Operational Guide · Registers & Logbooks

# CTU Code: Packing and Stowage of Cargo Transport Units

The IMO/ILO/UNECE Code of Practice for the packing of Cargo Transport Units provides practical guidance for filling, stowing and securing cargo inside containers and other transport units, with particular attention to dangerous goods.

CTU Code container packing dangerous goods

## Operational Explanation

The CTU Code (Code of Practice for Packing of Cargo Transport Units) was developed jointly by IMO, ILO and UNECE to provide practical guidance to anyone filling or stowing cargo in a Cargo Transport Unit (container, tank, vehicle), including procedures for dangerous goods. Unlike the IMDG Code, which governs classification and labelling, the CTU Code focuses on the operational practice of packing and securing cargo inside the transport unit.

The supporting informative material (MSC.1/Circ.1498) provides further practical and background guidance on applying the Code.

## Regulatory Reference

The CTU Code (2014, developed by IMO/ILO/UNECE) is not mandatory in itself but is referenced as a good-practice reference by the IMDG Code for the packing of transport units; MSC.1/Circ.1498 provides complementary informative material.

## Scope of Application

Anyone involved in filling, stowing and securing cargo inside containers or other CTUs, including terminal personnel, shippers and the crew members who receive and check the units before loading.

## Procedure / How to Complete It

1. Check the structural suitability of the CTU (integrity, weathertightness, absence of damage) before filling it.
2. Apply the segregation and compatibility rules between different goods inside the same unit, in accordance with the IMDG Code.
3. Stow liquid dangerous goods below solid ones where possible, and secure the cargo against movement during transport.
4. Check that the external labelling of the CTU (placarding) is consistent with the declared contents.
5. Check the weight distribution inside the CTU to avoid instability or localised overloading.

## Practical Example

Example: a container with packages of dangerous goods of different but compatible classes is filled according to the IMDG segregation tables, with liquids positioned below solids and the cargo secured with nets and straps to prevent movement at sea.

## Real Cases

Numerous analyses of incidents on board container ships (including fire episodes linked to dangerous goods) have identified poor packing and securing inside the CTU, rather than misclassification alone, as a contributing factor: a correctly classified package that is poorly secured inside the container can still shift, be damaged and generate a leak or an ignition source during the voyage.

## Common Mistakes Mistake Library

Mistake | Consequence | How to avoid it
--- | --- | ---
CTU filled without a prior check of the structural integrity of the unit | Risk of loss of tightness or structural failure during transport | Always inspect the CTU before filling it, even when supplied by a third party
Liquid dangerous goods stowed above solid goods in the same unit | Risk of contamination or damage in the event of a leak | Always apply the liquids-below-solids stowage rule set out in the CTU Code
External placarding of the CTU not updated after changes to the contents | Misleading information for terminal personnel and emergency responders | Check the consistency between external placarding and actual contents before final closure

## PSC Observations

PSCOs may check on a sample basis the integrity of CTUs containing dangerous goods, the consistency of external placarding with the transport documentation, and any visible signs of damage or cargo instability.

## Operational Tips

- Do not rely solely on the shipper's documentation: a visual inspection of the CTU before loading remains the most effective defence against non-compliant packing.
- Consult the MSC.1/Circ.1498 informative material for practical examples of applying the CTU Code, useful for crew training.
- Pay particular attention to weight distribution: an unbalanced CTU is a risk even if the contents are correctly classified.

## Checklist

- Structural integrity of the CTU checked before filling
- Segregation and compatibility rules applied inside the unit
- Liquids stowed below solids where possible
- External placarding consistent with the declared contents
- Weight distribution checked to avoid instability

## FAQ

Is the CTU Code mandatory?
It is not a mandatory code in itself, but it is a good-practice reference widely cited by the IMDG Code and adopted as an operational standard by the industry for packing transport units.
How does it differ from the IMDG Code?
The IMDG Code governs classification, packing of individual packages, labelling and documentation; the CTU Code focuses on the practice of filling and securing cargo inside the transport unit as a whole.
Who is responsible for applying the CTU Code?
Primarily whoever physically fills the CTU (terminal or shipper), but the ship still has an interest in checking its application before accepting the unit on board.
🎬 Additional photos, videos and interactive diagrams for this topic will be available in a future version of the platform.

## Related Topics

Dangerous Goods Manifest and Notification to Port Authorities Cargo Securing Manual and Cargo Lashing

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