Varying Permeability Model

The Varying Permeability Model, Variable Permeability Model or VPM is an algorithm that is used to calculate the decompression needed for ambient pressure dive profiles using specified breathing gases. It was developed by D.E. Yount and others for use in professional and recreational diving. It was developed to model laboratory observations of bubble formation and growth in both inanimate and in vivo systems exposed to pressure.^[1] In 1986, this model was applied by researchers at the University of Hawaiʻi to calculate diving decompression tables.^{[citation needed]}

Several variations of the algorithm have been used in mobile and desktop dive planning software and om dive computers.