Introduction
Floor Load Capacity limit is usually a factor unknown to the shipper. However, it is useful to understand this concept, so that the packaging can be optimised. Air freight packaging must be strong enough to withstand fast operational procedures. Forklifts, pallet-jack handling, moving, sliding, vibrations etc are all factors that need to be taken into account. Waterproofing of the package is an additional measure that may be added to the checklist. However, one important point, which should not be forgotten is the floor load tolerance or floor load capacity limit. This factor is of extreme importance when pallets with chocks are used in air freight packaging.
Why Is Floor Load Capacity Limit Important
Freight forwarding by air uses unit load devices (ULD), which are mostly made of light weight aluminium. Although the metal is known for its tensile strength, it is not fully resistant to damage. As per the air freight regulations certain amount or type of damage can disqualify a ULD from being used in transport. Missing rivets, deep dents or ripped sides etc. can disqualify a ULD.
Air freight packaging referred to here includes the carrier pallet. This may be made of hard board, wood, plastic or any other permitted material.
Understanding Air Freight Basics
Floor load capacity limit is the maximum permissible load per square meter. The standard used by Lufthansa is 2000 Kg per square meter. An amount of weight higher than this amount is assumed to damage the ULD and hence endanger the safety of the aircraft. A damaged ULD gives rise to the risk of freight moving while in flight, which in turn can set off destabilising the other freight on board.
Since the maximum permissible load per square meter has been set, we need to calculate the area of the footprint (the area occupied by the freight). In order to make the calculation understandable, the simplest example of a pallet with chocks is used below. The chocks (feet) of the pallet apply a concentrated weight on a very small area. Calculating the footprint is, to put in other words, finding the contact area.
The contact area in square meters is then multiplied with the maximum permissible load (2000 Kg). The result is the maximum weight of the freight.
The Calculation
We shall consider a pallet with four chocks, with each chock measuring 8 cm (both length and width).
1 square meter = 100 cm x 100 cm = 10,000 square centimetre
Maximum permissible capacity for 1 sq. meter = 2000 Kg
One chock = 8 x 8 cm = 64 sq. cm
Total area of four chocks = 4 x (8 x 8) = 256 sq. cm
(Maximum permissible weight / 10,000 sq. cm) x 256 sq. cm = ?
(2000 x 10,000) x 256 = 51.2
In this case the total weight of the package (pallet plus the piece of freight) on it should not be more than 51.2 kg. Any load on the top of the freight will mean crossing the load tolerance limit.
You, as a shipper, are not required to know the calculation. The article is to help you plan your air freight packaging with the freight forwarder and airlines in mind.
Air Freight Planning
- Try to avoid pallets with chocks, especially conical chocks. The amount of weight per contact area of a conical chock is greater than that of a chock that is flat.
- Use pallets with chocks resting on strips making the full length or width of the pallet. This will help distribute the weight over a large area
- Even distribution of weight within the crate/carton with dunnage preventing the movement of the content.
- Wobbly content shifts weight and creates possibility for damage to content
- Avoid overhangs! Freight should occupy only the area of the pallet and not project out of the rims.
- If wooden pallets are to be used, make sure they are IPPC standard and the logo should be visible from the outside (embossed on the side)
- Air freight packaging must be strong enough and air worthy. Waterproofing is not mandatory but is certainly recommended.
Resources Centre
Anybody needing help or advice to plan air freight Please get in touch using the contact form. However, consultation with your freight forwarder/air cargo agent cannot be stressed enough.
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References for air freight
Air cargo – Wikipedia, the free encyclopedia
Air cargo is any property carried or to be carried in an aircraft. Air cargo comprises air freight, air express and airmail. Contents. [hide]. 1 Aircraft types; 2 History.