Unitisation
"Unitisation" is based upon the theory that all shippers should pack their cargo so it may be moved and handled entirely by mechanical equipment, throughout the distribution network. This practice reduces the need for labour, the handling of boxes, and the amount of damage. Also, it allows for faster loading and unloading by transportation equipment, more efficient distribution centre operations and a reduced level of pilferage. The reduced costs of the distributor in terms of labour and time often result in cost discounts for the exporter.
The ‘primary unit load’ is a standard ISO container, approximately 8' wide and 8'6 or 9’6 high, and one of 3 standard lengths (20', 40’ and 45').
The most common unit load is the pallet, built up, perhaps, from separate packages in the form of a rectangular block, handled as a single lot and capable of being stacked onto other similarly palletised unit loads.
The most common pallet sizes are 1200 mm x 1000 mm (CP1), 1200 mm x 800 mm (Euro), 1160x1160 (Australia) 1100 x 1100 (Japanese). The 48 x 40 inches (1219 mm x 1016 mm), as used in the United States, is comparable to the 1200 mm x 1000 mm pallet and integrates very well into the metric system.
It is wrongly assumed that pallets fit efficiently into standard containers. They don’t. Most pallets are loaded into containers using a pin-wheel configuration.
Pinwheel or pin-wheeling: refers to a method for loading trailers where you alter the direction of every other pallet. Basically you use pin-wheeling when the depth of the pallet is longer than half the container width, but the depth plus the width is less than the container width.
Straight loading: The SeaCell2 allows allow two pallets to be loaded side by side with clearance space between the pallets and the container. This is the quickest method of loading pallets and makes maximum use of the containers internal width
Not having to Pin-wheel means that in some cases 20% more pallets can be loaded into a SeaCell than a standard container.
Standards for packages
The International Standard Organisation (ISO) gives a series of dimensions for rigid rectangular packages based on a standard plan dimension or module of 600 x 400 mm. This is the external size of a package unit when fully loaded (including 'bulge'). No plus tolerance is allowed, although a minus tolerance of up to 10 mm is accepted.
Both the OECD and MUM standards have pallet size 1200 mm x 1000 mm as a standard unit and derive the sub-multiples from these sizes. The OECD and MUM standards are less comprehensive than the ISO standard.
Recommended sizes in mm for OECD and MUM standards are:
|
OECD |
MUM |
| Pallet size (mm) |
1200 x 1000 |
1200 x 1000 |
|
1200 x 800 |
- |
| Box size (mm) |
- |
600 x 500 |
|
600 x 400 |
600 x 400 |
|
- |
500 x 400 |
|
500 x 300 |
500 x 300 |
|
400 x 300 |
400 x 300 |