Suunto EON - Bühlmann 16 GF Algorithm

Wienke. (Suunto dive algorithms are a culmination of expertise and knowledge accumulated
over decades of development, testing and thousands upon thousands of dives.)
In Suunto Fused™ RGBM 2 the tissue half-times are derived from Wienke’s Full RGBM where
human body is modeled by fifteen dierent tissue groups. Full RGBM can utilize these
additional tissues and model the on-gassing and o-gassing more accurately. The amounts of
nitrogen and helium on-gassing and o-gassing in the tissues are calculated independently
from each other.
Suunto Fused™ RGBM 2 algorithm supports open-circuit and closed-circuit diving up to a
depth of 150 meters. Compared to previous algorithms, Suunto Fused™ RGBM 2 is less
conservative on deep air dives, allowing shorter ascent times during decompression dives. In
addition, the algorithm no longer requires tissues to be completely free of residual gases
when calculating no-fly times, thereby reducing the required time between your last dive and
flying.
The advantage of Suunto Fused™ RGBM 2 is additional safety through its ability to adapt to a
wide variety of situations. For recreational divers it may oer slightly longer no- deco times,
depending on the chosen personal setting. For open-circuit technical divers it allows use of
gas mixes with helium - on deeper and longer dives helium based gas mixes provide shorter
ascent times. And
finally, for rebreather divers the Suunto Fused™ RGBM 2 algorithm gives the
perfect tool to be used as a non-monitoring, set point dive computer.
NOTE: Suunto EON Steel devices with software version earlier than 2.0 use Suunto
Fused™ RGBM algorithm. Once updated to the latest software, Suunto Fused™ RGBM 2 will be
installed to the dive computer.
4.10.2. Bühlmann 16 GF algorithm
The Bühlmann decompression algorithm was developed by Swiss physician Dr. Albert A.
Bühlmann, who researched into decompression theory starting from 1959. The Bühlmann
decompression algorithm is a theoretical mathematical model describing the way in which
inert gases enter and leave the human body as the ambient pressure changes. Several
versions of the Bühlmann algorithm have been developed over the years and adopted by
many dive computer manufacturers. Suunto’s Bühlmann 16 GF dive algorithm is based on the
model ZHL-16C. This model has 16
dierent theoretical tissue groups with half times from 4
minutes up to 635 minutes.
4.10.2.1. Gradient factors
Gradient Factor (GF) is a parameter which is used only with the Bühlmann dive algorithm. GFs
are a way to add conservatism to the Bühlmann algorithm by adding deepstops to the dive.
GFs are divided into two separate parameters, Gradient Factor Low and Gradient Factor High.
By using GF with the Bühlmann algorithm you can set your safety margin for the dive by
adding conservatism to control when dierent tissue compartments reach their acceptable
M‑value.
Gradient factors are always
defined as percentages. The Low % value determines the first
deepstop, while the High % value defines the allowed M-value once surfacing. Using this
method, the GF changes throughout the ascent.
A commonly used combination is GF Low 30% and GF High 70%. (Also written as GF 30/70.)
This setting means that the first stop would take place once the leading tissue reaches 30% of
its M-value. The lower the first number is, the less supersaturation is allowed. As a result, the
first stop is required when you are deeper. In the following illustration, GF Low is set to 30%
Suunto EON Steel Black
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