The quick answer
The container identification number identifies the equipment; its size/type code describes its format. Door markings and the CSC plate provide weight and safety information. Before buying, check the container’s physical condition, examination status and actual measurements against what you need it to do.
Know the main components
A steel dry container combines corner structures and rails with corrugated wall and roof panels. Cross-members support the floor, while the cargo doors use hinges, locking gear and seals. Floor materials and construction details vary, so look at the container you’re considering.
| Component | What to discuss |
|---|---|
| Corner posts, corner fittings and rails | Condition, deformation, corrosion and previous structural repairs. |
| Roof and wall panels | Holes, patching, dents and signs of water entry. |
| Floor and supporting structure | Surface damage, soft areas, repairs and suitability for the intended load. |
| Door leaves, locking bars and hinges | Operation, alignment and the ability to close and secure the unit. |
| Door gaskets and seals | Condition and the seller’s stated weather-resistance criteria. |
| Vents or installed equipment | What is present, whether it operates, and the scope of any promised performance. |
Use this list to prepare questions for the seller. It does not replace a structural inspection or repair standard.
Read the container identification number
The international identification system uses three owner/operator letters, an equipment-category letter, six serial digits and a check digit. The letter U identifies freight containers. The check digit helps detect errors when the identification number is copied or transmitted.
Take a photo of the complete number and match it to the container photos, condition report and delivery paperwork. This helps you keep the records for the same container together. The number alone doesn’t prove its condition, the seller’s ownership or suitability for what you plan to store.
Read the size and type code
Look for the four-character size/type code to identify the container’s format. For the common examples in this reference, 22G1 identifies a 20ft standard dry container, 42G1 a 40ft standard dry container, and 45G1 a 40ft high-cube dry container.
Use the code to check that the height and category in your quote match the photos. You’ll still need clear-opening measurements and details of any extra doors, installed equipment or later alterations; the code doesn’t describe every feature.
Use the weight markings and CSC plate together
Look for the maximum gross weight and tare markings, and any stated net or payload value. Maximum gross includes the container and its load. The CSC plate also records safety data. If its gross rating differs from the rear-door marking, the CTU Code directs you to use the CSC plate value.
Ask for readable photos of the markings before making a purchase or transport plan. If a figure is unclear, have it explained. Discuss heavy loads with the relevant equipment and transport professionals so you’re working from the container’s actual ratings and the requirements of the move.
Understand examination status
Under the periodic examination scheme, the first examination is due within five years of manufacture, with later intervals no longer than 30 months. An approved continuous examination program is another route; ACEP identification indicates that scheme. Whichever scheme applies, the container’s physical condition still matters.
If you’ll be shipping the container, ask the seller or carrier which current documents you need for that journey. For storage, agree on its condition in writing even if international transport isn’t planned. A visible plate alone can’t answer every question about the container.
Check assumptions again after modifications
Before cutting openings or making major repairs, ask how the work affects the container. IICL notes that major repairs and modifications follow different requirements. Keep a record of the work, its design basis and how you’ll use the space; the original ratings don’t automatically cover the finished result.
For plain storage, have the quote identify the container, its condition and what delivery includes. If you want modifications, ask for that work to be described separately so you can review it before work begins.
Related questions
Does a CSC plate guarantee the container is currently cargo worthy?
Check the plate alongside the container’s current condition and examination status. If you’ll be transporting it, ask for up-to-date evidence for that journey; the plate’s presence alone is not enough.
Can a size/type code tell me the exact door clearance?
It tells you the broad format and characteristics. For a close fit, use the relevant specification and measure the actual opening.
What photos should I ask for?
Ask for the container number, a readable plate and weight markings, inside and outside views, flooring, doors, and any damage or repairs that matter to the condition you’ve agreed to buy.
Sources & reference notes
These specifications are examples unless they identify a particular container. Follow the sources for more detail, and check your container’s measurements and ratings before making a decision.