Decompression Sickness Risk
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Prior to using this free decompression software, it is a good idea to read the
Instruction Guide and Manual.
This page is very important to read.
Divers are taught that there is always a risk of decompression
sickness after any dive and that no dive table, computer, or software
program can guarantee that decompression sickness will not occur.
This needs to be taken very seriously. In addition to reading and
articles on this web site including
decompression strategies and
ascending from a dive, a
diver needs to plan their dives conservatively.
Many dives that are acceptable according to tables have resulted in
decompression sickness. The following are some examples from some
controlled studies. Therefore, plan your dive very conservatively
especially since decompression divers are choosing to enter into
mandatory decompression obligation.
Recreational Dive Tests on air (descent and ascent rate was 30 feet (9 m.)
100 feet (30 meters) for 20 minutes: 2.7% decompression
40 feet (12 meters) for 60 minutes followed by a 60
minute surface interval and then another dive to 40 feet (12 meters) for
60 minutes resulted in a 2.5% decompression sickness incidence.
This is after a surface interval between the dives where the diver is
off-gassing even though most tables and software would allow this dive
to 40 feet/12 meters for 120 minutes straight without the surface
interval which would result in a higher decompression incidence.
Decompression Dive Tests (on air) by the U.S. Navy Experimental
170 feet (52 meters) for 30 minutes followed by 174 minutes
of decompression with a very acceptable profile resulted in a
1.5% decompression sickness incidence. This is generally considered an
acceptable limit with testing unless you are the diver that got
decompression sickness without being next to a recompression chamber.
For comparison purposes, the DCIEM tables only require 77
minutes of decompression, IANTD's tables only require 67 minutes of
decompression, Buhlmann only requires 66 minutes of decompression (30
minutes at 51 meters/167 feet), and original RGBM tables only required 22 minutes of
decompression (for 170'/25 minutes - a 30 minute profile was not
published) - all of which would increase the decompression
sickness incidence dramatically. While Departure's software in a
nominal opened up mode would require 104 minutes of decompression and in
slightly mild setting would require 165 minutes of decompression (with
more adjustment possible based on the settings chosen), this
still shows that some incidence of decompression sickness would occur in
There are many more examples, so again, dive smart and