Better Alternatives

Our test shows alternate inflation regulators can deliver big air when the pressure is on.

WHEN IT COMES to alternate air sources, it's hard to beat the streamlined functionality of an alternate inflation regulator. These fully functional regulators connect to, or are integrated into, your BC's power inflator, eliminating the traditional octopus hose and putting your backup reg close to your mouth and within easy reach.

It's not easy to build an inflator/reg because you have to cram a lot into a small housing - an ergonomically correct mechanism for inflating and deflating the BC, coupled with a reliable regulator that delivers a low work of breathing. But today's inflator/regs are relatively inexpensive, easy to install (although most manufacturers recommend your dive store do the installing), and most provide surprisingly easy breathing, as good as or even better than traditional octopus regs. They are designed to be connected to any first stage as long as the first stage's intermediate pressure falls within the inflator/reg's operational parameters (more on that later), which virtually all first stages do.

Bottom line: Inflator/regs are proven technology. Most models on the market perform we'll, but as we discovered in our test of eight of recreational diving's most popular inflator/regs, the newest designs have raised the bar in breathing performance and ergonomic design.

PUTTING THEM THROUGH THEIR PACES

OUR FIRST STOP was the Dive Lab, an independent test facility in Panama City Beach, Fla., where we do all of our breathing machine testing. Here the units were hooked up to an ANSTI breathing simulator and tested at two depths; 132 feet salt water (fsw), recognized as the maximum recommended depth limit for recreational scuba diving, and 165 fsw, the test depth used in the European testing standard EN250. At those two depths, the inflator/regs were subjected to two breathing rates or respiratory minute volumes (RMVs): 37.5 RMV, considered a moderately aggressive breathing rate, and 62.5 RMV, a heavy-work breathing rate, both of which can be used to simulate a nervous, stressed or panicked diver.

To make sure we were focusing on the performance of the inflator/regs rather than on another component in the system, we used the same regulator first stage for all tests. Its intermediate pressure was set at 136 psi, which not only falls right in the middle of most manufacturers' recommendations, but also represents the mid-range pressure setting of most first stage regulators. The supply pressure to the first stage was maintained at 725 to 765 psi, which is the standard pressure range used for European testing and past ScubaLab tests.

The breathing machine measures work of breathing, or how much effort a diver has to put into inhaling and exhaling, expressed in joules per liter 0/1). The lower the number, the easier the breathing. European standards set the maximum breathing effort at 3 j/l, which is also what we use in our tests. We started each inflator/reg at the surface breathing at 62.5 RMV, then slowly took it to 132 feet. If the unit could handle that depth within the 3 j/l standard, we took it down to 165 feet. if the regulator couldn't make it to 132 feet, the max imum depth achieved was recorded and the cycle was completed at the lower breathing rate of 37.5 RMV (see chart, pg. 101).

When a regulator exceeds 3 j/l, it "fails" our test for the given RMV/depth. That doesn't mean that it stops working, just that the effort it required exceeds what has become acceptable for modern recreational gear.

Once the simulator tests were done, our test divers took them on repeated ocean dives. Each unit was scored on four crucial ergonomic points: ease of breathing in various positions, whether it breathed wet or dry, how easy it was to purge the inflator/reg, and how easy the controls---inflator button, deflator button and regulator purge-were to find and use, both when using the unit as a BC inflator, and when using it as a regulator.

THE TESTERS' CHOICES

Atomic Aquatics SS1

This new inflator/reg offers performance to spare in a userfriendly package. The SS1 breathes better than many primary-use regulators and generated the best overall simulator performance among the integrated inflator/regs (only the Gemini, which does not incorporate an inflator into its design, could beat it), then hit the water and earned the highest ergonomic scores of all the units we tested.

A low profile enables the SS1 to lie relatively flat against the BC. Large, contoured inflate/deflate buttons are positioned on the top of the housing and, according to our test divers, they're comfortable and easy to operate with one hand, even when the SS1 is in your mouth. An efficient purge is located on the end of the unit.

A unique feature of the SS1 is a threaded coupling that enables you to unscrew the inflator/reg from the end of the corrugated hose so you can transport and store it along with your primary regulator and gauges, or easily switch it between your tropical BC and your temperate-water BC. The SS1 also includes a set of adapters and hardware to fit virtually any BC's corrugated hose and remote dump valve assembly. This unit is available in stainless-steel and all titanium versions. The titanium version is lighter and provides added corrosion resistance.