Buying a CW – Cargo Worthy shipping container does not mean it will automatically have a valid CSC plate
In the field of buying and selling shipping containers it is essential to correctly distinguish between the technical condition of a container (marked Cargo Worthy – CW) and its legislative eligibility for international transport (a valid CSC plate). While Cargo Worthy declares the structural integrity and readiness of the container for safe transport, a valid CSC plate is a necessary prerequisite for legal inclusion in international transport under the Convention for Safe Containers (CSC). Ignorance of this difference can lead to complications – from unexpected costs for additional inspections to the detention of the container at a port.
The purpose of this article is to explain both terms in detail, their interrelationship, and the practical consequences for buyers internationally.
Detailed analysis of the issue
Shipping container: Construction, standardization and significance in logistics
Shipping container (ISO container, intermodal container) is a robust and standardized transport unit that has enabled a revolution in global trade and logistics. Key features:
| Feature | Description |
|---|---|
| Material | High‑quality steel, often “Corten” (Corten steel), resistant to corrosion and weather |
| Standardization | Dimensions, load capacities, construction defined by ISO 668, ISO 6346 and ISO 1496 |
| Dimensions | Most common 20’ (TEU, length ~6.06 m) and 40’ (FEU, length ~12.19 m); high‑cube variants also exist |
| Structural elements | Corner castings, reinforcements, ribs for stacking and lifting |
| Floor | Wooden (usually 28 mm plywood), typical load capacity > 2 000 kg/m² |
| Safety | Designed for stacking up to 9 layers and for extreme conditions |
Function of intermodal transport:
The container is designed to be quickly transferred between ship, train and truck without handling the cargo, increasing efficiency and reducing damage risk.
Interesting fact:
According to the OECD, up to 90 % of world cargo is transported in shipping containers.
Classification “Cargo Worthy” (CW): What it really means
Cargo Worthy is an industry standard indicating that a container is structurally suitable for transport of goods by sea, rail and road. This classification can be issued by an experienced inspector or a seller after a visual and functional inspection.
Cargo Worthy criteria
- Structural integrity: No serious deformations, cracks, bends or damage to the frame, walls, roof and floor. Repairs must follow standards.
- Watertightness and wind‑tightness (WWT): No holes, leaks, water or wind ingress.
- Functional doors: Easy opening/closing, intact sealing, no water leakage.
- Floor: No major cracks, rot, and sufficient load capacity.
- Age: Usually 8–15 years, commonly after being withdrawn from the fleet of major leasing companies.
- Surface corrosion: Acceptable if it does not compromise strength or sealing.
Important:
The CW designation is not an official certification – it is a qualitative assessment that merely states the container may be considered suitable for international transport upon inspection.
Comparison of main container classes
| Class | Structural integrity | Watertightness | Suitable for transport | CSC validity |
|---|---|---|---|---|
| Cargo Worthy (CW) | Yes | Yes | Yes | Not always |
| Wind & Watertight | Not always | Yes | No | Usually no |
| IICL (IICL‑5/6) | Highest | Yes | Yes | Always |
CSC plate: Legal certification and its significance
What is the CSC plate?
CSC (Convention for Safe Containers) is an international convention (IMO, 1972) that unifies safety requirements for the construction, inspection and operation of containers. Every container used for international transport must be equipped with a metal CSC plate (safety approval plate), usually affixed to the left door.
Contents of the CSC plate
| Data on plate | Meaning |
|---|---|
| “CSC SAFETY APPROVAL” | Official safety confirmation according to international standards |
| Country of approval, number | Identification of the state and certification body |
| Manufacture date | Initial CSC validity is 5 years |
| Manufacturer, serial number | Enables traceability of the container |
| Maximum gross weight | Safe loading including cargo (in kg and lbs) |
| Permitted stacking load | Load capacity when stacked (at 1.8 g acceleration) |
| Lateral rigidity test | Minimum force the frame must withstand |
| Date of next inspection | Critical datum that determines CSC validity |
Legal significance:
Without a valid CSC plate it is illegal to load the container onto a ship for international voyages. The presence of a plate, however, does not mean it is still valid.
Difference between “having a CSC plate” and “having a VALID CSC plate”
Every new container has a valid CSC plate for 5 years from manufacture. After that, a regular inspection and certification renewal are required.
Inspection systems and CSC validity
| Program | Description | Frequency | Who performs it | Record on plate |
|---|---|---|---|---|
| PES | Periodic Examination Scheme | Every 30 months | Certified inspector (Bureau Veritas, DNV GL, Lloyd’s, etc.) | Date of next check |
| ACEP | Approved Continuous Examination Program | Ongoing, during operation | Large companies/lessors with own approval | ACEP code on plate |
Important:
The CSC plate is valid only if:
- The next inspection date has not passed (under PES), or the container is under an active ACEP program.
If the date has expired, the plate is invalid, even if it is physically present. The container is then illegal for international transport until a new inspection is completed.
Why Cargo Worthy DOES NOT AUTOMATICALLY MEAN a valid CSC plate
The main reason lies in the container’s life cycle:
- Withdrawal from fleet: After 10–15 years of use, the shipping line removes the container from its fleet and deregisters it from the ACEP program.
- Sale on the secondary market: The seller offers the container as CW because it is structurally sound and functional.
- CSC validity: At this stage the certification is often expired. The seller guarantees only the physical condition (CW), not the legal eligibility (valid CSC).
- If the container must be used for transport: A new inspection must be ordered and paid for.
Practical consequence:
If a buyer confuses CW with a valid CSC, the container may be rejected at the port or require costly, last‑minute inspection.
Analogy with vehicle technical inspection
A CW container = a “technically road‑worthy car”, but without a valid MOT it cannot be driven. Similarly, without a valid CSC a container cannot be loaded onto a ship.
Practical implications and recommendations for buyers
For storage (static use):
- CSC validity is not important.
- Focus on CW or WWT class – guarantees a dry, clean, safe space.
- Lower price compared with containers that have a valid certification.
For transport (SOC):
- A valid CSC plate is mandatory!
- Before purchase, request photo documentation of the plate and verify the date of the next inspection.
- If the plate is expired, factor in time and cost (several thousand CZK, days to weeks) for an inspection by a certified organization (Bureau Veritas, DNV‑GL, Lloyd’s Register, etc.).
- Best practice: buy only from suppliers who guarantee CSC validity or provide “turnkey” inspection services.
Procedure when a new certification is needed:
- Order an inspection (PES) from a certified company.
- After a successful check you receive a new plate with a fresh validity date (30 months).
- Service cost depends on region, inspector availability and container condition.
Tip: If you plan transport several months ahead, ensure the CSC validity covers the entire planned journey (some owners require validity for a few months after unloading at the destination port).
Overview of related terms
| Term | Meaning and use |
|---|---|
| IICL (Institute of International Container Lessors) | Highest standard for used containers. Minimal wear, suitable for long‑term transport. |
| WWT (Wind and Watertight) | Guarantees only watertightness, not structural integrity. Suitable for storage, not for transport. |
| SOC (Shipper Owned Container) | Container owned by the shipper. CSC plate is critically important. |
| COC (Carrier Owned Container) | Container owned by the carrier. The carrier handles CSC; the shipper does not need to worry about its validity. |
| One‑Trip | Nearly new containers that have made only one journey from the factory. They always have a valid CSC. |
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