Several measures of these devices of load unitization exist. The most restrictive are:

The maximum length of the loads is not limited the pallets size or containers. 

AThe embarkment possibilities exceed that length, in the measure in that the width allows the transfer of the volume inside of the space of the basement, whose width can exceed 400cm.

I weigh maximum for volume:   

The aerial companies establish, for itself, the limits for weight concentration for area. As the loads are embarked in pallets or containers, the weight concentration is distributed by the area of these devices.

 
However, the manufacturers' recommendation is for a maximum weight of 765kg/m² in basements of passengers' airplanes.