Shipping Container Grades Explained: New, Cargo-Worthy, Wind & Watertight and As-Is

Two sellers can advertise a “cargo-worthy 20ft” and deliver visibly different containers. Neither is necessarily lying. Container grading in Australia is a set of trade conventions rather than a regulated classification system, and only one term in common use — cargo-worthy — is anchored to anything formal at all.

This guide defines each grade, sets out what you should actually expect to see, explains what CSC plating does and does not certify, and gives you a checklist for inspecting a container before you pay for it.

Grading is a trade convention, not a standard

This is the single most useful thing to understand before you shop. There is an international convention governing container safety (the CSC, covered below) and an ISO standard governing container dimensions. There is no equivalent standard governing the words sellers use to describe cosmetic condition.

The practical consequences:

• “A-grade”, “B-grade”, “premium”, “refurbished” and “good used” mean whatever the seller has decided they mean. Ask what defects the unit has.
• “Wind and watertight” describes a test outcome, not a certification. Anyone can apply it.
• “Cargo-worthy” is the one grade tied to an inspectable outcome — a surveyor certifying the unit fit to be loaded and shipped. Ask whether a survey exists and when it was done.
• Photographs of the actual unit are worth more than any grade label.

None of this is a reason for suspicion. It is a reason to ask specific questions.

The grades, one by one

New / one-trip

“New” is slightly misleading. Almost every container sold as new in Australia is a one-trip unit: built in Asia, loaded with cargo for a single voyage to Australia, then sold here. Genuinely unused containers exist but are rare and cost more.

What to expect: factory paint in good order, clean marine ply floor, seals intact, doors operating smoothly, current CSC plate. Minor scuffs, a few surface marks from lashing gear and small transit dents are normal — a one-trip container has genuinely been to sea.

Fit for: anything. Long-term storage where appearance matters, conversions, container homes and offices, export, and any application where you want the longest possible service life before maintenance starts. Price position: the top of the market for a given size.

IICL

IICL refers to the inspection criteria published by the International Institute of Container Lessors, used across the leasing industry to decide what damage is acceptable and how repairs must be done. An IICL-graded container has been assessed against those criteria and is structurally sound with repairs completed to a consistent standard.

You will see this term far more often in leasing and international trade than in Australian retail. If a seller offers it, it sits between one-trip and ordinary cargo-worthy: used, but held to a documented inspection regime rather than an opinion.

Cargo-worthy

The workhorse used grade, and the only one with a functional definition. A cargo-worthy container has been surveyed and found structurally sound enough to be loaded with cargo and stacked on a ship. It is wind and watertight by definition, has no holes or through-rust, has sound doors and floor, and holds valid CSC certification.

What to expect: honest wear. Surface rust, patched repairs, dents, faded and mismatched paint, scuffs, a floor with forklift marks. It will look used, because it is. What it will not have is anything compromising its structure or its seal.

Fit for: everything except applications where appearance is the point. This is the grade to buy if the container will be shipped — see our export-ready stock — and it is usually the best value for serious storage. Price position: typically well below one-trip; our Australian price guide sets out the current spread.

Wind and watertight (WWT)

A container that keeps weather out. The practical test is simple and worth doing yourself: close the doors, stand inside, and look for daylight. Any pinhole you can see is a leak you will find later.

The important distinction is that wind and watertight says nothing about structure. Many WWT units are older boxes that can no longer be safely stacked when loaded and therefore would not pass a cargo-worthy survey — they are sound and dry, but retired from sea service. That is exactly why they are cheaper, and exactly why they are fine for the job most Australian buyers actually have.

Fit for: on-site storage, farm and workshop use, site sheds, anything static. Not fit for: export, or anything requiring the container to be stacked loaded. Browse used containers if this is the grade that suits you.

As-is

Sold in its current condition, with known faults, at a discount, with no undertaking that it is watertight. An as-is container may have a hole in the roof, a rusted-through corner, a sagging floor, a door that will not seal, or a wall panel pushed in.

These are legitimate purchases for the right buyer: someone cutting the unit up for materials, using it as a blast wall or bund, building something where the steel is a component rather than an enclosure, or willing to do the repairs. They are a poor purchase for anyone who needs dry storage, because the repair cost frequently exceeds the saving.

Buy as-is only if you have seen photographs of the specific defects, or better, seen the unit.

Grades at a glance

Grade	What you should see	Best suited to	Can be exported?	Price position
New / one-trip	Factory paint, clean floor, minor transit marks	Conversions, homes and offices, presentation-critical storage, export	Yes	Highest
IICL	Used but inspected to published leasing criteria; repairs done to standard	Shipping, leasing, buyers wanting documented condition	Yes	High
Cargo-worthy	Surface rust, dents, patch repairs, valid CSC plate, no holes	Export, and the best value for serious storage	Yes	Mid
Wind & watertight	Dry and sealed, but may not be stackable when loaded	Static on-site storage, farm and workshop use	No	Lower
As-is	Known, disclosed faults; watertightness not guaranteed	Materials, structures, buyers doing their own repairs	No	Lowest

CSC plating: what certification actually means

The International Convention for Safe Containers was adopted on 2 December 1972 and entered into force on 6 September 1977. It has two stated aims: to maintain a high level of safety of human life in the transport and handling of containers, and to facilitate international container transport through uniform international safety regulations rather than a patchwork of national ones.

Approved containers carry a safety approval plate — the CSC plate — usually bolted to the left-hand door. It records the container’s identification and date of manufacture, its maximum gross mass, its allowable stacking load and racking test load, and the examination regime it sits under.

ACEP and PES

Once a container is approved, keeping it safe is the owner’s responsibility, and the convention requires periodic examination. There are two routes:

• PES, the periodic examination scheme: the first examination within five years of manufacture, then examinations every 30 months.
• ACEP, an approved continuous examination programme: the container is examined as part of the owner’s ongoing maintenance regime, including whenever structural repairs are carried out. ACEP programmes must be reviewed at least every ten years.

The plate tells you which applies. On a PES container, look for the next examination date — if it has passed, the certification has lapsed.

When the plate matters and when it does not

If the container will be used in international transport, valid CSC certification is not optional. If the container is going to sit on your property holding tools for the next fifteen years, it is irrelevant to you — the plate certifies fitness to be stacked and shipped, not fitness to keep the rain off a ride-on mower.

This is worth knowing because an expired plate is a legitimate reason for a container to be cheaper without being any worse for storage. Do not pay a premium for certification you will never use, and do not accept a lapsed plate on a container you intend to ship.

Common defects and what they actually mean

Rust

Containers are built from weathering steel, which develops a stable surface oxide. Surface rust on a used container is normal and cosmetic. What matters is through-rust: perforation, or scale you can push a screwdriver through. Check the underside of the floor structure and the bottom side rails, which sit closest to standing water and are where terminal corrosion usually starts. Rust in a corner casting or corner post is serious, because that is where all the structural load goes.

Dents and distortion

Dents in corrugated wall panels are almost always cosmetic. Distortion of the frame is not. Sight down each long wall: a container that has been racked or dropped will show a wave in the panel line, and the doors will be the first thing to tell you — if they need forcing, the frame is out of square. A twisted container placed on uneven ground will do the same thing, so check it standing level.

Floors

Most containers have a marine-grade plywood deck laid on steel cross-members. Look for soft spots, delaminating plies, gouges from forklift tynes, and patch repairs. Walk the whole length and feel for flex. A container that has carried something that soaked into the ply will smell — trust your nose. Steel-floored units exist and take much heavier point loads, but are less common in retail stock.

Doors, seals and locking gear

The most common source of complaint after purchase. Open and close both doors fully. The cam handles should engage without fighting. Check the rubber gaskets along their whole length for splits, hardening, flattening or sections that have pulled away. Check the hinges for seized pins and the lock rods for bending. Doors that have been forced on a distorted frame will never seal properly.

Roof

The most neglected panel and the one where leaks originate. Roofs get dented by handling gear, and a dent that holds water will rust through. If you can safely see the roof, look for ponding damage and repairs. If you cannot, the daylight test from inside will find the holes for you.

Pre-purchase inspection checklist

• Stand inside with the doors closed and let your eyes adjust. Any daylight is a leak. Check the roof, the door seals and the corner joints.
• Check the floor end to end for soft spots, delamination and smell.
• Work both doors through their full swing. Check gaskets, hinges, cam handles and lock rods.
• Read the CSC plate: manufacture date, maximum gross mass, ACEP or next examination date.
• Inspect the bottom rails and underside for through-rust. Bring a torch.
• Sight down each side wall for frame distortion.
• Check the corner castings and posts for cracks, heavy corrosion or weld repairs.
• Look at the paint: fresh paint over a whole used container may be cosmetic refurbishment or may be hiding repairs. Ask which.
• Ask for the survey if it is sold as cargo-worthy, and note its date.
• Get the defects in writing before you pay, especially on as-is stock.

Buying without seeing it first

Most Australian container purchases happen sight-unseen, because the container is at a depot hundreds of kilometres from the buyer. That is normal and workable, but it changes what you should ask for: photographs of the actual unit including the interior, the roof if possible and the CSC plate; the specific defects in writing; and clarity on whether you are buying a nominated container or simply “a container of that grade” from a pool.

Once you have settled on a grade, the remaining decisions are size and siting. Our full metric dimensions guide covers the first, and the state-by-state guide to council approval covers the second. If you are still weighing the grade decision itself, our comparison of new versus used containers works through it from the buyer’s side.

About this guide

Australian Containers is a Queensland-based supplier of new and used containers, delivering Australia-wide for a flat $450 regardless of distance. We have written this guide to make grading legible rather than to make any particular grade sound better — the right grade is the cheapest one that does your job. If you tell us what the container is for, we will tell you which grade you actually need.

Sources

• International Maritime Organization — International Convention for Safe Containers (CSC), 1972. Source of the adoption and entry-into-force dates, the convention’s two stated aims, the safety approval plate requirement and the owner’s periodic examination obligation.
• Shipping and Freight Resource — All about the CSC plate and inspection regimes for shipping containers. Source of the plate contents, the ACEP ten-year review requirement and the PES intervals (first examination within five years of manufacture, then every 30 months).
• Four Sons Logistics — Shipping Container Grades: As-Is, Cargo-Worthy & IICL Guide. Source of the working definitions of one-trip, IICL, cargo-worthy, wind and watertight and as-is grades and what each is fit for.
• Boxhub — A Guide to CSC Shipping Container Certification, on CSC plate contents and the requirement for third-party certification before international use.
• Hapag-Lloyd — Container Specification (PDF), for container construction detail including floor and axle load specifications.

Last reviewed July 2026. Grade terminology is a trade convention and is not regulated in Australia; always confirm the specific condition of the specific container you are buying.