapid deployment are key.

Space and Site Efficiency

External bund walls take up significant ground space and require clearance for safety and access. In smaller or more crowded sites, this can be a major disadvantage.

Self bunded tanks offer a compact footprint, combining both fuel storage and containment within a single unit. This space efficiency allows you to store more fuel safely within a smaller area, maximising operational capacity without expanding your site.

When a Single Wall Tank Might Be Enough

While self bunded tanks are the superior option in most situations, there are still cases where a single wall tank might be suitable:

• You already have a compliant external bund or containment system on site.
• You’re operating in a low-risk environment with small fuel volumes.
• You need a temporary storage solution with minimal upfront investment.
• You have strict weight limitations or limited mobility requirements.

Even so, it’s crucial to perform regular inspections and maintain your bund structure to remain compliant and environmentally responsible.

Why Self Bunded Tanks Are the Smarter Long-Term Choice

When all factors are considered safety, compliance, installation, cost and environmental protection self bunded tanks clearly outperform single wall tanks in almost every category.

They provide built-in containment, require minimal site preparation and meet modern regulatory standards with ease. For businesses that prioritise safety, efficiency and long-term savings, they represent the future of fuel storage.

With Durotank’s advanced designs, you gain not only superior protection but also convenience, durability and the flexibility to operate anywhere from city worksites to remote mining operations.

Key Advantages of Durotank Self Bunded Tanks

• Double-layered safety – Inner and outer walls provide automatic spill protection.
• Simplified compliance – Meets Australian Standards without additional bunding.
• Quick installation – Ready to use almost immediately after delivery.
• Reduced maintenance – No external bund to inspect or repair.
• High mobility – Easily transportable between locations.
• Environmentally responsible – Minimises risk of spills and contamination.

For more information about the design and safety features built into each Durotank system, explore our Complete Guide to Self Bunded Tanks.

Why Self Bunded Tanks Are the Smarter Long-Term Investment

Choosing between a self bunded tank and a single wall tank is more than just a cost decision, it’s a choice about safety, sustainability and long-term value.

Single wall tanks may seem cheaper upfront, but when you account for installation, compliance, maintenance and risk exposure, self bunded tanks deliver far greater value over time.

At Durotank, we’ve spent years refining our self bunded tank designs to meet the highest standards of durability, efficiency and environmental protection. Whether you need a 10,000-litre tank for farm operations or a 100,000-litre system for industrial fuel storage, our solutions are built to perform in Australia’s toughest conditions.

To discover the best option for your site, contact our team today to discuss your needs.