Containers & Container Types

Most general cargo today moves in containers, and NAFL is emphatic that a forwarder must know container dimensions and characteristics cold — because advising clients and calculating how a shipment fits a box is daily work. Get the container choice or the cubic calculation wrong and cargo is left on the quay, or a second box is paid for needlessly.

The standard container and the TEU

The standard container is the twenty-foot (20’) box, and capacity across the industry is measured in multiples of it.

Dimensions and capacities — the numbers to know

NAFL gives the working figures for standard dry-cargo (DC) containers. These are the ones a forwarder quotes against:

	20’ Dry	40’ Dry
Internal length	5,898 mm	12,031 mm
Internal width	2,352 mm	2,352 mm
Internal height	2,393 mm	2,393 mm
Cubic capacity	~33.2 CBM	~67.7 CBM
Max gross weight	30,480 kg	30,480 kg
Tare (empty) weight	~2,300 kg	~3,840 kg
Payload	~28,180 kg	~26,640 kg

Two practical points NAFL draws from this table: a 40’ holds roughly double the volume of a 20’ but not double the weight payload (its own tare is heavier), so a 40’ is for bulky cargo, a 20’ for dense/heavy cargo. And the cubic figures (33.2 / 67.7 CBM) are exactly the numbers used in the stuffing calculations of Chapter 3.

The high cube and the 45’

The high-cube (HC) is a 40’ container about a foot taller (8’6” → 9’6” external) for extra volume — and NAFL notes that most 40’ boxes seen in the Middle East are high-cubes. The 45’ exists but is less common, as its extra length complicates stacking with standard 20’/40’ boxes.

Specialised container types

Beyond the standard dry box, NAFL covers the family of specialised units — each solving a particular cargo problem:

• Reefer (refrigerated) — carries its own electrically powered freezer unit; for perishables (meat, fish, fruit, dairy) needing temperature control throughout transit.
• Open-top — no solid roof (a tarpaulin instead); for out-of-gauge loads taller than the box, or top-loading with a crane (e.g. machinery).
• Flat rack — no roof and no sidewalls; strengthened lashing points; end-walls that fold down. For heavy, wide or awkward cargo (vehicles, aircraft engines, generators). Often preferred over open-top at 40’ for its much heavier payload. End-walls up = ISO flat rack; both down = platform flat.
• Open-side — opens along the side for oversized or awkward loading.
• Dry bulk — for grain, powder and granular cargo loaded through hatches.
• Half-height — for exceptionally heavy, dense cargo (steel tubes, pipes) where weight, not volume, fills the box.
• Tank (ISO tank) — a stainless-steel tank built into a 20’ frame for carrying liquids, chemicals and gases in bulk; reusable, robust, and the standard for hazardous and high-value liquids (insulated/heatable versions exist). The handle-like-a-container way to move a liquid in bulk (Chapter 17).
• Flexitank — a large disposable bladder fitted inside an ordinary 20’ dry box, turning it into a one-way carrier for non-hazardous bulk liquids such as edible and base oils (Chapter 17). Cheap, single-use, and never used for dangerous goods.

Container anatomy and safe stuffing

A forwarder should recognise the structural parts, because they explain how a box is lifted and loaded safely. NAFL labels them on a construction diagram; the ones that matter in practice:

• Corner castings (corner fittings) — the eight reinforced corners. Gantry-crane spreader bars and ship/chassis twistlocks lock into these to lift and secure the box. They are the only points designed to take the lifting and stacking loads.
• Corner posts — the vertical members at each corner that carry the stacking weight of the containers above (boxes are stacked many-high on deck and in the yard).
• Cross members — the transverse under-floor beams that carry the cargo’s weight. Heavy point-loads must be spread across several of them.
• Top and bottom side rails, end rails, side posts — the frame.
• Lashing points — fittings on the floor and side walls to secure (lash) the cargo inside; NAFL notes good containers provide ample lashing points on floor and sidewalls.
• Fork pockets — slots underneath so a heavy-duty fork-lift can lift the box (item 12 on NAFL’s diagram).
• Door gasket, locking bars, locking-bar handles/keepers — the weather-tight, lockable door gear.

NAFL’s central stuffing rule:

(The full set of stuffing, restraint and load-distribution techniques — shoring, lashing, wedging, locking — is covered with packing in Chapter 22.)

What to take from this chapter

1. The 20’ box = 1 TEU; capacity and ships are measured in TEU.
2. Know the numbers: 20’ ≈ 33.2 CBM, 40’ ≈ 67.7 CBM, max gross ~30.5 t; 40’ is for bulk, 20’ for weight.
3. Match cargo to the right type — reefer, open-top, flat rack, dry-bulk, half-height.
4. Safe stowage = immovable stow + even weight distribution; heavy low, load spread over cross members.