Why this Organization ?
IDREO is a NON profit organization founded for increasing
safety in overhead environment Research and Exploration
worldwide.
Exploration is not longer a exclusive group activity, new
technology allow divers to perform exploration activities as
early days exploration are perform in a daily basis, and divers
are reaching further than ever before.
Information however is not accessible to most and therefore
we have diver fatalities, an increase actually, as much as two
times the numbers in comparison 2011 to 2010 (only in cave
diving alone), mostly under exploration.
Research is been enhanced by the new equipment develop for
exploration, “reaching further”, so are quickly becoming the
working tools for researchers worldwide.
Besides needing to master the equipment operation and
procedures, so they can resume research and experimentation
in newly reach areas, researcher activities such as sampling,
documentation and data collection under standardization will
create a more uniform platform for international research.
Mission
Create awareness of Exploration risk, and
provide up to the minute knowledge to
current and new generation of explorers
thru an International platform.
Articles related to latest Accident Analisis.
2011
Making a successful switch of Gas
by Nick Toussaint 01/2012
In 2011 all rb divers fatalities in cave accidents, were due to a
wrong gas choice or weak procedure when switching breathing
mix.
In this article I will suggest techniques and procedures that I
have been applying successfully in the last 17 years of
exploration and research projects worldwide at extreme
depths and dive times, with zero incidents or accidents.
The first key thing to do is to invest in owning a specific bottle
to each mix used, changing mixes in same bottle is proof to be
the biggest error.
The important issue is breathing a gas beyond is acceptable
range, with maximum operating depth (MOD) been the easiest
way to monitor mix high PO2, specially if not being analyzed
through the dive.
MOD is related to gas function with a PO2 of 1.6 as overall
maximum, however only applied in decompression from
36mt/120ft stops, deep deco (+36mt/120ft) max are kept to
PO2 1.4 as the risk is to high for the PO2 benefit, bottom gas
PO2 to less than 1.2 and in extreme dives keep it under PO2
0.7 to keep CNS to 0%
The PO2 choice for the bottom is independently separate than
the gas actual MOD, you do not have to use the gas always to
its MOD, simply make sure to stay above it's MOD.
MOD is then pretty standard and written clearly and
permanently on ALL bottles, deco and bottom mixes.
Second point is the need to analyze the gas with at least one
O2 sensor, while helium is nice to check is more important CO
check.
Analyzing is key as MOD do not tell you what gas you have in
the bottle only suggest to what depth is usable. In example
21mt/70ft bottle can be three mixes 50% O2, 50/25 or heliox
50/50. As O2 content is the same MOD remains the same
21mt / 70ft
While mistakes under mixing are possible, avoiding filling a mix
which is not possible to be breath at bottle MOD is by far the
best conduct. Even if it means to dump the gas out of bottle.
MOD and gas analysis however is not enough to ensure proper
gas switches, as the switches are done in the water, this is by
far the most important moment in the dive and we should stop
and give it the full attention it deserves.
Switching to a bottle takes about one minute per diver, so
even in large teams it will take around 2-3 minutes. No need to
rush it.
I take advantage of my dive partners and ask them to stop
whatever they are doing and verify my gas switch.
I show the bottle I am willing to switch to and make sure it's
MOD is clearly visible, confirming is the right bottle by cross
checking depth gauge and team acceptance I finally switch.
Step by step will be : Stop and get your team attention, if they
are busy wait, when you get full attention give the signal of
switch gas, team will stop doing anything else than verifying
your switch, while at the same time team is supposed to be
also keeping reference and monitoring depth changes.
Partner will not switch and will wait for its turn, so we switch
one at the time. If in a team of three one diver needs to watch
while the others switch. Here the "watching diver" stays in
travel direction position while switching divers are perpendicular
to line.
Is obvious that there is the possibility that something goes
wrong at regulator switching either failure or even a mistake,
“watch divers” must be ready to stop and even share gas, but
most likely is to be momentarily, until diver find a next gas
source.
The Switching procedure that has best work for us is that
while leaving attach by bolt snap the neck of bottle , detach
bottom bottle bolt snap from harness D ring and swing it in
front of you, check your MOD and check with your depth
gauge and team.
If all is OK, then detach second stage and keep it in your right
hand, while with left hand attach bottle back to harness. Slide
left hand down the bolt snap through the bottle to its valve
and open it, purge stage reg with your right hand and place it
in your mouth simultaneously with left hand removing former
reg. ( before storing previous regulator verify new regulator is
working properly )
The above procedure is definitely safer than everybody in the
team doing their switches at the same time without any
supervision. Which again, is the main cause of cave fatalities in
2011.
Several teams with even cave instructors and even pSCR
rebreather instructors, some from the top training agencies,
have failed to recognized buddy wrong gas switches and even
wrong gas “drop” placements.
Proper bottle placement is obviously important as to have the
right gas at the right place, however miss placing a bottle
should be quickly identified with switching procedure explained
above.
As a rule a Mix should not be taken deeper than their MOD.
Sometimes is not possible as in multiple deep sump diving, etc.
To drop properly bottles spread task in the team, assign one
gas drop per diver, as in one diver drops ALL team O2 bottles,
while team supervise. Next diver in team will drop the
21mt/70ft bottles and so on.
This technique greatly reduces mistakes due to over task
loading, as then each diver drops one time instead of three
times, receives supervision at drop and also team creates less
impact on visibility and promotes cave conservation.
When doing solo switches, even while diving with others but
not as a team, the risk is higher as there is no supervision.
Adding a PO2 gauge to rb will greatly increase chances of
identifying a wrong gas switch, while in OC is not an option.
In all diving breathing Mixes besides MOD there is a MinOD
directly proportional to O2 in mix, in example on Hipoxic Trim
ix 10/70 MinOD is 6mt/20ft or PO2 0.16.
With rb this issue increases as O2 content is dropping in every
breath. So even in OC Nitrox 32% can be breath in the surface
so MinOD is the surface, in a pSCR rebreather Nitrox 32%
MinOD is from 6-9mt /20-30ft depending on diver/rb efficiency.
Last using the same mixes repeatedly will allow you to
familiarize with the dropping areas and switches depths. Let
alone predict decompression more efficiently.
If you have any comments or questions contact me at
info@nick-toussaint.com
safety in overhead environment Research and Exploration
worldwide.
Exploration is not longer a exclusive group activity, new
technology allow divers to perform exploration activities as
early days exploration are perform in a daily basis, and divers
are reaching further than ever before.
Information however is not accessible to most and therefore
we have diver fatalities, an increase actually, as much as two
times the numbers in comparison 2011 to 2010 (only in cave
diving alone), mostly under exploration.
Research is been enhanced by the new equipment develop for
exploration, “reaching further”, so are quickly becoming the
working tools for researchers worldwide.
Besides needing to master the equipment operation and
procedures, so they can resume research and experimentation
in newly reach areas, researcher activities such as sampling,
documentation and data collection under standardization will
create a more uniform platform for international research.
Mission
Create awareness of Exploration risk, and
provide up to the minute knowledge to
current and new generation of explorers
thru an International platform.
Articles related to latest Accident Analisis.
2011
Making a successful switch of Gas
by Nick Toussaint 01/2012
In 2011 all rb divers fatalities in cave accidents, were due to a
wrong gas choice or weak procedure when switching breathing
mix.
In this article I will suggest techniques and procedures that I
have been applying successfully in the last 17 years of
exploration and research projects worldwide at extreme
depths and dive times, with zero incidents or accidents.
The first key thing to do is to invest in owning a specific bottle
to each mix used, changing mixes in same bottle is proof to be
the biggest error.
The important issue is breathing a gas beyond is acceptable
range, with maximum operating depth (MOD) been the easiest
way to monitor mix high PO2, specially if not being analyzed
through the dive.
MOD is related to gas function with a PO2 of 1.6 as overall
maximum, however only applied in decompression from
36mt/120ft stops, deep deco (+36mt/120ft) max are kept to
PO2 1.4 as the risk is to high for the PO2 benefit, bottom gas
PO2 to less than 1.2 and in extreme dives keep it under PO2
0.7 to keep CNS to 0%
The PO2 choice for the bottom is independently separate than
the gas actual MOD, you do not have to use the gas always to
its MOD, simply make sure to stay above it's MOD.
MOD is then pretty standard and written clearly and
permanently on ALL bottles, deco and bottom mixes.
Second point is the need to analyze the gas with at least one
O2 sensor, while helium is nice to check is more important CO
check.
Analyzing is key as MOD do not tell you what gas you have in
the bottle only suggest to what depth is usable. In example
21mt/70ft bottle can be three mixes 50% O2, 50/25 or heliox
50/50. As O2 content is the same MOD remains the same
21mt / 70ft
While mistakes under mixing are possible, avoiding filling a mix
which is not possible to be breath at bottle MOD is by far the
best conduct. Even if it means to dump the gas out of bottle.
MOD and gas analysis however is not enough to ensure proper
gas switches, as the switches are done in the water, this is by
far the most important moment in the dive and we should stop
and give it the full attention it deserves.
Switching to a bottle takes about one minute per diver, so
even in large teams it will take around 2-3 minutes. No need to
rush it.
I take advantage of my dive partners and ask them to stop
whatever they are doing and verify my gas switch.
I show the bottle I am willing to switch to and make sure it's
MOD is clearly visible, confirming is the right bottle by cross
checking depth gauge and team acceptance I finally switch.
Step by step will be : Stop and get your team attention, if they
are busy wait, when you get full attention give the signal of
switch gas, team will stop doing anything else than verifying
your switch, while at the same time team is supposed to be
also keeping reference and monitoring depth changes.
Partner will not switch and will wait for its turn, so we switch
one at the time. If in a team of three one diver needs to watch
while the others switch. Here the "watching diver" stays in
travel direction position while switching divers are perpendicular
to line.
Is obvious that there is the possibility that something goes
wrong at regulator switching either failure or even a mistake,
“watch divers” must be ready to stop and even share gas, but
most likely is to be momentarily, until diver find a next gas
source.
The Switching procedure that has best work for us is that
while leaving attach by bolt snap the neck of bottle , detach
bottom bottle bolt snap from harness D ring and swing it in
front of you, check your MOD and check with your depth
gauge and team.
If all is OK, then detach second stage and keep it in your right
hand, while with left hand attach bottle back to harness. Slide
left hand down the bolt snap through the bottle to its valve
and open it, purge stage reg with your right hand and place it
in your mouth simultaneously with left hand removing former
reg. ( before storing previous regulator verify new regulator is
working properly )
The above procedure is definitely safer than everybody in the
team doing their switches at the same time without any
supervision. Which again, is the main cause of cave fatalities in
2011.
Several teams with even cave instructors and even pSCR
rebreather instructors, some from the top training agencies,
have failed to recognized buddy wrong gas switches and even
wrong gas “drop” placements.
Proper bottle placement is obviously important as to have the
right gas at the right place, however miss placing a bottle
should be quickly identified with switching procedure explained
above.
As a rule a Mix should not be taken deeper than their MOD.
Sometimes is not possible as in multiple deep sump diving, etc.
To drop properly bottles spread task in the team, assign one
gas drop per diver, as in one diver drops ALL team O2 bottles,
while team supervise. Next diver in team will drop the
21mt/70ft bottles and so on.
This technique greatly reduces mistakes due to over task
loading, as then each diver drops one time instead of three
times, receives supervision at drop and also team creates less
impact on visibility and promotes cave conservation.
When doing solo switches, even while diving with others but
not as a team, the risk is higher as there is no supervision.
Adding a PO2 gauge to rb will greatly increase chances of
identifying a wrong gas switch, while in OC is not an option.
In all diving breathing Mixes besides MOD there is a MinOD
directly proportional to O2 in mix, in example on Hipoxic Trim
ix 10/70 MinOD is 6mt/20ft or PO2 0.16.
With rb this issue increases as O2 content is dropping in every
breath. So even in OC Nitrox 32% can be breath in the surface
so MinOD is the surface, in a pSCR rebreather Nitrox 32%
MinOD is from 6-9mt /20-30ft depending on diver/rb efficiency.
Last using the same mixes repeatedly will allow you to
familiarize with the dropping areas and switches depths. Let
alone predict decompression more efficiently.
If you have any comments or questions contact me at
info@nick-toussaint.com
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