Container Owner/Operator Introduction

Understanding Your Responsibilities for Standard Freight and Modified Containers

Due to the lack of accessible resources for small-scale and shipper-owned containers, this introduction supports both standard and modified container owners. It provides essential information to help owners understand their responsibilities under applicable standards, conventions, and best practices related to container safety, maintenance, and compliance.

Containers Construction and Certification

Containers intended for international intermodal transport—by sea, rail, or road—must meet the construction and testing requirements established by the International Convention for Safe Containers (CSC), 1972, as amended. These requirements are verified by national authorities through recognized classification societies or competent companies.

The International Organization for Standardization (ISO) specifies construction and testing criteria in ISO 1496-1 for general-purpose freight containers. ISO 668 defines standard container lengths (10 ft, 20 ft, 30 ft, 40 ft, and 45 ft), all of which share a uniform width of 8 ft.

Containers constructed and tested in accordance with ISO 1496-1, approved under the procedures of the International Convention for Safe Containers (CSC), and marked in accordance with ISO 6346 are eligible for a CSC Safety Approval Plate, which certifies compliance with structural safety requirements and includes load limits and other essential data.

Note: Approximately 1 in 50 newly manufactured containers (approved by design type series) undergoes a full racking force load test.

Modification of Containers

A modified container is any container that has undergone structural changes—such as the addition of doors, frames, or cutouts—or has been otherwise altered or customized for specialized use. These modifications often include integrated features to meet specific operational needs while remaining compatible with the intermodal container handling and transportation chain.

Due to structural changes, modified containers must be re-evaluated in accordance with CSC Regulation 11. The container must then be re-approved by a competent authority to retain its CSC plate and remain compliant for international use. Retesting may also be required prior to recertification, as determined by the competent authority.

Note: Modified containers should not be confused with ‘temporary modifications’ such as “One Door Off/Open”-operation, as described in CSC Edition 2014, Section 8.1.

Operating and Owning a Container

Owning or operating a container—whether standard or modified—comes with specific responsibilities that go beyond initial certification. Owners must ensure ongoing compliance with international and national standards. This section outlines key obligations every container owner or operator should be aware of.

Owner’s Responsibility for CSC Plate and Markings

Container owners are responsible for ensuring that the CSC Safety Approval Plate is:

• Permanently affixed in a visible location,
• Legible at all times,
• Reflecting accurate and up-to-date information.

In addition, all containers must be maintained and marked in accordance with ISO 6346, which includes:

• The correct container identification number,
• Proper placement and size of mandatory markings,
• Use of a valid owner code (prefix).

Note: If the owner code (e.g., ABCU) is not owned by the operator, there should be a documented agreement authorizing its use. Although registering the owner code with the Bureau International des Containers (BIC) is not mandatory, it is highly recommended to prevent duplication or disputes.
Additional Note: For modified containers achieving compliance under the Modified Container Code (MCC) and registered through the ModConReg platform, a dedicated MITU-prefixed identification number is assigned. This code is legally tied to the unit and listed publicly via ModConReg, allowing for verified lookups of the actual owner through the container number (e.g., MITU 123456-1).

Insurance and Liability Implications

Failure to comply with CSC requirements or ISO standards may result in:

• Insurance claims being denied, especially in case of damage or injury,
• Increased liability exposure for the owner or operator,
• Potential port or carrier refusal to load non-compliant containers.

Inland Use vs. International Use

Containers used solely for domestic or inland applications may not be subject to CSC. However:

• They must still comply with national safety and transport regulations, and
• If later intended for international intermodal transport, the container must be inspected and re-certified in compliance with CSC requirements prior to export.

Note: Always maintain clear documentation of use classification to avoid complications at borders or terminals.

Container Maintenance and Inspection Responsibilities

For All Containers:

Under the CSC, containers must be inspected either:

• At regular intervals (every 30 months) under the Periodic Examination Scheme (PES), or
• Through an Approved Continuous Examination Programme (ACEP).

Both systems aim to ensure continued structural safety and compliance. ACEP is commonly used by large fleet operators, while PES remains accessible and practical for individual or modified units. Inspections under either scheme must be carried out by a competent person or authorized company in accordance with CSC requirements.

The IMO’s CSC.1/Circ.138 outlines that each examination should include a detailed visual inspection of all structurally significant components—particularly corner fittings—to identify any damage, deterioration, or safety-related deficiencies.

For Modified Containers:

Based on extensive experience in managing modified containers, the Modified Container Code—issued by the International Institute of Modified Containers (IIMC)—requires the use of the
Periodic Examination Scheme (PES) over ACEP. PES provides a more suitable framework for modified containers due to the following:

• Modifications may alter structural behavior, requiring specific risk assessments and tailored maintenance routines.
• ACEP may lack the specificity needed to account for unique modifications.
• PES ensures each unit undergoes inspection prior to being placed back into service, enabling informed decisions between inspectors and owners.

Maintenance Records and Traceability (PES)

If a container is maintained under the Periodic Examination Scheme (PES):

• The owner must retain inspection records and supporting documentation,
• Records should demonstrate compliance and traceability,
• Logs may be maintained digitally or physically, but must be available for audit or verification.

Note: The ModConReg platform integrates PES into its workflow to ensure compliance and safety verification for certified modified containers.

If a container no longer complies with applicable requirements or is deemed unsuitable for use in intermodal transport, its CSC Safety Approval Plate must be neutralized.

Container Packing/Stowage (Modified Containers with permanently installed equipment)

All permanently installed equipment must be securely and permanently affixed to the container or its structural components. Any anticipated cargo must meet, at a minimum, international standards for packing and securing.

The CTU Code (Code of Practice for Packing of Cargo Transport Units) provides international guidelines for safe and secure loading practices. It highlights the risks posed by improper packing, misdeclared cargo, and overloading.

CTU Code warning:
Improperly packed and secured cargo, the use of unsuitable CTUs, and the overloading of CTUs may endanger persons during handling and transport operations.

Modified containers not intended for temporary admission under the Customs Convention on Containers (CCC) may omit certain customs-specific provisions, but should still adhere to the principles outlined in Annex 4 of the Convention.

For project developers and owners of modified containers:

A directory of competent workshops and authorized assessors—qualified to modify and approve modified containers—is available at modconreg.com. This directory serves as the official membership listing of the International Institute of Modified Containers (IIMC) and is maintained to ensure that container owners and operators have access to professionals who meet the requirements of the Modified Container Code (MCC) and all applicable standards, regulations, and international conventions.

This guidance will be updated as necessary. Owners and operators are encouraged to submit comments or questions to help evolve this document into a practical FAQ and resource hub for container ownership and operations.