Technology
December 23rd, 2019
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Avalanche Airbag Inflation Systems – What’s the Difference? Compressed Gas vs Battery vs Supercapacitor

There are several different types of avalanche airbag inflation systems available on the market today from brands such as Highmark, PIEPS, Scott, Orotovox, Klim, BCA and Black Diamond.

But how do these avalanche airbag inflation systems differ, and what are some of the advantages of each? Those are the questions we aim to answer here!


How Avalanche Airbags Work

First we’ve got to understand the basics of how an avalanche airbag works—without going into too much detail. Basically, small objects in a moving avalanche will be filtered to the bottom of the moving debris while larger objects will be sifted to the surface. By increasing the volume of an object moving in a slide, an airbag can make a victim more likely to end up on the surface rather than buried beneath.

Inflated avalanche airbag

So it is size (volume) that we’re looking for. And how do you make a small, compact object much larger in size quickly? Inflate it!

Avalanche Airbag Inflation Systems – What’s the Difference?

So now that we know how airbags work, we have a better understanding of what is required to inflate the airbag and quickly increase the effective volume of the victim in an avalanche.

Let’s set aside the difference between using air and other gases for a moment, and take a look at the delivery method. All avalanche airbags either use a cylinder(s) of compressed gas, or an electronic fan-based inflation method. Let’s start with the compressed gas cylinder.

Compressed Gas Cylinder Airbag Inflation Systems

Currently, avalanche airbags that use compressed gas cylinders are more common than electronic, fan-based airbags. That technology has been in use longer, so it’s better established at this point.

These cylinders contain either compressed air (what we breathe) or some other type of gas.

Compressed Air Cylinder Inflation Systems

This is the most common type of avalanche airbag inflation system out there. The Snowpulse system—used by Highmark, Mammut and Dakine—uses regular ol’ air, as do the BCA and Ortovox systems.

When the airbag is deployed, the air is released from the compressed cylinder into the airbag through a venturi system that also pulls ambient air into the airbag to help it fill to specification.

In addition to the compressed air inside the cylinder, the venturi system pulls a significant volume of ambient air from either inside or outside the pack to help inflate the airbag.

These systems use a small, lightweight, refillable aluminum cylinder that is filled with air between 2500-3000 psi. This can be done at supporting retail shops and dealerships, or even at SCUBA shops or paintball venues.

Avalanche Airbag Inflation Systems-2
Highmark and BCA are two brands that use a compressed air inflation system.

To hold the air in the cylinder, the Highmark, Mammut, Dakine and Ortovox systems all use a thin, copper burst disk. When the airbag handle is pulled, a mechanical cable actuates a spike that penetrates through the thin layer of metal to release the air from the cylinder.

The BCA system is a little different. When the BCA airbag handle is pulled, a valve stem sealed by an O-ring slides up, releasing air into the system.

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Most compressed air cylinders use an easily punctured, thin metal disk to seal the compressed air inside.
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The BCA 2.0 systems relies on a small O-ring to control air pressure.

While these two systems are fundamentally the same, the difference lies in the way the air is sealed in the cylinder. The BCA system relies on a rubber O-ring which has the potential to degrade over time and slowly leak, while the copper burst disk used by the other companies is unlikely to degrade.

Regardless, all compressed gas systems have the potential to lose pressure over time, even if they rarely do in practice. For that reason, the cylinder pressure gauge should be checked prior to each ride, and any leaky cylinder be diagnosed and refilled.

Systems that Use Compressed Air

Highmark, BCA, Orotovox, Mammut and Dakine

Pros

  • Cylinders can be refilled by adept users with the right equipment
  • Filling with air is less costly than other gases
  • No reliance on electronic equipment
  • No maintenance required

Cons

  • Cylinders have the potential to lose pressure over time
  • Depending where you live, it might be difficult to locate a refilling station
  • There is a small refilling cost

Compressed Gas Cylinder Inflation Systems

These inflation systems are similar to those that use compressed air, but they use some other type of gas instead. In the case of the Alpride 2.0 system, it uses two small cylinders—one filled with argon and the other with C02. The ABS system uses a single larger cylinder filled with compressed nitrogen.

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The Alpride 2.0 system uses a twin pair of compressed gas cylinders, one filled with argon and the other with carbon dioxide.
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The Alpride cylinders are sealed from the factory and won't leak, however, when used they must be exchanged for two brand new cylinders.

The advantage to using other gases is that, unlike air, they do not support combustion, which is supposed to remove some restrictions on airline travel. However, when flying in the USA, users may still be required to notify their airline ahead of time and be subject to additional security hassles.

That aside, compressed gas inflation systems are also mechanical systems, which means they are maintenance free and not subject to any electronic requirements, such as charging and “powering on”.

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Systems That Use Compressed Gases

Scott, Klim, Black Diamond, ABS

Pros

  • Lighter than compressed air systems (Alpride only, ABS is heavier)
  • Sealed cylinders will not lose pressure (Alpride only, not ABS)
  • No reliance on electronic equipment
  • No maintenance required

Cons

  • Cylinders cannot be refilled, they must be exchanged
  • New cylinders (or exchanges) are expensive
  • Depending where you live, replacement cylinders might not be available
  • Cannot fly in USA with compressed gas cylinders (Alpride cylinders are IATA approved)

Electronic Airbag Inflation Systems

Currently there are two types of electronic airbag inflation systems, and the difference hinges on how they are powered. But these two types are similar in many ways, so let’s start there.

Electronic airbags must be charged and “switched on” prior to use. When the handle is pulled, a mechanical cable tells the electronic airbag to inflate. The power source provides energy to a high-speed fan, which pulls ambient air into the airbag.

One real concern with the electronic system is that the user might expose the deployment handle, but forget to “turn on” the airbag. In this case, the user would think they are protected by the airbag, but in fact it would not function when the handle is pulled. This can be mitigated with careful use. The other main drawback of the electronic system is the possibility that the user doesn’t check and recharge the system before riding.

The handle might be out, but it’s crucial that users also ensure that the electronic airbag is powered on, or else it won’t deploy when needed.

Otherwise, the electronic airbag has several advantages over a mechanical system. First of all, it is a no-cost deployment system, meaning you can practice with it or deploy it as often as you want without a cylinder refill or exchange cost. They can also be deployed more than once, which means if it is used in the field, the airbag can be repacked and ready for a second use if necessary.

Battery-Powered Fan Inflation Systems

The battery-powered inflation system was the first electronic airbag system on the market. However, the battery is considerably heavier than the supercapacitor-powered electronic system, and that is its main drawback.

Although lighter than the first generation, the battery is still a bit of brick.

However, there are a few advantages. Battery-powered avalanche airbag inflation systems can be continuously-filled, which means if the airbag is ripped or torn in the course of an avalanche involvement, the fan will attempt to maintain pressure in the airbag, which a supercapacitor or mechanical system cannot do.

A second advantage is that after three minutes, the battery-powered inflation system will run in reverse, which will quickly deflate the airbag. This can provide a buried victim a larger air pocket and allow easier extraction. Mechanical systems are designed to deflate as well, but it happens much more slowly.

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The fan operates at between 60,000 and 70,000 rpm, allowing a very fast inflation time. Ambient air is drawn from outside the airbag through the mesh.
Systems That Use a Battery

PIEPS, Black Diamond

Pros

  • Up to four deployments on a single charge
  • No refilling or cylinder exchange cost
  • No restrictions on flying
  • Airbag will be continuously filled for several minutes, which will help in the case of a ripped airbag
  • After three minutes, the fan will reverse and deflate the airbag creating an air pocket

Cons

  • Battery is Heavy
  • Expensive
  • Users must remember to charge the system between rides
  • There is potential for a user to have the handle out but not turned on, resulting in no deployment when needed

Supercapacitor-Powered Inflation Systems

Supercapacitor-powered avalanche airbag inflation systems are the latest in avalanche airbag technology.

The main benefit is that supercapacitors are lighter than a battery. Similar to the battery-powered airbags, a radial compressor is used to inflate the airbag quickly.

The supercapacitors recharge via USB. However, the airbag can also take two AA batteries which allow the supercapacitors to hold a charge longer and also will allow a second deployment in the field if necessary. Note that it takes the AA batteries an hour or so to recharge the supercapacitors after a use.

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The supercapacitor housing is smaller and lighter than the fan-based system.
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The supercapacitors can be charged via USB or two AA batteries.

Otherwise, the supercapacitor-based system is subject to much of the same advantages and drawbacks as its electronic sibling, the battery-powered system.

Systems That Use Supercapacitors

Scott, Klim, Black Diamond

Pros

  • Lighter than a battery powered system
  • Can be deployed a second time in the field (with a one hour recharge time)
  • Supercapacitors are not influence by cold temperatures
  • Two AA batteries will maintain the supercapacitors charge for 2-3 months until used
  • No restrictions on flying

Cons

  • Expensive
  • Users must ensure supercapacitors are charged before each ride
  • There is potential for a user to have the handle out but not turned on, resulting in no deployment when needed
  • Must remember to remove batteries for storage

Regardless of which type avalanche airbag inflation system you choose to use, there are several important things to remember!

PRACTICE deploying your airbag! Non-inflations is considered the greatest limitation to the effectiveness of airbags, and sixty percent of all non-inflations are due to deployment failures by the user.*

Always be sure to check your airbag prior to riding with it. That means check the pressure gauge if it’s a mechanical system, or the charge if it is electronic.

Expose the deployment handle BEFORE heading into avalanche terrain. If your airbag is electronic, be sure to turn it on at the same time.

 

 

And finally, don’t let the additional protection afforded by your airbag negatively affect your decision-making in avalanche terrain.

 

– PG

 

* (Haegeli, P., M. Falk, E. Procter, B. Zweifel, F. Jarry, S. Logan, K. Kronholm, M. Biskupic, and H. Brugger, 2014: The effectiveness of avalanche airbags. Resuscitation.)