Sep 25 2017

Arva Reactor 32/40 liter airbag packs

Arva's Reactor 32 airbag pack

Arva’s Reactor 32 airbag pack

Arva has done a good job of balancing opposing goals with their Reactor avalanche safety packs. They provide ample touring utility while minimizing the weight of the airbag plumbing. The ingredients are a text book example of how to synthesize the best features currently available for cartridge systems:

  • inert gas,
  • a mechanical trigger for simplicity
  • dual airbags extending the length of your torso
  • It was an easy decision for Arva to stick with cartridges; besides having years of experience working with ABS as their pack manufacturer, electrically powered airbags don’t really have a long track record to prove their reliability.

    The Plumbing

    A smaller canister and dual port venturi valve rest in the center of the main compartment with a mesh cover and two conjoined airbags that wrap around the sides.

    Smaller canister and dual port venturi valve rest in the center of the main compartment with a mesh cover and two conjoined airbags that wrap around the sides.

    The Canister

    Smaller and lighter.

    Smaller and lighter.

    Arva didn’t just stick with the known performance of a compressed gas system, the foundation of airbag survival stats, they refined it. Canisters are filled with compressed Nitrogen (USA) or Argon (Europe). Both are an inert gas, to reduce potential icing at the venturi valve. You might not notice the inert gas, or the fact that it is higher pressure than similar, larger canisters from ABS, but you will notice the smaller size and lighter weight. In Europe you can even get a carbon cartridge, saving another half-plus pound (275 g) if you’re willing to pay more for less. The overall impact results in the 40 liter version weighing closer to six than seven pounds (6lbs., 1 oz. = 4 lbs., 12 oz. pack + 1 lb. 5 oz. US steel cartridge). With an EU cartridge, or a smaller pack, the system weighs even less.

    Mechanical, piercing trigger.

    Mechanical, piercing trigger.

    These pressurized cartridges use a cap that is mechanically pierced like the Snowpulse system so you don’t need to worry about feeding big brother a chill pill when you fly because they have a fit over your pyrotechnic “safety” equipment. The sealed cap means you can’t refill the cartridges, but Arva dealers will exchange your empty with a refill for $40 (circa 2017). If you’re traveling and can’t find an Arva dealer to rent or replace a cartridge with you could use an ABS cartridge since the head shares the same threads and seal. However, be aware these substitute cartridges are lower pressure so they are categorically less reliable since the Reactor venturi valve is designed for higher pressure.

    Mechanical Trigger

    Easy to grasp, fold away handle

    Easy to grasp, fold away handle

    Besides its mechanical simplicity, another advantage of a piercing trigger is the ability to practice and experience the pull tension without the cartridge connected. Once you’ve yanked on the handle and released it, the pin and spring driving it need to be retracted using a threaded plunger that you screw into the cartridge connection. It’s not quite the same as practicing by inflating, but it won’t cost $40 per pull either and it does build familiarity with where the handle is and how hard to pull.

    Southpaws will be relieved to know the trigger handle can be routed to either side of the pack. To prevent it being pulled accidentally the arms of the handle close up around a bushing that prevents being pulled. When covered with a neoprene “condom” it keeps the handle arms closed and is more likely to deflect than be snagged by a malicious branch. Just don’t forget to uncap and deploy the handle before you need it. Once open, it spins to accommodate any hand position.

    Conjoined Airbag

    Not all airbags are equal and there is more to the performance of an airbag than volume. Arva uses two balloons that are joined by a common wall at the top for a total volume of 150 liters. These conjoined bags are shaped to extend to the bottom of the pack when inflated potentially keeping your head higher because the “flotation” effect is enhanced based on increased surface area, not just volume. With separate chambers the value of the airbag is only halved if one side is punctured, not completely nullified. In addition, the venturi valve is split, providing separate intake ports to two distinct pipes feeding air and gas to the balloons.

    If you want two different sized packs, the airbag system can be transferred from one Reactor pack to another. It only takes about ten minutes, so double that your first time since you may want to read the manual first so you disconnect and reconnect everything in the right order.


    Reactor 32. Big enough for a day trip, or an overnight hut trip.

    Reactor 32. Big enough for a day trip, or an overnight hut trip.

    In terms of pack utility the usual compromises must be made. It’s a basic panel loader with the cartridge and plumbing in the middle of the main compartment, but it is covered well so you don’t ever snag something on it that you’re trying to scrunch inside or pull out. The other reason the main compartment remains usable is how the airbags are stuffed around the perimeter of the bag, not concentrated at the top of the pack. This also helps to distribute the weight of the airbag system more evenly.

    Because the airbag expands out the top and sides you can forget lashing skis to your pack A-frame style, no matter what size Reactor you get. Instead, there are webbing loops at the bottom for a diagonal carry, with a couple of places to secure the top corner on either side.

    Their are four sized packs, each with a slightly different configuration. The 32 liter version is a full panel loader. On top of the main compartment is a zipper accessed mid-sized panel with dual sliders. This utility compartment is large enough for stashing a shovel (blade and shaft disconnected), probe, skins, and a spare layer or snacks. It would be easy to access if it weren’t for the straps that, although useful for lashing a snowboard to the front, tend to just get in the way every time you want to get inside this outer panel. Annoying but typical of the compromises airbags impose on ski packs. Then there are two smaller pockets, one on top and the other over the utility compartment. The zipper length on both need work. The top pocket is a good size, holding lots of do-dads, but opens so wide that those small items regularly fall out. The front deep pocket is almost big enough to stuff a pair of skins into, except the zipper only goes halfway, from the bottom. It would be easier to access if it went full length.

    The 40 liter version has a top lid for accessing the main compartment, while smaller versions are panel loaders like the 32, but without the weird front pocket with the half zipped access.

    Mountaineering functionality is provided via ladder chains on either side and adjustable loops at the bottom for skis or other tools. When not in use, these can tuck inside a flap at the bottom of each ladder chain. Same for the lone leg loop that can be stuffed away when not in use.

    The suspension system is Spartan, but carries well. The padding on the back, hips and shoulders are minimal compared to large trekking packs, but adequate for a typical day tour. One final note, the metal belt buckle is easier to operate than typical plastic keyed buckles, and won’t break. It also makes it easier to slip the lone leg loop onto the waist belt.

    Bottom line

    This is an airbag pack that carries well, has an airbag system with nearly all the best features of ABS without an explosive trigger so you can fly through the tyrannical states of America without being hassled, and is above all, reasonably priced.

    Reactor Airbag Packs

    Model Volume Weight MSRP
    Reactor 18 L 4.4 lb. • 2.1 kg $600+
    Reactor 24 L 4.4 lb. • 2.1 kg $650+
    Reactor 32 L 4.4 lb. • 2.1 kg $700+
    Reactor 40 L 4.4 lb. • 2.1 kg $725+

    Reactor Cartridges (the plus on the price)

    Canister Volume Weight Gas Pressure MSRP
    EU Steel 200 ml. 450 g • 1 lb. Argon 300 bar • 4351 psi €90
    EU Carbon 250 ml. 310 g • 11 oz. Nitrogen 4351 psi €180
    US Steel 250 ml. 585 g • 20½ oz. Nitrogen 4351 psi $135

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