Steel is heavy, long and hard on containers. Load it badly and you risk cargo damage, rejected containers, fines for overweight boxes or, worse, accidents. Good container loading for steel pipes, plates, fittings and flanges saves freight, protects goods and impresses buyers when they open the doors.

Steel "weighs out" before it "cubes out"

Most cargo fills a container's volume before reaching its weight limit. Steel is the opposite: you will usually reach the maximum payload long before the container looks full. Planning starts with weight, not space.

20ft vs 40ft: the key numbers

Typical figures for standard dry (general purpose) containers — always check the exact values with your shipping line, because they vary by container and carrier:

Point 20ft GP 40ft GP
Internal length about 5.9 m about 12.0 m
Internal width about 2.35 m about 2.35 m
Internal height about 2.39 m about 2.39 m
Max payload (container rating) roughly 25–28 tonnes roughly 26–27 tonnes

Because the payload of a 40ft is similar to a 20ft, steel usually ships in 20ft containers. A 40ft makes sense only for long items or lighter, bulky steel products.

Remember too that road weight limits at origin and destination may be lower than the container's rating. Check what can legally be trucked at the buyer's end before you plan maximum payload.

The 6-metre pipe problem

A 20ft container's internal length is about 5.9 m — shorter than a 6 m pipe. Exporters handle this by:

  • agreeing 5.8 m fixed lengths with the buyer,
  • shipping 6 m and 12 m lengths in 40ft containers (12 m pipes fit only just; 11.8 m is a safer length),
  • using open-top or flat-rack containers for long or oversized pieces,
  • shipping as break bulk for very long or heavy items.

Agree pipe length and container type at the quotation stage, not after production. Our guide to export pricing shows how freight choice affects your CFR/CIF price.

Special containers

  • Open top: loaded from above by crane; ideal for heavy coils, long bundles and machinery.
  • Flat rack: no side walls or roof; for oversize or very heavy pieces.
  • Coil-friendly loading: steel coils need cradles or saddles and special lashing because they concentrate weight.

Weight distribution

  • Spread weight evenly across the floor; avoid concentrating heavy crates in one area.
  • Keep the centre of gravity near the middle of the container, both lengthwise and sideways.
  • Use timber beams (dunnage) under heavy crates to spread point loads — container floors have limits on concentrated loads.
  • Never exceed the maximum payload marked on the container door.

Lashing, blocking and dunnage

Steel moves violently at sea if not secured. Good practice:

  • Bundle pipes tightly with steel strapping and protect ends with caps.
  • Use timber dunnage between layers and under bundles.
  • Block and brace cargo against walls with timber to stop movement.
  • Lash to container lashing points with steel strapping, wire rope or polyester lashing rated for the load.
  • Fill gaps with timber or airbags so nothing can slide.

Follow the IMO/ILO/UNECE CTU Code (Code of Practice for Packing of Cargo Transport Units), which most carriers and insurers refer to.

Protecting steel from damage and corrosion

  • Use end caps on bevelled pipes and flange face protectors.
  • Wrap stainless steel to prevent contact with carbon steel and timber contamination; see pickling and passivation.
  • Add desiccant bags or container dry liners against condensation ("container rain").
  • Use heat-treated, ISPM 15 marked timber for packing.

Our export packing guide covers crates, bundling and marking in detail.

VGM: verified gross mass

Under the SOLAS convention, every packed export container must have a Verified Gross Mass (VGM) declared by the shipper before loading on the vessel. VGM includes cargo, packing, dunnage and the container's tare weight. Containers without VGM will not be loaded. Get it by weighing the packed container or by an approved calculation method, and share it with your forwarder on time.

Photos and loading reports

Take photos at each stage: empty container, first layer, lashing, final load, door closing and seal number. Share them with the buyer. It reduces disputes and shows professionalism. Many importers now expect a loading report with every shipment.

Working with your forwarder

A good forwarder helps choose container types, books equipment, arranges VGM and advises on lashing. See how to choose a freight forwarder for steel shipments.

Frequently asked questions

How many tonnes of steel fit in a 20ft container?

Typically up to around 25–28 tonnes, depending on container rating, shipping line rules and road limits at origin and destination.

Can 6 m pipes go in a 20ft container?

Usually not, because the internal length is about 5.9 m. Use 5.8 m lengths, a 40ft container or special equipment.

What is VGM?

Verified Gross Mass is the total weight of the packed container, which the shipper must declare under SOLAS before loading.

Why does steel need dunnage?

Dunnage spreads heavy loads across the container floor, separates layers and helps secure cargo against movement.

Key takeaways

  • Steel reaches weight limits before space limits — 20ft containers are usually best.
  • 6 m pipes do not fit a standard 20ft; plan lengths and containers early.
  • Distribute weight, use dunnage and lash firmly following the CTU Code.
  • Declare VGM and document loading with photos.

Professional loading is something buyers notice the moment they open the doors — and it is a reason they come back.