Varying Permeability Model

The Varying Permeability Model, Variable Permeability Model or VPM is an algorithm that is used to calculate the decompression stops needed for a particular dive profile. It was developed by D.E. Yount and others for use in professional diving 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 Hawaii to calculate diving decompression tables.

The VPM presumes that microscopic bubble nuclei always exist in water and tissues that contain water. Any nuclei larger than a specific "critical" size, which is related to the maximum dive depth (exposure pressure), will grow upon decompression (when the diver ascends again). The VPM aims to minimize the total volume of these growing bubbles by keeping the external pressure large, and the inspired inert gas partial pressures low during decompression. The model depends on the assumptions that different sizes of bubbles exist within the body; that the larger bubbles require less reduction in pressure to begin to grow than smaller ones; and that fewer large bubbles exist than smaller ones. These are used to construct an algorithm that provides decompression schedules designed to allow the larger, growing bubbles to be eliminated before they can cause problems.[2][3]


This bibliography list was compiled by E.B. Maiken and E.C. Baker as reference material for the V-Planner web site in 2002.[4]

Primary Modeling Sources

  • Yount, D.E. and Hoffman, D.C. 1984. Decompression theory: A dynamic critical-volume hypothesis. In: Bachrach A.J. and Matzen, M.M. eds. Underwater physiology VIII: Proceedings of the eighth symposium on underwater physiology. Undersea Medical Society, Bethesda, 131-146.
  • Yount, D.E.; Hoffman, D.C. (1986). "On the use of a bubble formation model to calculate diving tables". Aviat Space Environ Med. 57 (2): 149–156. ISSN 0095-6562. PMID 3954703.
  • Yount, D.E. and Hoffman, D.C. 1989. On the use of a bubble formation model to calculate nitrogen and helium diving tables. In: Paganelli, C.V. and Farhi, L.E. eds. Physiological functions in special environments. Springer-Verlag, New York, 95-108.
  • Yount, D.E., Maiken, E.B., and Baker, E.C. 2000. Implications of the Varying Permeability Model for Reverse Dive Profiles. In: Lang, M.A. and Lehner, C.E. (eds.). Proceedings of the Reverse Dive Profiles Workshop. Smithsonian Institution, Washington, D.C. pp. 29–61.

VPM Research and Development Sources

VPM Dive Planning Software

  • V-Planner: VPM-B & VPM-B/E, VPM-B/FBO.[4]
  • MultiDeco: VPM-B & VPM-B/E, VPM-B/FBO, ZHL-B, ZHL-C, GF, and GFS.[5]
  • Ultimate Planner: VPM-B, VPM-B/U, VPM-B (Dec-12), VPM-B/U (Dec-12), ZHL-B, ZHL-C, ZHL-D, GF and GF/U.[6]
  • DecoPlanner: VPM-B.[7]
  • HLPlanner: VPM-B.[8]
  • JDeco: VPM-B.[9]
  • PalmVPM: VPM.[10]
  • DivePlan: VPM.[11]
  • Baltic Deco Planner: VPM-B.[12]
  • Subsurface: VPM-B.[13]

VPM Dive computers

  • V-Planner Live: VPM-B & VPM-B/E.[14]
  • MultiDeco-X1: VPM-B & VPM-B/E, VPM-B/FBO, ZHL-C, GF, and GFS.[15]
  • MultiDeco-DR5: VPM-B & VPM-B/E, VPM-B/FBO, ZHL-C, GF, and GFS.[16]
  • Shearwater Research Predator, Petrel, Perdix and NERD models: GF, VPM-B plus GFS.
  • RATIO Computers: iX3M series and iDive (Tech and Reb) series VPM-B and ZHL16-B.[17]
  • TDC-3 with MultiDeco-TDC: VPM-B & VPM-B/E, VPM-B/FBO, ZHL-C, GF, and GFS.[18]

See also

  • Decompression (diving)  The reduction of ambient pressure on underwater divers after hyperbaric exposure and the elimination of dissolved gases from the diver's tissues
  • Reduced gradient bubble model  An algorithm by Bruce Wienke for modelling inert gases leaving the body during decompression in mixed dissolved and bubble phases
  • Bühlmann decompression algorithm  Algorithm for modelling of inert gases entering and leaving body tissues in solution as pressure changes


  1. Yount, DE (1991). "Gelatin, bubbles, and the bends". In: Hans-Jurgen, K; Harper Jr, DE (Eds.) International Pacifica Scientific Diving... 1991. Proceedings of the American Academy of Underwater Sciences Eleventh Annual Scientific Diving Symposium held 25–30 September 1991. University of Hawaii, Honolulu, Hawaii. Retrieved 2011-10-14.
  2. Bonuccelli, Corrado (10 March 2004). "Calculating deco schedule with VPM" (PDF). Retrieved 8 June 2016.
  3. Watts, Kevin (19 March 2007). "VPM For Dummies". Rebreather World. Retrieved 8 June 2016.
  4. "V-Planner dive decompression planning software". HHS Software. Retrieved 8 June 2016.
  5. "MultiDeco VPM & VPM-B & VPM-B/E & ZHL GF dive decompression software for technical divers".
  6. "Tech Diving Mag - Free online technical diving magazine - Ultimate Planner".
  7. "DecoPlanner". Archived from the original on 10 January 2006.
  8. "HLPlanner". Archived from the original on 2008-03-15. Retrieved 2008-04-16.
  9. "JDeco - Dive Decompression Software for JAVA Mobile Devices (Buhlmann and VPM-B)".
  10. "Yahoo! Groups - PalmVPM".
  11. Roach, Greg. "DivePlan - Decompression software for SymbianOS".
  12. Olsen, Eskil. "baltic deco planner - iPhone deco planning app".
  13. Willem Ferguson; et al. "13.2.2. Non-recreational open circuit dives, including decompression". Subsurface 4.5 User Manual. Retrieved 10 November 2016.
  14. "V-Planner Live VPM-B, VPM-B/E dive deco computer firmware".
  15. "MultiDeco-X1 VPM-B VPM-B/E ZHL-GF dive computer firmware".
  16. "MultiDeco-DR5/DRX VPM-B VPM-B/E ZHL-GF dive computer firmware".
  17. "Ratio Dive Computers".
  18. "Technical Dive Computers TDC-3".
This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.