What Is a Flexitank? A Complete Guide for Bulk Liquid Shippers

A flexitank is a single-use, collapsible bladder made from multiple layers of polyethylene (PE) and polypropylene (PP) film, installed inside a standard 20-foot ISO dry container to transport non-hazardous bulk liquids. With a typical capacity of 16,000 to 24,000 litres, a flexitank converts an ordinary dry box into a cost-effective bulk liquid carrier — without the capital expense or operational complexity of a dedicated ISO tank container. Flexitanks are widely used across the food-grade, chemical, and agricultural industries for commodities such as edible oils, fruit juices, industrial lubricants, and non-hazardous liquid chemicals.

How Does a Flexitank Work?

A flexitank system consists of three main components: the bladder itself, a filling and discharge valve, and the host 20-foot dry container. Before loading, a trained technician installs the deflated flexitank bladder inside the container — a process that typically takes 20 to 45 minutes. The bladder is positioned against the container doors and secured to prevent movement during transit.

Cargo is pumped directly into the bladder through a 3-inch or 4-inch butterfly valve mounted at the container door. Once filled, the valve is sealed and the container doors are closed. At destination, the liquid is discharged by gravity or pump through the same valve. After discharge, the flexitank is removed and disposed of — it is a single-use product.

The multi-layer construction is critical. The innermost layer is food-grade low-density polyethylene (LDPE), which provides chemical inertness and prevents contamination of the cargo. Outer layers of woven polypropylene provide structural integrity and resistance to abrasion and puncture during transit.

Flexitank Technical Specifications

Standard flexitank specifications are largely consistent across manufacturers, though slight variations exist depending on the supplier and cargo requirements:

Specification	Standard Value / Range
Capacity	16,000 – 24,000 litres (most common: 18,000 – 21,000 L)
Compatible container	20-foot ISO dry container (standard or high-cube)
Number of layers	3 – 5 layers (PE inner + woven PP outer construction)
Inner layer material	Food-grade Low-Density Polyethylene (LDPE)
Outer layer material	Woven Polypropylene (PP) with UV-resistant coating
Discharge valve	3-inch or 4-inch butterfly valve (rear door mounted)
Max payload weight	~21,000 – 24,000 kg (subject to container floor load limit)
Filling time	Approximately 1 – 3 hours depending on pump capacity
Discharge time	Approximately 2 – 4 hours (gravity or pump-assisted)
Operating temperature	-5°C to +40°C (ambient); heated variants available for viscous cargo
Installation time	20 – 45 minutes by a trained technician
Common certifications	ISO 9001, FSSC 22000 (food-grade), UN/ADR (select non-hazmat grades)

 

What Commodities Can Be Shipped in a Flexitank?

Flexitanks are approved for non-hazardous liquid cargo only. This covers a broad range of food-grade and industrial products, but explicitly excludes dangerous goods regulated under IMDG, ADR, or RID (see limitations below). Common commodity categories are:

Commodity Category	Typical Products	Notes
Edible oils	Sunflower, palm, soybean, rapeseed, coconut oil	Most common flexitank cargo globally
Food-grade liquids	Fruit juices, wine, liquid glucose, starch syrup, honey	Food-grade PE inner layer required
Industrial chemicals (non-hazmat)	Glycerin, latex, liquid fertiliser, lubricant base oils	Must be non-classified under IMDG/ADR
Agricultural liquids	Liquid molasses, animal feed liquids	Standard flexitank grades
Cosmetic & pharma ingredients	Liquid wax, vegetable glycol, non-hazardous excipients	Confirm food/pharma-grade bladder spec
NOT suitable	Hazardous chemicals (Class 3/6/8), pressurised cargo, high-viscosity solids	ISO tank container required for these

 

Advantages of Flexitank Shipping

Flexitanks offer several distinct commercial and operational advantages over alternative bulk liquid transport methods — particularly for non-hazardous cargoes on longer trade lanes:

• Cost savings of 20–35% vs ISO tank containers: No equipment repositioning cost, no cleaning cost, and no demurrage on specialised equipment. The dry container used is part of the standard global pool.
• No return logistics: Because the flexitank is single-use, the empty dry container can be repositioned normally after discharge. There is no obligation to return a specialised tank to its owner.
• Global container availability: Standard 20ft dry containers are available at virtually every port and inland depot worldwide, removing equipment supply constraints that affect ISO tank operations.
• Rapid installation: A trained operator can install a flexitank in 20–45 minutes. No special terminal infrastructure is required — filling can be done at the shipper’s premises.
• Food-grade hygiene guarantee: Each flexitank is new and unused, eliminating cross-contamination risk. This is particularly valued by edible oil and food ingredient shippers.
• Lower minimum order threshold: Shippers can move as little as 16,000 litres per shipment — significantly less than the minimum economic load for a tanker vessel or rail tank car.

 

Limitations of Flexitanks: When NOT to Use One

Flexitanks are not a universal solution. Several cargo types and operational scenarios require an ISO tank container or another form of bulk liquid packaging:

• Hazardous materials: Flexitanks are not UN-certified for dangerous goods. IMDG Class 3 (flammable liquids), Class 6 (toxic), Class 8 (corrosive), and most Class 9 cargoes require an ISO tank container with the appropriate T-code rating.
• High-viscosity cargo above 40°C heating requirement: Standard flexitanks operate at ambient temperature. Certain palm oil, bitumen, or chemical products requiring sustained heating above 40°C are better suited to a heated ISO tank.
• Repeated shipments of the same cargo between fixed points: If the same shipper moves the same product on the same trade lane continuously, an ISO tank on a round-trip cycle can become more cost-effective over time due to amortised equipment costs.
• Cargo requiring multiple discharges: Flexitanks must be fully emptied in a single discharge event. Partial discharge is not practical. If the consignee needs multiple deliveries from one tank, an ISO tank with a bottom outlet valve is the better option.
• Environmental sensitivity: Flexitanks are single-use plastic products. Some shippers with sustainability commitments prefer reusable ISO tanks to minimise plastic waste, though some flexitank manufacturers offer recycling programmes.

 

Flexitank vs ISO Tank Container: A Quick Comparison

Choosing between a flexitank and an ISO tank container depends primarily on cargo classification, trade lane economics, and required delivery flexibility:

Factor	Flexitank	ISO Tank Container
Suitable for hazmat	No	Yes (with correct T-code)
Capacity	16,000 – 24,000 L	21,000 – 26,000 L
Cost per trip (non-hazmat)	Lower	Higher (equipment + cleaning)
Reusability	Single-use	Reusable (15–25 year lifespan)
Return logistics	None required	Required (repositioning cost)
Installation infrastructure	Standard dry container + pump	Dedicated tank depot required
Food-grade suitability	Yes (with food-grade grade)	Yes (with food-grade certification)
Heating capability	Limited / special order	Standard option
Regulatory compliance	Non-hazmat only	ADR, IMDG, RID certified

 

Key Trade Lanes for Flexitank Logistics

Flexitanks are used on virtually all major containerised trade lanes. The following corridors are particularly active due to the volume of non-hazardous bulk liquid trade they carry:

Europe ↔ CIS and Central Asia

This corridor carries significant volumes of edible oils, glycerin, and food-grade liquids between Eastern Europe, Russia, Kazakhstan, and Uzbekistan. Flexitanks are the dominant mode for non-hazmat bulk liquids here due to the wide availability of standard dry containers and limited ISO tank depot infrastructure in inland Central Asian destinations.

Asia ↔ Europe

Southeast Asia (Malaysia, Indonesia) and India ship large volumes of palm oil and other vegetable oils to European refineries and food manufacturers. Flexitanks are the standard vessel for this trade. China also ships industrial liquids westward via sea and increasingly via rail (Trans-Caspian route).

Europe ↔ Middle East and Turkey

Food ingredients, edible oils, and non-hazardous industrial liquids move regularly between European producers and Middle Eastern/Turkish buyers. Flexitanks work well on both deep-sea and short-sea segments of this trade lane.

Frequently Asked Questions About Flexitanks

How much does a flexitank cost?

A standard flexitank bladder (supply only) typically costs USD 200–500 depending on capacity, number of layers, and food-grade specification. All-in logistics costs — bladder, filling, shipping, and discharge — vary by origin and destination. Contact your freight forwarder for a full landed cost comparison.

Can a flexitank be reused?

No. Flexitanks are designed for single use only. Once discharged, the bladder must be removed and disposed of. Reusing a flexitank is not recommended and may void insurance and food-safety certifications.

What is the maximum weight a flexitank can hold?

The maximum fill weight is constrained by the container floor load limit — typically around 21,600 kg for a standard 20ft container. For denser liquids (e.g., glycerin at 1.26 kg/L), this limits usable capacity. Always verify floor loading for your specific commodity and container combination.

Are flexitanks approved for organic or kosher certified cargoes?

Yes. Many flexitank suppliers hold FSSC 22000, BRC, or Kosher/Halal certifications for their food-grade bladder lines. Certification documentation should be requested from the flexitank manufacturer and kept on file for each shipment.

What happens if a flexitank leaks?

Reputable flexitank suppliers carry cargo liability insurance. In the event of a leak, the shipper should document the damage immediately, retain all packaging materials, and file a claim through the flexitank supplier’s insurance programme. The single-use construction means liner failure, while uncommon, is the most significant risk — mitigated by selecting suppliers with multi-layer construction and proven track records.

 

Ship Your Bulk Liquids with Kricongroup

Kricongroup specialises in flexitank and ISO tank container logistics for non-hazardous and hazardous bulk liquids across the Europe–CIS, Asia–Europe, and Europe–Middle East corridors. Our team handles end-to-end coordination — from flexitank supply and loading supervision to customs clearance and final-mile delivery.

Whether you are moving edible oils from Southeast Asia, industrial chemicals across the CIS, or food ingredients between Europe and the Middle East, we can help you identify the right solution for your cargo and trade lane.

Contact us for a tailored flexitank quotation: www.kricongroup.com  |  info@kricon.net