Swell & Void Percentage,
Load Factors

Definitions:

Swell: The percentage of original volume that a material increases when it is removed from its bank state and becomes “loose.” When excavated, the material breaks up into different size particles that do not fit together, creating voids that reduce the weight per volume. For example, to hold the same weight of one cubic meter/yard of material, it takes 30 percent more volume (1.3 times) after excavation if the swell is 30 percent.

Load Factor: The ratio of the loose volume to the bank volume. Since most contracts are paid in bank volume, load factors are useful for converting the loose volume moved into a bank volume measurement.