VPM-B model information

Home Support FAQ and online help Download Commercial Diver Registration VPM-B details VPM model in detail Email Copyright©2008 HHS Software Corp.		The VPM-B model VPM-B is a revision by Erik Baker to his original work and the model described below. The change was to include Boyles Law compensation to the ascent gradients that determine ceilings and times of stops. This one additional set of calculations in the model, corrected a number of concerns about plans from the Original model. The output from a VPM-B profile is a plan that retains both deep stops, and modest amount of time in the shallow areas. A significant amount of diver feedback has confirmed that the VPM-B model is valid across a wide range of dive profiles. From a gentle NDL dive, to a normal double tank deco dive, or a deep CCR dive. VPM-B is the newest and most accurate bubble model available. The VPM-B model on it's own, produces consistent decompression plans for the entire range of dives, and accurately intercepts the NDL limits as well. VPM-B does not require any modifiers or factors or other mathematical hacks on the input parameters, etc. i.e. no GF's or pfac, bfac, factors, or other trimming methods to arrive at the "right" result. Brief history of the VPM. 1974 - 1981 U of Hawaii Series of research papers (15+) by Yount,D.E. Hoffman,D.C Kunkle,T.D. Strauss, R.H. D’Arrigo, J.S., Ingle, F.W., Yeung, C.M., and Beckman, E.L. Yeung, C.M. Paganelli, C.V., Gillary, E.W., Research paper titles include Bubble formation, Bubble nucleation in supersaturated fluids, Isobaric bubble growth, Skins of varying permeability, Determination of the radii of gas cavitation nuclei, Application of a bubble formation model to decompression sickness, 1982 - 1984 Research papers by Yount,D.E. Hoffman,D.C SGillary, E.W. Titles: ...evolution, generation, and regeneration of gas cavitation nuclei, ...use of a cavitation model to calculate diving tables, ...microbubble fission in surfactant solutions, ...microscopic investigation of bubble formation nuclei 1986 Varying Permeability Model (VPM) - Yount and Hoffman VPM tables - Yount and Hoffman 1990 Eric Maiken starts working the VPM code, and start formatting his own VPM program made with BASIC. 1992 Eric Maiken starts diving the model in the 130-220ft depth range, with O2 decompression, and progressing to weak trimix to 250 ft. 1994 Eric Maiken distributes his BASIC VPM program, to divers / researchers. Program was multi-level and nitrox mix capable. 1995 The Yount and Hoffman (1986) VPM algorithm was made freely available to programmers and researchers at the tek95 diving technology conference. Eric released his VPM program code at this time in the VBA format, with an Excel spreadsheet front end. Eric Maiken reported his experiences with non Buhlmann based deco. The text from this conference "Bubble Decompression Strategies" later became an article in Deep Tech magazine by Win Remly and Curt Bowen. 1997 Eric Maiken's program now distributed in Mathematica and full trimix capable. 1998 The VPM List (later named DecoList) started by Rob Murray which attracted 200 + members initially, to discuss and test progress in the work on the Eric Maiken's VPM model code. David Yount joins in discussions, pleased to see his research work in use. Erik Baker (developer of the ¹Gradient Factor model) joins the project. Many well known researchers, tech divers and industry leaders and others contribute to the progress of the VPM model. 1999 VPM development progresses with David Yount, Eric Maiken, Erik Baker working on repetitive diving, and a paper for the Smithsonian conference on reverse dive profiles. 2000 David Yount, UH physics and astronomy professor, dies in April at age 64. The core VPM algorithm was finalized in June, 2000 when David Yount's preliminary algorithm for multiple VPM dives was presented as a poster (.ppt format) at the UHMS conference in Stockholm. At this time, the algorithm had advanced beyond Yount/Hoffman's 1986 paper to include multiple inert gases and switches, new dynamics in calculating the critical radius (for example, ascent and descent influence on critical radii), as well as tracking the effects of multi dives. Erik Baker's Fortan VPM program codes finalized (public domain) with contributions from many involved in the past years. This becomes the standard implementation of VPM models. 2001 Ross Hemingway (developer of the ²ZPlanner program) adapts the VPM Fortan code by Erik Baker from its DOS console state, into a full Windows program. The new program is named V-Planner and is released as a freeware in July. 2002 VPM use in recreational tech diving grows. Model is adapted for use with CCR planning. Diver feedback and documented experiences grow. Initial data suggests the model is valid, but is somewhat range bound. Erik Baker starts work on a revision to the original model (described above). This results in a change to calculating ascent ceilings by including a Boyles Law compensation. Revised model is named VPM-B. 2003 February: V-Planner with VPM-B released at the NAUI Deep Stop conference. IANTD includes VPM-B tables into all new training courses. VPM enters commercial work as an approved decompression program with the Danish Maritime Authorities. V-Planner program further developed to include many of the current tech diving planning features and practices. 2004 V-Planner and VPM/B is now widely used by tech divers in the USA & Canada, and continues to grow throughout the world. Dave Shaw sets world record CCR depth of (270m at Boesmansgat cave) with VPM-B. See also... VPM References, Eric Maiken's VPM decompression site (bubble model explanations). 1. Gradient Factors are in now use with many Bulhmann based algorithims, including DecoPlanner. 2. ZPlanner was a wrapper around the Zplan DOS program by the late Will Smithers.

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The VPM-B model

VPM-B is a revision by Erik Baker to his original work and the model described below. The change was to include Boyles Law compensation to the ascent gradients that determine ceilings and times of stops. This one additional set of calculations in the model, corrected a number of concerns about plans from the Original model.

The output from a VPM-B profile is a plan that retains both deep stops, and modest amount of time in the shallow areas. A significant amount of diver feedback has confirmed that the VPM-B model is valid across a wide range of dive profiles. From a gentle NDL dive, to a normal double tank deco dive, or a deep CCR dive.

VPM-B is the newest and most accurate bubble model available. The VPM-B model on it's own, produces consistent decompression plans for the entire range of dives, and accurately intercepts the NDL limits as well. VPM-B does not require any modifiers or factors or other mathematical hacks on the input parameters, etc. i.e. no GF's or pfac, bfac, factors, or other trimming methods to arrive at the "right" result.

Brief history of the VPM.

1974 - 1981 U of Hawaii

Series of research papers (15+) by Yount,D.E. Hoffman,D.C Kunkle,T.D. Strauss, R.H. D’Arrigo, J.S., Ingle, F.W., Yeung, C.M., and Beckman, E.L. Yeung, C.M. Paganelli, C.V., Gillary, E.W.,
Research paper titles include Bubble formation, Bubble nucleation in supersaturated fluids, Isobaric bubble growth, Skins of varying permeability, Determination of the radii of gas cavitation nuclei, Application of a bubble formation model to decompression sickness,

1982 - 1984

Research papers by Yount,D.E. Hoffman,D.C SGillary, E.W.
Titles: ...evolution, generation, and regeneration of gas cavitation nuclei, ...use of a cavitation model to calculate diving tables, ...microbubble fission in surfactant solutions, ...microscopic investigation of bubble formation nuclei

1986

Varying Permeability Model (VPM) - Yount and Hoffman
VPM tables - Yount and Hoffman

1990

Eric Maiken starts working the VPM code, and start formatting his own VPM program made with BASIC.

1992

Eric Maiken starts diving the model in the 130-220ft depth range, with O2 decompression, and progressing to weak trimix to 250 ft.

1994

Eric Maiken distributes his BASIC VPM program, to divers / researchers. Program was multi-level and nitrox mix capable.

1995

The Yount and Hoffman (1986) VPM algorithm was made freely available to programmers and researchers at the tek95 diving technology conference. Eric released his VPM program code at this time in the VBA format, with an Excel spreadsheet front end. Eric Maiken reported his experiences with non Buhlmann based deco.

The text from this conference "Bubble Decompression Strategies" later became an article in Deep Tech magazine by Win Remly and Curt Bowen.

1997

Eric Maiken's program now distributed in Mathematica and full trimix capable.

1998

The VPM List (later named DecoList) started by Rob Murray which attracted 200 + members initially, to discuss and test progress in the work on the Eric Maiken's VPM model code. David Yount joins in discussions, pleased to see his research work in use.
Erik Baker (developer of the ¹Gradient Factor model) joins the project.
Many well known researchers, tech divers and industry leaders and others contribute to the progress of the VPM model.

1999

VPM development progresses with David Yount, Eric Maiken, Erik Baker working on repetitive diving, and a paper for the Smithsonian conference on reverse dive profiles.

2000

David Yount, UH physics and astronomy professor, dies in April at age 64.
The core VPM algorithm was finalized in June, 2000 when David Yount's preliminary algorithm for multiple VPM dives was presented as a poster (.ppt format) at the UHMS conference in Stockholm. At this time, the algorithm had advanced beyond Yount/Hoffman's 1986 paper to include multiple inert gases and switches, new dynamics in calculating the critical radius (for example, ascent and descent influence on critical radii), as well as tracking the effects of multi dives.
Erik Baker's Fortan VPM program codes finalized (public domain) with contributions from many involved in the past years. This becomes the standard implementation of VPM models.

2001

Ross Hemingway (developer of the ²ZPlanner program) adapts the VPM Fortan code by Erik Baker from its DOS console state, into a full Windows program. The new program is named V-Planner and is released as a freeware in July.

2002

VPM use in recreational tech diving grows. Model is adapted for use with CCR planning. Diver feedback and documented experiences grow. Initial data suggests the model is valid, but is somewhat range bound. Erik Baker starts work on a revision to the original model (described above). This results in a change to calculating ascent ceilings by including a Boyles Law compensation. Revised model is named VPM-B.

2003

February: V-Planner with VPM-B released at the NAUI Deep Stop conference.
IANTD includes VPM-B tables into all new training courses.
VPM enters commercial work as an approved decompression program with the Danish Maritime Authorities.
V-Planner program further developed to include many of the current tech diving planning features and practices.

2004

V-Planner and VPM/B is now widely used by tech divers in the USA & Canada, and continues to grow throughout the world.
Dave Shaw sets world record CCR depth of (270m at Boesmansgat cave) with VPM-B.

See also... VPM References, Eric Maiken's VPM decompression site (bubble model explanations).

1. Gradient Factors are in now use with many Bulhmann based algorithims, including DecoPlanner.
2. ZPlanner was a wrapper around the Zplan DOS program by the late Will Smithers.