Technical Resource

CSC Certificate vs Seaworthy Certificate: What Each One Proves

Buyers and shippers often ask for a container "with a CSC certificate" or "with a seaworthy certificate" as if the two were the same document. They are not. The CSC approval is a regulatory regime: it says the container type is approved as a safe structure for international transport and that its examinations are up to date. A seaworthy, or cargo worthy, certificate is a commercial survey: it describes the condition of one specific container on one specific day. A container can hold one without the other. This guide explains what each document is, who issues it, what it does and does not cover, how long it remains valid, and which one your operation actually needs.

The short answer

Two documents, two different questions

The CSC answers a safety question: may this container be handled, stacked and transported internationally without endangering people? It is governed by the International Convention for Safe Containers, adopted in 1972 under the International Maritime Organization (IMO) and in force since 1977, and it is carried on the container itself, on the Safety Approval Plate.

A seaworthy or cargo worthy certificate answers a commercial question: is this particular box, today, in a condition that will protect cargo on a sea voyage and be accepted by a carrier? It is a survey report issued after a physical inspection against stated criteria. No convention defines it, and its value depends entirely on who inspected the container, against which criteria, and when.

In practice, an export or one-way shipment needs both: a valid CSC status, because terminals and carriers will not load a container without it, and a cargo worthy condition, because the cargo has to arrive dry and the box has to survive the voyage.

The regulatory regime

What the CSC actually is

The Convention requires every container used in international transport to be approved as a safe design. The approval is granted by a national Administration, or by an organisation it authorises, usually a classification society, after prototype testing to the Convention's loads: stacking, racking, lifting, floor strength and end and side wall strength. Containers built to an approved design then receive a Safety Approval Plate.

The plate is a permanent, non-corrosive, fireproof plate of at least 200 x 100 mm, fixed near the doors. It carries the words "CSC SAFETY APPROVAL", the country and reference of the approval, the date of manufacture, the manufacturer's identification number, the maximum operating gross mass, the allowable stacking load and the transverse racking test load, plus either a next examination date or the reference of a continuous examination programme.

When the trade speaks of a "CSC certificate", it usually means one of three things: the approval certificate issued for the design, the plate itself, or the report of a periodic re-examination that renews the next examination date on the plate. For a buyer, the plate and the latest examination are what matter. Our guide to the CSC plate explains how to read each field.

Staying valid

Periodic examination (PES) and ACEP

A CSC approval is not valid for life. The owner of the container is responsible for keeping it in a safe condition, and the Convention offers two ways to prove it.

Under the Periodic Examination Scheme (PES), the first examination must take place no later than five years after the date of manufacture, and each following examination no later than 30 months after the previous one. The next examination date (NED) is marked on or next to the plate. Once that date has passed, the container must not be used in international transport until it has been re-examined.

Under an Approved Continuous Examination Programme (ACEP), the owner examines the container at regular operational events, typically gate-in and gate-out at depots and repair interchanges, under a programme approved by a national Administration. The container then shows the ACEP reference, often on a decal, instead of a next examination date. Since the 2012 amendments to the Convention, ACEP programmes must be reviewed at least every ten years, and the intervals between thorough examinations must not exceed those of the PES.

One consequence matters to every buyer of used equipment. An ACEP belongs to the owner, not to the box. When a shipping line or a leasing company sells a container out of its fleet, its ACEP no longer covers that unit. The new owner must have the container examined and marked with a next examination date under the PES before it travels internationally again.

Scope of the CSC

What a CSC examination checks, and what it does not

A CSC examination is a structural safety check. The examiner looks at the elements that carry loads when the container is lifted, stacked, lashed and racked at sea: corner posts, corner and intermediate fittings, top and bottom rails, the understructure and cross members, the door frame, door locking gear and the floor's ability to carry its rated load. Since 2012, the Convention also lists serious structural deficiencies, such as cracked or broken corner fittings or damaged load-bearing members, that allow authorised officers to stop a container until it is repaired.

What a CSC examination does not certify is just as important. It does not certify that the container is watertight, clean, odour-free, free of contamination or suitable for a given cargo. A container can carry a valid plate and still have a pinhole in the roof, a stained floor or a door seal that lets rain in. Those questions belong to the condition survey.

Covered: structural integrity for handling, stacking and transport; legibility and validity of the Safety Approval Plate.
Not covered: wind and water tightness, cleanliness, odour, floor contamination, cosmetic condition, suitability for food or sensitive cargo.

The condition survey

What a seaworthy or cargo worthy certificate is

"Seaworthy" and "cargo worthy" (CW) are trade terms for the same idea: a container that is structurally sound, wind and water tight, and fit to carry general cargo on an international sea voyage. Neither term appears in the Convention, which is why the certificate that supports them is a survey report rather than a regulatory document.

The report is issued by an independent marine surveyor or a certified container inspector after a physical inspection, inside and out. A serious report identifies the container by its ISO 6346 number, verified with the check digit, and records size and type, date of manufacture, the CSC plate details and next examination date or ACEP reference, the inspection date and place, the criteria applied, findings component by component, the result of a light test for wind and water tightness, photographs, and the surveyor's name and credentials.

Its conclusion is a grade or a pass/fail statement against the stated criteria. Some reports add recommended repairs; a container that fails can often be repaired and re-surveyed.

Container number with a valid ISO 6346 check digit, size and type.
CSC plate details: approval reference, manufacture date, next examination date or ACEP.
Inspection date, location (depot) and the criteria used.
Findings per component: panels, roof, floor, rails, posts, doors, gaskets, locking gear.
Light test result for wind and water tightness.
Photographs and the surveyor's identification.

Inspection criteria

"Cargo worthy" according to which standard?

Because cargo worthy has no legal definition, the criteria named in the report decide what it means. Three references are in common use.

IICL-6, the Guide for Container Equipment Inspection of the Institute of International Container Lessors, sets the condition in which leased containers must be returned. It is the strictest of the three and is used for leasing grades rather than for one-way or trading cargo worthy grades.

UCIRC, the Unified Container Inspection and Repair Criteria, defines cargo worthiness for operational containers. The Container Owners Association's Criteria for Cargo-Worthy (CCW) cover the same ground with slightly wider tolerances, intended to avoid repairs that do not affect cargo safety: for example, a dent in a corner post of up to 25 mm under CCW against 20 mm under UCIRC.

Two reports that both say "cargo worthy" can therefore describe different containers. Ask which criteria were applied, and make sure they match what your carrier or your buyer expects.

Side by side

CSC approval and seaworthy certificate compared

The two documents overlap on one point only: both look at the structure. Everything else differs.

Legal basis: the CSC is an international convention; the seaworthy certificate is a commercial survey with no legal definition.
Issued by: the Administration or a classification society for the approval, the owner's examiners for PES and ACEP; an independent surveyor or certified inspector for the seaworthy certificate.
Where it lives: the CSC is on the container, on the Safety Approval Plate; the seaworthy certificate is a separate report.
Question answered: is the structure safe to handle and transport; versus is this box in a condition fit for cargo at sea.
Validity: the CSC until the next examination date, or continuously under ACEP; the seaworthy certificate describes the container on the inspection date only.
Required by: carriers, terminals and port authorities check the CSC for any international movement; the seaworthy certificate is required by contract, by a buyer or by a carrier's own acceptance rules.
Grades concerned: any container in international use needs a valid CSC status; only cargo worthy, IICL and one-trip containers can obtain a seaworthy certificate.

Use cases

Which document do you need?

The answer depends on what the container will do next, not on how it was sold.

Export, shipper owned container (SOC) or one-way move: a valid CSC status is mandatory, and a cargo worthy condition is needed in practice. Ask for a recent survey report when the carrier, the consignee or a letter of credit requires one.
Buying used containers to resell for export: ask for both, unit by unit. Your buyers will ask you for them.
Containers bought out of a shipping line or lessor fleet: plan a PES examination and a next examination date, because the seller's ACEP no longer applies.
On-site storage, construction sites, farms and conversions: neither document is legally required. Wind and water tightness is what protects the contents, and a wind and water tight (WWT) grade is usually the economical choice.
Domestic road or rail moves without a sea leg: national road and rail rules apply; check with the haulier before assuming a CSC is irrelevant.

Timing

How long each one remains valid

A CSC status is valid until the next examination date on the plate, or for as long as the owner's ACEP covers the container. Check that date before the container leaves the depot, and leave a margin: a box that reaches its next examination date while still in the supply chain cannot be loaded until it has been re-examined.

A seaworthy certificate has no expiry date in law, but it only describes the container on the day of inspection. Every lift, every road trip and every week in a depot can change that condition. Buyers and carriers therefore look for a recent report, ideally made at the depot of release shortly before gate-out. A report several months old, or made at another location, proves little about the container you will receive.

Due diligence

Red flags when a seller offers "certified" containers

Certificates are easy to copy and easy to over-sell. Before paying, check that every document matches the container you are buying.

A certificate without a container number, or one certificate for a whole lot of containers.
A container number whose ISO 6346 check digit does not compute.
A "seaworthy certificate" offered with a wind and water tight or as-is container: these grades do not qualify.
A CSC plate that is missing, painted over, illegible or loose.
A next examination date already passed, or an ACEP decal from a previous owner presented as current coverage.
A survey report with no date, no location, no criteria or no surveyor identification.
Photographs that show a different door end, a different number or another depot.

Working with MG-Atlantic

What to specify when you request containers

For export, SOC or one-way use, state it in your request: the size and type, the grade (cargo worthy, one-trip or IICL), the CSC status you need (next examination date or examination before release), whether a survey report per unit is required, and by which criteria. Containers for storage are quoted on their wind and water tight condition.

MG-Atlantic trades and leases containers through depot partners worldwide and works as an independent operator. A precise request lets us check plate, grade and depot conditions per unit before release, instead of discovering a gap at the port.

Frequently Asked Questions

CSC and seaworthy certificates, answered

No. The CSC approval, shown on the Safety Approval Plate, confirms under an international convention that the container design is approved and that its structural examinations are up to date. A seaworthy or cargo worthy certificate is a commercial survey report describing the condition of one container on the day it was inspected.

An independent marine surveyor or a certified container inspector, after a physical inspection of the container against stated criteria such as UCIRC, the Container Owners Association's CCW or, for leasing grades, IICL-6.

Under the Periodic Examination Scheme, the first examination takes place no later than five years after manufacture and then at intervals of no more than 30 months. Containers under an Approved Continuous Examination Programme (ACEP) are examined at operational events instead and carry the ACEP reference on or near the plate.

Yes. A plate and an examination date can still be valid on a container whose condition no longer meets cargo worthy criteria. That is why a valid CSC alone does not prove a container is fit for export cargo.

The container must not be used in international transport until it has been re-examined and a new next examination date has been marked. Terminals and carriers can refuse it at gate-in.

No. An ACEP is approved for an owner's fleet. Once the container leaves that fleet, the new owner must arrange a periodic examination and mark a next examination date before using it internationally.

It has no legal expiry date, but it only describes the container on the inspection date. Buyers and carriers expect a recent report, ideally made at the release depot shortly before gate-out.

No. For on-site storage, construction or conversion, neither document is legally required. What protects the contents is wind and water tightness, which a WWT grade already provides.

It carries a recent CSC plate and its first examination falls within five years of manufacture. A survey is usually unnecessary, but a buyer or carrier may still ask for one, and photographs at release remain good practice.

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