Flexitank or ISO Tank Containers for Bulk Liquid Transport

Posted by: miamiseo
Category: Flexitanks

Flexitanks and ISO tank containers are both used for bulk liquid transportation. Some customers prefer one solution over the other based on tradition but there is still a lack of complete awareness on the benefits and disadvantages of each solution.

Finding the most economical and reliable means of transporting your bulk liquid might not be apparent at a first glance. Bulk liquid transport is a significant section of the transportation industry and while both tanks serve the same purpose of transporting bulk liquids, some distinct differences exist between them. Here’s an overview of the two.


Developed by the American military in the 60s to transport and store fuel and water, the tanks have transformed the logistics industry. They’re the preferred option for transporting non-hazardous liquids, including food-grade liquid and chemicals.

Manufacturers are developing more superior flexitanks with liners, making them perfectly hygienic for food packaging and pharma-grade bulk liquid. As a result, their application is continuously growing world wide with at an unprecedented adoption rate.

Our bulk liquid transportation tank comprises numerous layers of blended polyethylene with an external layer of woven polypropylene. They transportation nonhazardous liquid converting a normal 20-foot dry container into a 24 ton liquid transporter. This conversion of the container makes the flexitanks very appealing as they can be used to transport liquid one way and dry cargo another way.

Types of Flexitanks

There are different kinds of flexitanks and as the industry evolves more innovations and changes are made to suit specific products. Here are some different flexitanks:

Multilayer flexitanks

This flexitanks are normally comprised of two or more layers of polyethylene. The industry standard is 3 layers although many unaccredited manufacturers are flooding the market with 2 layers bags. Techno Tanks Flexitanks have a standard 4 layer bag. It’s important to note that the polyethylene layers have different blends, manufacturing techniques and thickness. This variations mark the difference between a reliable and a risky flexibag.

Monolayer flexitanks

This tank comprises a single polyethylene layer, which is normally thicker than the multi layer tank. The selection of this type of flexitank is dependent on the length of the journey, the type of product and the method of transportation.

Wine and Alcohol flexitanks

This flexibags have different types of layers such ALUM Foil or EVOH that have specific characteristics to control the humidity, temperature and OTR of the product being carried. Techno Tanks Flexitanks can be developed to meet the exact requirements of your product.

Advantages of Flexitanks


They’re cheaper to use than ISO Tank containers and you’re likely to spend significantly than what you’d require to spend when using conventional bulk liquid solutions.

Protection against contamination

Since flexitanks are designed for single-use, flexitanks reduce the likelihood of contamination as the materials are always brand new and sterilized.

Maintain product quality

Flexitanks can be manufactured to suit specific products and this helps maintain the quality of the product intact.

Makes unloading and loading faster

It doesn’t need the use of a forklift to unload or load a container, making the task faster and requiring less men hours. Being a one step load and discharge system the potential for loss of product during transfer is minimal. At max discharge rates, out of 24,000 liters there is normally a 30 liter residual left on the bags; this is 0.001% of the load .

The Preferred method for the transportation of pharma-grade liquid and food

Since flexitanks provide advanced protection against contamination, they’re the preferred means for transporting food-grade bulk liquids, such as beverages and vegetable oils.

No extra storage is necessary

When using our bulk liquid transportation, there’s no need for extra storage because the flexitank is a storage unit itself. If unused, they come in a box and occupy minimal space and are easily movable by one person.

Greater Availability

Other transportation units for bulk liquid need cleaning and shipping to their destination once you use them. This can result in shortages when you have to transport liquids. When it comes to flexitanks, you can ship them virtually anywhere worldwide within days and load them into any available 20-foot common container which are widely available in any part of the world.

Obviously, flexitanks aren’t a one-size-fits-all substitute. They come with some restrictions, which might make the more conventional drums and tanks a better choice for you.

Disadvantages of Flexitanks

Possible Leakage by human error

Even though the technology and manufacturing process of Flexitanks has come a long way, there is still potential for a leak. If the operator overloads, under-loads or punctures the bag with sharp equipment, the likely hood of some type of spill is possible.

Container Selection

Flexitanks put pressure on the sidewall panels of freight containers, therefore it is necessary to make sure that the container used to fit in a flexitank meets the minimum recommended attributes.  It is also imperative that the container be examined and that all nails are removed from the floor and all cracks be properly covered. Some containers are plain unfit to carry a flexitank and this can cause a potential damage to the bag, if the container is not rejected then your risk of having problems is greater, hence, taking the time to examine and prep the container is quite necessary. Prep time normally does not exceed 30 min.

ISO Tanks

The manufacture of these tanks adheres to the ISO standards, making them suitable for various transportation modes. They’re designed to transport gases and liquids in bulk, both non-hazardous and hazardous. The containers are stainless steel-made with protective layers. Their advantages include:



You can stack them with dry box containers or with one another, providing efficient space allocation on vessels if you constantly hold and ship large volume of units.

Sturdiness and flexibility

These containers permit inter-modal logistic between different transportation modes, including trucks, sea vessels, and rail. They are constructed of high grade steel so they are very resistant to impacts. You can also transport hazardous liquids.

Environmental Friendliness

Reported leaks from these containers are very rare and the likelihood of spillage upon discharge or transportation reduces greatly compared to drums or totes.


Sanitation costs

After usage, it is the shippers responsibility to have it cleaned for reuse.

Reposition costs

After usage, it is the shippers responsibility to have it re positioned for reuse.

Container Management

Each ISO tank is the size of a full 20′ container. Although they stack able, if you plan to do this you do require big and heavy machinery to be able to do so. If you have many ISO Tanks on your facility the amount of space they consume is quite large.


ISO tanks are scarce in many parts of the world. Having availability at a moments notice will not be guaranteed as it can be with a standard dry container.

Both flexitanks and ISO tanks have their benefits and drawbacks to consider. Based on your specific circumstances, you now can judge what would be a better option for your company. If you have any questions, don’t hesitate to contact us. Our team is ready to assist you.

Author: miamiseo