Decompression practice
A decompression or Austauchtabelle (abbreviated also called deco table ) is used to determine in order to comply with the emergence of decompression. Decompression time is calculated or read depending on the maximum depth reached, the basic time and any residual saturation with nitrogen in body tissues of previous dives ( Repetitive dives and the surface breaks). If recommended by the Decompression decompression and other limits disregarded so threatens a potentially fatal decompression sickness.
Tables exist for different breathing gas mixtures (air, Nitrox, Trimix, Heliox, etc.), also separately for sea level ( 0-300 m or 0-700 m) and mountain dives ( about 300 or 700 m). For saturation dives and mixed gas exchange special calculation procedures are required.
History
Getting tables and Dekompressionsregeln built during the first helmet diving and caisson accidents. The medical and physical principles have since remained the same, only the experience and wealth of knowledge has been greatly expanded. Over time originated different decompression models. Based on practical experience, developed with decompression chamber rides and various other medical and physical tests and experiments, for decompression and tissue saturation algorithm, these mathematical models form the basis of all current decompression tables. Over time, the models have been continuously refined, which is why numerous tables that were created with some of instructional alignment.
Known decompression
- U.S. Navy, one of the oldest and best-known tables
- Bühlmann, 86, 89, etc., of Albert Bühlmann
- Bühlmann -Hahn
- Hahn- tables, for example Deco 92 and Deco, 2000 by Max Hahn
- COMEX (the French diving company ), for example CX04
- French Navy, for example, MN78, MN90
- Dräger, Haldane (if known only historically )
- Tables of associations and individual companies: PADI ( RDP: Recreational Dive Planner ), NAUI, Baracuda, BSAC ( UK), YMCA, BEES and LIFRAQ (Belgium ), NOB (Netherlands), DCIEM (Canada), DSAT (USA), PDIC, NRC, USC, SSI, etc.
- NOAA ( National Oceanic and Atmospheric Administration, U.S. Department of Commerce )
- Accident prevention regulations BGV C 23 (previously VGB39 ) ( 2002)
- RGBM ( Reduced Gradient Bubble Model ) by Dr. Bruce Wienke, 2002
Form and Structure
The deco tables themselves are in a different form: As a pure zero time tables, as tables for repetitive dives, as file, print in teaching tools, desktop application, web form, even as a mobile app slide rule. Not all tables are primarily intended for the actual dive, some serve only dive planning before diving. The ease of use and the risk of misinterpretation varies depending on the table differently. While some tables represent little more than no-stop dives, others include more sophisticated decompression dives or more Wiederholdungtauchgänge. ( multiple dives in one day ) decompression tables are used for the medical treatment of decompression chambers and for the planning of working time of overpressure workers in caissons. These usually other decompression models are used today but as the scuba diving.
Dekompressiometer
The Dekompressiometer is a viable method by pneumatic apparatus that was used before the advent of dive computers as a supplement to a table. He is a special form of a depth gauge, consisting of housing, water pressure membrane, ceramic membrane diffusion and the actual pressure measuring tube and indicator instrument. With the pointer tool compression and decompression is simulated physically. The result is displayed on a circular scale and gives the necessary decompression stops and times to.
Dive Computers
In contrast to today's tables are based on saturation dive computer simulations usually with more than one tissue type. Analog Tables Dive Computer with optimized modes for special breathing gas mixtures. Also, repetitive dives, JoJo dives or similar precisely recorded and calculated. A decompression table expects more conservative than a dive computer, which usually has more safety margin result in every case.
Security
A problem of all dive tables is that the adoption of a rectangular profile was applied. The diver must be read with the maximum depth and total dive time, the necessary decompression from the table. What may be suitable for professional divers proved for recreational divers who normally begin a slow climb after reaching the maximum depth, as too imprecise, because the resulting staircase profile can not be detected with a decompression table, however, are calculated by a dive computer more precise and less conservative.
For demanding decompression dives, it is recommended next to the dive computer a diver's watch, a depth gauge with maximum pointer function to display the maximum depth and to carry a pressure gauge and a water-resistant decompression table to the ( necessary for survival ) decompression meet in case of a malfunction of the dive computer when emerging to be able to. This redundancy benefits but little if the dipped before failure profile (immersion depth and bottom time ) was already close to the allowable limits, as no decompression table considered a real dive profile. Therefore, it is often recommended to carry redundant dive computer at risk dives ( for example deep, wreck, cave diving ).
Rules of Thumb
The various rules of thumb apply today, especially for the estimation of zero hours of rest before the flight in an aircraft (24 - hour rule ) or travel to higher locations. They provide reference values , which may be sufficient for simple dives well. Relevant formulas are about the calculation of the air is depleted for various depths. True security can not provide rules of thumb, however.