Bühlmann decompression algorithm

The Bühlmann decompression algorithm is a family of models, developed by the Swiss physician Albert A. Bühlmann, for calculating how inert gases such as nitrogen and helium enter and leave a diver's body as the surrounding pressure changes. It follows the Haldane tradition, treating the body as several parallel tissue compartments that take up and release dissolved gas exponentially, and it uses Haldane's or Schreiner's formula for gas uptake. Its distinctive feature is that safe dissolved gas levels are set by a linear limit on tolerated pressure, a critical difference, rather than by a critical ratio as in earlier work. Bühlmann began the research in 1959 at the Laboratory of Hyperbaric Physiology at the University Hospital in Zürich, and published the results in a German book in 1983. Different parameter sets, named ZH-L followed by a number, such as ZH-L 16 with its A, B and C variants, are used to produce decompression tables and in dive computers, where they give no-decompression limits and decompression schedules.