Avalanche airbag
The avalanche airbag (avalanche airbag system, avalanche backpack) is a reusable rescue device that is supposed to increase the probability of survival of people who have been hit by an avalanche . The avalanche airbag is intended for ski tourers and alternative skiers who move away from the secured slopes .
history
The head forester Josef Hohenester from Bad Reichenhall made the experience in the 1970s that he was not buried by the snow masses in a slab avalanche , but stayed close to the surface when he was carrying game on his shoulders. He was able to reproduce this behavior through tests with large-volume canisters and balloons, which he observed in avalanches. A research center confirmed its theory through a series of professional tests. The registration of the patent ( Patent Application DE2326850A : . Device for displaying and self rescue his carrier in avalanches Me on May 25, 1973 , published on December 19, 1974 , Applicant: Joseph High nests, inventor Joseph High nests. ) By the forester, to Avoiding a total burial, increasing the total volume was the hour of birth of the avalanche airbag.
After Joseph High nests in 1980 the patent ( Patent DE2326850B2 : device for rescuing people in avalanches. Remember on May 25, 1973 , published on October 20, 1977 , Applicant: Joseph High nests: Joseph High nests, inventor. ) Had to Peter Aschauer sold In the same year he began to develop a system that would allow volume to be increased within a few seconds in an emergency and should not hinder snow sports enthusiasts. The first functional avalanche airbags were manufactured by ABS Peter Aschauer GmbH and were available in 1985. They were based on a large airbag with a volume of 150 liters placed centrally on the back.
In 1996, ABS Peter Aschauer GmbH switched to two side-mounted, movable airbags with a total volume of 170 liters. In addition, the cable release for inflating the airbags has been changed to a faster and considerably more reliable pyrotechnic-pneumatic release.
In 2016 ABS Peter Aschauer GmbH (since 2017: ABS Protection GmbH) developed the first avalanche airbag with integrated remote release. This enables the users of the avalanche backpack to release previously grouped backpacks using their own release handle. This means that the partner's avalanche backpack can also be triggered at a distance of approx. 300 m with the model called p.RIDE.
Structure and principle of operation
The avalanche airbag is integrated in a backpack. At ABS Protection GmbH, it consists of two signal-colored polyamide balloons that are folded up on the right and left side of the backpack. Other manufacturers only use a balloon. If the snow sports enthusiast is caught in an avalanche, they can inflate the two airbags by pulling a handle on the front of the backpack. With the help of a nitrogen cartridge with an internal pressure of approx. 300 bar, the airbags are inflated to a total volume of approx. 170 liters within 1–2 seconds.
The additional volume is intended to prevent the victim from being buried by the avalanche, because the risk of suffocation decreases on the snow surface. The victim can be found faster and can eventually free himself. If the victim stays on the surface of the snow, the mortality rate is between 3 and 4%, for completely buried people it is around 54%.
A fully equipped skier with an inflated avalanche airbag has an average density of approx. 400 kg / m³, while an average density of 300 kg / m³ is assumed for flowing avalanche snow. The fact that an avalanche victim with an inflated avalanche airbag tends to lie on the surface cannot be explained by hydrostatic buoyancy. The physical background for the floating is the Brazil nut effect . This leads to the fact that in a flowing medium like an avalanche, the larger bodies in terms of volume settle on the surface, while the smaller bodies sink to the bottom, as they can lie closer to one another and therefore occupy a comparatively very high overall density. This effect can also be observed in a bowl of muesli when it is shaken. The larger muesli components rise, the smaller muesli components fall. This is why this effect of bodies in moving media is colloquially called the muesli effect .
The system can be reused after the airbags have been folded up with a new deployment unit. The release units themselves are reused via a deposit system.
An avalanche airbag is only an extension, but not a replacement, of the standard equipment for ski tourers and alternative riders. It is essential to carry an avalanche transceiver , an avalanche shovel and an avalanche probe .
Avalanche airbags are offered by several manufacturers and weigh from 1.5 kg. Although they differ in terms of their technical implementation, they are all based on the “muesli effect”.
Functional & statistical studies by the SLF
Tests by the Swiss Federal Institute for Snow and Avalanche Research (SLF) in February and March 2001 were intended to clarify the effectiveness of avalanche rescue devices. In an extensive test on March 16, 2001, 3 out of 7 (approx. 42%) of the human-like dummies with avalanche airbags were completely buried with the help of artificially triggered avalanches. The 3 dummies were not visible on the surface. Their burial depth, however, was less than that of the totally buried dummies without an avalanche airbag. The airbags of all 7 dummies were visible on the snow surface and would have shortened the rescue time considerably in an emergency.
In comparison, 5 out of 6 dummies (approx. 83%) were completely buried without an avalanche airbag.
According to a statistical analysis of 86 documented avalanche accidents between 1991 and 2005 by the SLF, 95% of the people with an avalanche airbag survived the avalanche. Overall, it was found that the chance of survival for all persons who were not or only partially buried is at least 97%.
"Of the systems currently available, the avalanche airbag offers the greatest chance of surviving an avalanche accident."
See also
Web links
- Field tests with avalanche emergency devices winter 2010/11 , Lorenz Meier, Stephan Harvey, SLF.CH, PDF
- Avalanche airbag and avalanche ball tested , YouTube
- "Emergency equipment for ski tourers and alternative drivers " , critical analysis of avalanche airbags, Avagear, LVS, AvaLung & Avalanche Ball ( avalanche ball ), mountaineering, April 2003, PDF (159 kB)
Individual evidence
- ↑ a b c history of development
- ↑ Dr. med. Hermann Brugger, President of the International Commission for Alpine Emergency Medicine - ICAR MEDCOM .
- ↑ a b Avalanche accidents in the Swiss Alps ( memento of the original dated August 24, 2015 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. (PDF; 150 kB), static compilation with a focus on burial, rescue methods and rescue equipment, Frank Tschirky, Bernhard Brabec and Martin Kern, Federal Institute for Snow and Avalanche Research, 2001.
- ↑ Physics at breakfast (PDF; 3.2 MB), Volkhard Nordmeier, Hans J. Schlichting, 2008.
- ^ Avalanche airbags , G. Süsskraut, Deutscher Alpenverein , January 2013, PDF.
- ↑ a b Field tests on the effectiveness of some new avalanche rescue devices ( memento of the original from September 22, 2007 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. , Martin Kern, Frank Tschirky, Jürg Schweizer & Federal Institute for Snow and Avalanche Research (SLF), Innsbruck, 2001, PDF .
- ↑ Hans-Jürg Etter: Compilation of the research results on personal avalanche emergency equipment . In: Austrian Board of Trustees for Alpine Safety. 6th Alpinforum, "Emergency equipment - the latest craze" . 2008.
