Bühlmann decompression algorithm

The Bühlmann decompression algorithm is a mathematical model (algorithm) of the way in which inert gases enter and leave the human body as the ambient pressure changes.^[1] It is used to create Bühlmann tables. These are decompression tables which allow divers to plan the depth and duration for dives and show decompression stops when necessary.

The algorithm was developed by Swiss physician Dr. Albert A. Bühlmann, who did research into decompression theory at the Laboratory of Hyperbaric Physiology at the University Hospital in Zürich, Switzerland.^[2][3] The results of Bühlmann's research that began in 1959 were published in a 1983 German book whose English translation was entitled Decompression-Decompression Sickness.^[1] The book was regarded as the most complete public reference on decompression calculations and was used soon after in dive computer algorithms.

Principles

Building on the previous work of John Scott Haldane and Robert Workman,^[4][5] and working off funding from Shell Oil Company,^[6] Bühlmann designed studies to establish the longest half-times of nitrogen and helium in human tissues.^[1] These studies were confirmed by the Capshell experiments in the Mediterranean sea in 1966.^[6][7]

The naming convention he used to describe his algorithms, for example, ZH-L16, comes from Zürich (ZH), limits (L) and the number of tissue compartments or M-value sets used (16).

Tables

Max Hahn first used Bühlmann's algorithm to develop dive tables for the Swiss Underwater Sport Association. In 1987, the SAA Bühlmann System was developed by Bob Cole. This system used the dive tables and a set of rules so that people could dive safely and stay below their no-decompression limit.^[8] The tables are still used today and are very popular; many dive computers still use the ZHL-8 algorithm and many tables are based on the ZHL-16 algorithm. These calculations also include considerations for repetitive and altitude diving.^{[1][9][10][11][12][13]}

References

Further reading

External links

Many articles on the Bühlmann tables are available on the web.

• Chapman, Paul (November 1999). "An Explanation of Professor A.A. Buehlmann's ZH-L16 Algorithm". New Jersey Scuba Diver. Retrieved 20 January 2010.  – Detailed background and worked examples
• Decompression Theory: Robert Workman and Prof A Bühlmann. An overview of the history of Bühlmann tables
• Stuart Morrison: DIY DECOMPRESSION (2000). Works through the steps involved in using Bühlmann's ZH-L16 algorithm to write a decompression program.

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