English
Out of all the natural events we could have taken into consideration we chose one which is pretty frequent in our area,
We decided to investigate this fact and then try to design a system that improves the possibilities of survival for all those – daredevils and rescuers - who get buried by an avalanche.
There are various useful emergency supports already on the market. Some aim at a most rapid localization of the victim. Those are the systems Arva and Recco. Arva sends a signal which can be received by the same device. In fact when a member of the excursion team gets buried, the others can immediately put thier Arva device in receiving mode and start the search. Once the victim is found rescuers use a more precise little probe and then start to dig. In the meantime professional rescuers are called.
The Recco system instead does not use an electric device for the signal, but only a reflector incorporated in the sportswear. It is simpler and does not need batteries to function. People engaged in the search for buried victims need a particular receiver which can even capture the signal from a helicopter. The presence of water might result in a less efficient signal, though.
Both systems are crucial and allow immediate digging at the exact location. Unfortunately both systems still do face a serious problem: in case nobody was present at the moment of the avalanche and so nobody can launch alarm, the time of a possible recovery are too long for the victim to survive.
There are other systems to prevent damage caused by burial. In particular the free-rider, an often used device called A.BS. (Avalanche Airbag System), which consists in a back pack with two incorporated airbags, which enable to "float" on the avalanche and not to get buried below more than 20-30 cm of snow. Also the rescue teams are equipped with this system.
But this system is not very popular with winter sports fans because of its weight and volume. The rescue expert we contacted told us that its use is not very widespread and only who practices the disciplines at an extreme level actually uses it. The cost is not indifferent either and unfortunately people are often ready to spend a lot of money on sportswear and ski but tend to under estimate the importance of safety.
Another system is called Avalung. This system filters the air at the victim’s disposal by eliminating CO2 and such improving the remaining air. But it does not actually increase the air at disposal and if no air sac forma this device is useless. A further problem can arise is the difficulty to keep the mouthpiece stable during the dragging.
So we learnt that it is difficult to apply preventative measures. These sports are fascinating and induce to ignore the avalanche risk forecasts und the simplest safety rules.
Having taken all this into consideration we tried to create a light, handy and less expensive device. The idea was to provide oxygen to make sure that the victim can breath as long as the organism is able to resist the cold.
2. Problem analysis and problem solving
Avalanche events:
It has been a while that in
The possibility to be save is first of all linked to the chance of getting immediate rescue, which means the presence of some witness, hopefully in possession of Arva, who start the search even before the arrival of the helicopter.
If buried under an avalanche one’s survival is closely linked to three important factors: trauma suffered during dragging downhill, lack of oxygen during the first 15-35 minutes, hypothermia after this first stage.
During this phase it is crucial to have access to oxygen. A buried victim with obstructed breathing channels has only few minutes to survive and can only hope for the presence of people able to start digging immediately. If luckily an air sac is formed in front of the victim’s face it is possible to resist longer.
Our idea was to provide oxygen to extend the time one can resist and such living the rescue teams a better chance to successfully finish their search and digging.
We thought of a vest that incorporate san oxygen tank. This vest needs to have a couple of tiny airbags at shoulder height which fill to form head protection. Through the deflation of the airbags this system provides an air sac in front of the victim’s face. Without this precaution the oxygen could become completely useless. Once the avalanche came to a halt the flow of oxygen starts to extend the time of survival, we established a maximum of 60 minutes.
3. Obtained results and possible applications
Having decided on the object to be created we tried to verify the feasibility of our idea.
First we tried to under stand how much oxygen is needed to survive up to 60 minutes. Based on the established amount we projected the dimensions of the tank for oxygen under pressure.
It is difficult to determine the oxygen quantity precisely, because it depends on many factors (presence of effort at the moment of burial, lack of consciousness, age, physical condition). Rescue teams estimate an average value of 10 liters per minute. A 2-liter tank under 200 bar pressure can provide 400 liters of oxygen, consuming 10 liters per minute it would guarantee autonomy for 40 minutes.
Considering that under those conditions the vital functions are reduced and less oxygen is needed, this quantity of oxygen can surely be sufficient for another 10 minutes approximately. Research available reports that it is very difficult to estimate those values because of the high amount of variables that affect them, but it is quite sure that 60 minutes are possible.
The airbags are positioned on the front shoulders and inflating create two “columns” to protect the face, reducing the risk of cervical trauma which are very frequent in this kind of incident.
The back protection, apart from providing the system support, improves the overall protection.
The airbags, even thug nota s big as the ABS ones, can help the victim to “float” and avoid to be buried too deep under the snow. We plan to use two with a 30-liter volume each.
The oxygen tank and the one to inflate the airbags are located on the upper part of the back. The handle to open the CO2 flow which inflates the airbags we decided to apply on breast level. The system could be the same as used for the ABS device. After pulling the safety latch the airbags inflate. After another 2-3 minutes, the avalanche having stopped, the oxygen flow can start automatically.
We are currently investigating the possibility to get rid of the gas resulting from airbag deflation applying the same criteria proposed by Avalung. An alternative could be to use a different type of gas to inflate the airbags.
The advantages of our system are definitely its reduced costs and weight. It could also be suitable for rescue teams who need to use a lot of other equipment.
We also tried to estimate its weight. To do this we surfed the internet to look for data of similar products on the market for different use (airbags, gas tanks, back protections). Weight should not exceed 2-2,5 kg.
Our system is called Avalanche Survival Air System and this is its logo:
