Transcript Folie 1 - uni

Danger of icing of the scuba
regulator
– a neglected risk while diving
in mountain lakes
Daniel Hothorn (sport student) and
Hans-Volkhart Ulmer (Physiologist)
Institute of sports science, Johannes Gutenberg-Universität, Mainz,
Germany, [email protected]
4th international Symposium: “High altitude influence on human
performance: science and praxis” – Bohinjska Bela (Slovenia)
Sept. 8-13, 2009
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HOTHORN & ULMER: Risk of icing scuba regulator, 4th Symposium: Altitude & praxis
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Introduction, aim, methods, results, discussion, final conclusions
Diving in mountain lakes is very attractive.
Some special risks are described in
literature, however:
Especially the problem of decompression
during ascent of divers under changed
pressure conditions as consequence of the
lower ambient pressure in hight,
relevant for diving in mountain lakes > 300 m
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Introduction, aim, methods, results, discussion, final conclusions
An other problem is described rarely:
The icing of the scuba regulator by
water temperatures < 10 °C.
The scuba regulator reduces the
pressure of the air bottles from 200
bar in two steps until actual ambient
pressure for respiration under water
Technical instructions: e.g. http://www.divers-travelguide.com/fileadmin/bilder/pdf/HandbuchSL21.pdf
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HOTHORN & ULMER: Risk of icing scuba regulator, 4th Symposium: Altitude & praxis
Introduction, aim, methods, results, discussion, final conclusions
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HOTHORN & ULMER: Risk of icing scuba regulator, 4th Symposium: Altitude & praxis
Introduction, aim, methods, results, discussion, final conclusions
Icing of the scuba regulator
caused by
- lower water temperatures (permanent
temperatures of 4 - 10 C° in depths
> 20 m)
- the Joule-Thomson-effect
(decompression of gases in a pressure
reducer effects cold)
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HOTHORN & ULMER: Risk of icing scuba regulator, 4th Symposium: Altitude & praxis
Introduction, aim, methods, results, discussion, final conclusions
Diving in mountain lakes is only marginally
included in the basic courses of the great
diving associations PADI and SSI,
and only referring to the modified decompression conditions during ascent.
A similar situation was found in nearly all
other special courses for diving in mountain
lakes.
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Introduction, aim, methods, results, discussion, final conclusions
Prevention against fatal accidents by icing:
Complete redundant system of scuba regulators
and
knowledge, how to switch it in case of icing of the
primary system, also in darkness
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HOTHORN & ULMER: Risk of icing scuba regulator, 4th Symposium: Altitude & praxis
Introduction, aim, methods, results, discussion, final conclusions
Diving equipment with
two bottles for compressed air and redundant scuba regulators
ANLINKER, U. & CISCATO,
W.: TDI Trimix.
1. Auflage, TDI Germany,
2007, Jüchen www.tdisdi.de
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Introduction, aim, methods, results, discussion, final conclusions
Switching on the 2nd scuba regulator without look contact (REINTS, 2009)
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Introduction, aim, methods, results, discussion, final conclusions
By literature and own experience it seemed
for us that the danger of icing of the scuba
regulator and the necessity of a redundant
scuba regulator is not sufficiently known
among divers
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HOTHORN & ULMER: Risk of icing scuba regulator, 4th Symposium: Altitude & praxis
Introduction, aim, methods, results, discussion, final conclusions
Aim
– Evaluate knowledge about the icing
problem
– Evaluate use of correct equipment against
scuba regulator icing
– Evaluate the risk of accidents by icing of
scuba the regulator
In context with divers at a typical mountain
lake (Walchensee, Germany, 802 m)
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Introduction, aim, methods, results, discussion, final conclusions
Methods
–
Inquiry with a special manual of 30
divers at the Walchensee (802 m)
–
Interview with 3 regional therapeutic
recompression centres
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Introduction, aim, methods, results, discussion, final conclusions
Results
Inquiry of the divers:
- Most of them knew the necessity of special
decompression procedures
- but only half of them knew the danger of icing
of the scuba regulator and used, in consequence,
a complete redundant regulator system
- Only a minority had passed a special course for
diving in mountain lakes
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Introduction, aim, methods, results, discussion, final conclusions
Interview with decompression centres:
Nearly all serious accidents of divers
in mountain lakes were caused by
iced scuba regulators
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HOTHORN & ULMER: Risk of icing scuba regulator, 4th Symposium: Altitude & praxis
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Discussion
This study underlines the often neglected
importance of icing of scuba regulators during
diving in mountain lakes (definition > 300 m).
- Neglected in the curricula of basic courses
- Neglected by divers to join special courses for
diving in mountain lakes
- Neglected by divers to use redundant regulator
systems and to train how to use in case of icing
under realistic conditions
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HOTHORN & ULMER: Risk of icing scuba regulator, 4th Symposium: Altitude & praxis
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Final conclusion
- In every basic course for divers the risk of icing
of the scuba regulator should be underlined,
combined with the necessity to join special
courses for diving in mountain lakes.
- In these special courses the necessity to use
redundant regulator systems should be
explained and it should be trained during diving
in darkness, how to use them in the case of
icing of the primary system.
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HOTHORN & ULMER: Risk of icing scuba regulator, 4th Symposium: Altitude & praxis
Introduction, aim, methods, results, discussion, final conclusions
Thanks for Copyrights:
Wilk reints (sheet 9) www.dir-m.com"
H. Dederichs (sheet 8) www.tdisdi.de
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HOTHORN & ULMER: Risk of icing scuba regulator, 4th Symposium: Altitude & praxis
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The end
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HOTHORN & ULMER: Risk of icing scuba regulator, 4th Symposium: Altitude & praxis