Strapping inside a container versus lashing: what each one does

Strapping and lashing are often used as if they meant the same thing. On the packing floor they do not, and the difference decides whether a container arrives with its cargo where it was packed. The IMO/ILO/UNECE Code of Practice for Packing of Cargo Transport Units, known as the CTU Code, keeps the two jobs apart. In September 2019 it is the joint IMO, ILO and UNECE guidance on the subject, published as MSC.1/Circ.1497 in December 2014. The IMO describes it as a non-mandatory global code of practice.

Two jobs with different vocabularies

Strapping makes a unit. The code’s definitions describe unitized cargo as items arranged so they can be handled as a unit, for example by banding them securely together, and an overpack as packages stacked on a pallet and secured by strapping, shrink-wrapping or stretch-wrapping.

Securing keeps the unit in place. Annex 7, section 4.1.3, sets out three principles: direct securing, which transfers forces straight to the container by blocking, lashings, shores or locking devices; friction securing, where top-over lashings use pre-tension to press the cargo down and raise friction; and compacting by bundling, strapping or wrapping. The code calls the third an auxiliary measure that should always be combined with direct or friction securing.

	Unit strapping	Cargo securing
Purpose	Hold packages together as one unit	Stop the unit sliding, tipping or shifting in the container
Attached to	The unit itself	The container structure, through blocking or lashing points
Strength language	Strap break strength and joint performance	Maximum securing load (MSL) or labelled lashing capacity of the arrangement
Typical tools	Strapping tools and closures	Timber, dunnage bags, lashings with tensioners or buckles

Why a well-strapped pallet still needs securing

The CTU Code sets out the accelerations a unit must withstand. For sea transport in sea area A, the table in chapter 5 uses 0.3 g lengthways and 0.5 g sideways; for sea area C, 0.4 g and 0.8 g. Chapter 5.4 adds that the mass of the cargo, even with a high friction coefficient, does not sufficiently secure it, because vibration can move it.

A strapped pallet is a block, but nothing in its strapping connects it to the container. If there are gaps, the block can slide and strike the walls or other cargo. Annex 7 asks for gaps to be filled and, where items have poor coherence or tilting stability, for batches of items to be hooped or strapped with steel or plastic tape or sheeting. That strapping improves the block. It still does not hold the block in place.

Where strap does become securing

Strap can play a securing role, but the rules then change:

• Steel band. Annex 7, paragraph 2.4.16, notes that steel band is mostly used to unitize packages, but in sea transport is also used to tie packages down to flatracks, platforms or roll-trailers. It cannot be re-tensioned, and the code advises against using it for lashing on open units, where a broken band could hang outside.
• Web lashing systems. Paragraphs 2.4.18 and 2.4.19 describe modular systems of ready-made web lashings for general purpose containers, connected to the container’s lashing points and pre-tensioned with buckles and a tensioning tool. The number of lashings is to be calculated from the cargo mass, the MSL of the lashings, the lashing angle, the friction factor, the mode of transport and the MSL of the lashing points.

In both cases the capacity of the whole arrangement matters: strap or web, buckle or seal, and the anchor point. A woven strap and buckle chosen to bundle crates does not become a rated lashing because it is attached to a lashing ring. If strap and closures are to secure cargo, ask for documented capacity for that exact combination and calculate the number needed.

Do not forget the road leg

A container often travels by road at each end of the voyage. Under Directive 2014/47/EU, which Member States have applied from 20 May 2018, roadside inspectors may check whether cargo is secured so that it does not interfere with safe driving or put life, health, property or the environment at risk. A container packed for the sea leg also has to suit braking and cornering on the road.

Responsibility sits with the shipper

Chapter 4 of the CTU Code states that, although the carrier delivers under the contract of carriage, the shipper should deliver cargo that is safe for transport and remains responsible for deficiencies caused by poor packing and securing. A buyer who specifies packing for a supplier’s shipment should therefore specify both jobs: how units are strapped and how they are secured.

A planning checklist

1. Strap each unit so it holds together through handling, using strap and closures suited to its mass and edges.
2. Plan the stow to keep gaps small and fill the rest with dunnage or blocking.
3. Decide which units need lashing, and with what rated equipment.
4. Check the container’s lashing points and their capacity.
5. Record the method, with photographs, for the receiving site.

For unit strapping with woven strap and galvanized wire buckles, share the crate or pallet details through the enquiry page; strength values and any securing capacity remain on request and specific to the combination proposed.