Fifty-two metres flashes up on our computers. On test is Mares’ latest Epic ADJ 82X regulator. Nick Balban, my buddy and co-tester, is thinking very seriously about taking it off the stage tank it’s on and putting it on my cylinder. And, no, Nick isn’t narked. He’s concerned for my safety.
Testing kit means that I find gaps in my knowledge and experience and try to fill them in and improve my test methods all the time. The objective of this final test-dive is to subjectively assess the reg’s performance in a near worst-case diving scenario. Sharing air, at depth, at low tank pressure.
The Epic ADJ 82X is EN250A-certified. This test is carried out by an independent agency using an ANSTI breathing machine.
Firstly, the regulator is breathed 25 times over one minute, with the volume of each breath set at 2.5 litres, to evaluate its use by a single diver. The test concludes at a simulated depth of 50m.
This meets the EN250 standard any regulator sold in the EU must meet, but attaining EN250A requires an additional test, simulating one diver breathing off the primary second stage and another breathing simultaneously from the octopus at 30m.
The first stage must supply 125 litres of gas in 60sec without exceeding a certain level of inhalation and exhalation effort, called work of breathing.
The lab test is supposedly objective, but it does have critics who suspect that some regulators bearing the EN seal of approval are actually substandard performers. On the back of the VW emissions and other scandals, such cynicism is unsurprising.
Others feel that the EN breathing requirement is set too low. The vital capacity of an average male’s lungs – the maximum volume of air you can shift in and out in one breath – is 4.5 litres, not a paltry 2.5.
However, when working hard, we breathe shallower, partly accounting for the difference. In fact it was our own Health & Safety Executive that fought for the European standard to be set at 2.5 litres rather than 2, so there was a dispute, suggesting uncertainty, even among the experts when setting the standard.
Additionally, under water our breathing efficiency is about halved at 30m, and many leisure divers not only pass 30m but do so without carrying independent bail-outs, leaving a buddy team dependent on an octopus in conditions untested by officialdom. That’s the reality – I do it myself.
So EN250A needs to be seen as a minimum and, arguably, inadequate standard. I believe it’s all too easy to stray outside that safety envelope.
Accordingly, Mike Ward and I aren’t meant to take manufacturers’ claims on trust. DIVER has in the past uncovered serious equipment concerns, such as exposing the inaccuracy of depth gauges in cold water that could have led divers to get bent. Our job is to look for flaws in test kit and report them.
That’s why Nick and I were trying at 52m to outbreathe the Epic ADJ 82X – it’s called “beating the lung”.
The Epic ADJ 82X title refers to the pairing of Mares’ Epic ADJ second and 82X first stage – you can mix and match these with other Mares options to get lower-priced combos.
Mechanically, the 82X is a balanced-diaphragm type, a design associated with high performance. It’s heavy duty, in fact butch.
The test unit had a 300 bar DIN fitting. The handwheel made for an easier grip than other DIN valves I’ve used, so was easy to mount and unscrew from the tank with wet hands.
The dust-cap screws on rather than just push-fits, so is very secure. A yoke fitting is available, though I would prefer to buy the DIN version and carry a screw-on adapter if required.
A built-in device automatically closes off the inlet when the reg is depressurised, so water shouldn’t get in should the first-stage be dunked in a rinse-tank uncapped.
Two high-pressure ports sit either side – I attached a hosed pressure-gauge and a computer transmitter to them.
Mares 82X first stage.
Four medium-pressure ports are mounted on a swivel turret, helping the hoses align for your preferred routeing. I used these to feed my primary second stage, Mares Loop octopus and two direct-feeds for my BC and drysuit. Swivel turrets are uncommon on balanced-diaphragm models, so it’s a praiseworthy touch from Mares.
A fifth mp outlet sits on the end of the first stage. All those ports make the 82X highly configurable for back- or side-mounted cylinder use.
Balanced first stages are designed to virtually eliminate the breathing vagaries of unbalanced first stages. The latter are cheaper to make and most are piston-operated, so have fewer parts and usually require less servicing.
But they are inclined to get harder to breathe from at low tank pressures, a situation in which a diver sharing air via a safe second is likely to end up.
Balanced first stages have been around for decades, so improving ease of breathing, especially during periods of high demand such as sharing at great depth, is all about refining and tweaking the engineering.
When you inhale, the pressure drops in the first stage, and there can be a conflict when there are multiple simultaneous demands for air, such as for inflating your BC, drysuit, DSMB or lift-bag.
In theory inhalation resistance could increase, so manufacturers sometimes prioritise flow to the port feeding the primary second stage.
Reflecting Mares’ intention to sell this regulator to deep-diving technical divers as well as recreational ones, it claims improved flow rates to all the mp ports, which should mean that you can rearrange the layout of your hoses without compromising ease of breathing.
Passing air from your tank through your regulator drops the pressure in two stages to reach your lungs. This also causes the air to supercool; its temperature can easily be 10° below that of the surrounding water.
Moisture in the air in the tank can freeze and form ice particles that can jam the moving parts, though more common is ice forming on parts of the regulator mechanism in direct contact with the water.
The Epic ADJ 82X is EN-certified for use out of the box in water down to 4°C, and for those who dive under ice Mares offers an additional silicone-filled coldwater diving kit. This isolates the first stage’s external moving parts from water and snow that could freeze and block the mechanism.