Behaviour in USC Assay 2026​.3 and on

For consistency and to avoid confusion, volume expansion is expressed as a proportion of the crude volume before expansion, not as a proportion of the product volume after expansion. Equivalently, volume expansion refers to a proportional increase in volume, rather than a proportional decrease in density (although the two are closely related).

Equation 6 is therefore replaced by:

(Equation 7)

Expressed in terms of density, the revised definition of volume expansion is:

(Equation 8)