If a diver buying a regulator in the U.S. wants to be assured
that it will deliver air under extreme circumstances, he must
rely on the manufacturer’s word. There is no independent
standard, and divers have no access to independent tests. Yet
in the European Union, regulators must pass certain breathing
safety standards to be legally sold. A European consumer can
be assured he is buying a regulator that will supply air when
needed, while an American diver has to trust the manufacturer,
the advertisements and the manual.
In the late 1980s, ANSTI Test Systems in the U.K. developed
a machine to scientifically test regulator performance.
Under hyperbaric pressure at prescribed depths, the regulator
is attached to a breathing machine. The work of inhalation
and exhalation is measured and a computer readout of the
breathing cycle is provided. A regulator must be able to
deliver air to a diver at depth having to breathe hard with
low tank pressure. Some regulators fail at that. This machine
also measures the drop in pressure and effectiveness of the
recovery by the performance of the first stage during the
breathing process. Manufacturers have widely adopted the
ANSTI machine for the purpose of designing regulators to
meet the criteria.
Many regulators that pass EU standards are sold in the U.S.
Three of us recently tested a number of inexpensive regulators
available here that pass these ANSTI tests. George Brown, a
working diver in the Scottish Highlands, is a BSAC National
Instructor. Colin MacAndrias is a PADI Master Instructor. I
have instructor certifications with both those agencies. Going
off the beach at the Aqua-Sport International diving center at the Taba Hilton in Egypt, we took the regulators diving in a
side-by-side comparison to see the differences.
A European diver is assured by the
European Union he’s buying a
regulator that will supply air when
needed, while an American diver has to
trust the manufacturer. |
We tried to beat the regulators by breathing as hard as we
could. We inverted them to replicate a panicking diver who
might stuff someone else’s regulator in his mouth upside-down.
(Inevitably, small amounts of water will enter when the port
opens to release exhaled air. The question is whether this water
has somewhere to drain or whether it interferes with breathing.)
We checked how easy it was to activate the purge valve, and
whether there was a tendency to free-flow uncontrollably when
a second stage was dropped from the mouth. We considered
the overall breathing experience. We got to know how each
stacked up against the others. The tests were briefly interrupted
at times: A giant green, free-swimming frogfish decided to
perch on my head.
As a rule of thumb, piston-type regulators tend to give
bigger gas flows and a faster response, while diaphragmtype
regulators are less inclined to develop operating faults
in very cold conditions. Many had only one high-pressure port, which might make you disinclined to employ a gasintegrated
computer with it. Some had knobs that allow
you to increase the amount of effort needed to draw open
the demand valve. Some had Venturi controls that enable
you to reduce the chance of an exponential free-flow at the
surface that is caused by cleanly flowing air passing the
back of the pressure-sensing diaphragm of the second stage.
A couple were designed for trouble-free use in very cold
freshwater.
Apeks ATX40 DS4 (list price: $595; www.aqualung.com)
One of the few diaphragm-type regulators we tested (and coldwater
rated), it has a dry-sealed first stage with four mediumpressure
ports conveniently positioned. The one high-pressure
port was positioned well away from the others so that there
was room to fit a computer transmitter. The second stage has a
Venturi control.
GB: It proved a good breather and very comfortable. It gave
lots of gas on demand but when inverted, it was almost unusable
because it was so wet. I can’t believe the price!
JB: The air came in a broad flow into my mouth. I couldn’t
beat it no matter how hard I breathed it. Inverted, it was damp
the first time I tried it, but I managed to still use it; if it freeflowed
first, then it was almost totally dry. I felt it was always
on the edge of free-flowing and when it did, the flow of gas was
massive. The Venturi switch should be set to ‘minus’ before
you take it out of your mouth at any depth.
CM: It seemed to be very efficient at delivering air no matter
how deeply I breathed. The purge button gave a very soft
blow of air. It’s very sensitive to demand but you pay for that
because it tends to free-flow immediately if you take it out of
your mouth.
AquaLung Calypso ($275; www.aqualung.com) This regulator
has a simple piston-type first stage with a single high-pressure
port and four medium-pressure ports arranged around
its barrel so that hoses fanned out around it. The second stage
has a Venturi control.
GB: This is an excellent regulator. When really breathing
heavily, I detected a fine mist of water, yet when inverted it
was perfectly dry.
JB: A pleasant breathing experience; there was a voluble
flow of gas that diffused nicely in the mouth. The purge was
strong but the flow of air was equally diffuse too. It was perfectly
dry while breathing from it inverted.
CM: There was very little resistance to inhalation. It gave
a crisp breathe every time. There was never any sign of a freeflow.
Inverted, it gave a minute spray of water. The purge was
very effective but not a tonsil blaster.
Cressi Ellipse Black MC5 ($309; www.cressisubusa.com)
A compact diaphragm-type first stage and an oval shaped
second stage distinguish this regulator. There are a single
high-pressure port and only three medium-pressure ports but
well-spaced for a good hose routes. The neat second stage has
a narrow exhaust-T that could lead to exhaust bubbles interfering
with vision. It has a Venturi control.
GB: Very good, if delicately tuned. It would easily free-flow
when dropped out of my mouth. The purge was easily controlled
and proved reasonably dry once fully inverted.
JB: It delivered more than enough air but in a narrow cone.
I felt that it was quite a damp breath when the regulator was
sideways with the hose side downwards, but once fully inverted,
it was reasonably dry. The purge took a hard push to activate
and the effect was not very strong.
CM: Air delivery was good but it hissed a bit with deep
inhalations. Inverted, it became wet. The purge was very weak.
Mares Rover 12 ($300; www.mares.com) This new regulator
has a diaphragm-type first stage with an overly large barrel
that affords good spacing for the two high-pressure and four
medium-pressure ports. It has a marked port for the primary
second-stage hose. The second stage had no visible metal parts
but it included the bypass tube that obviates the need for a
Venturi control.
GB: I got a comfortable and uniform supply of air across
the whole breathing cycle even when I worked hard. When
inverted, only a slight mist of water was detectable. The purge
was extremely effective.
JB: There were masses of breathing gas available. It was
an eye-opener in comparison to other regulators I still thought
were good. The purge control was a little hard to push but the
purge was very effective. Inverted, it was a little damp but eminently
usable.
CM: An excellent regulator that gave gas with little effort.
There was no splash whatsoever when inverted. The purge
needed a heavy press but once done it had a powerful effect.
Oceanic Alpha8 SP5 ($350; www.oceanicworldwide.com)
This regulator has a piston-type first stage, with one high-pressure
and four medium-pressure ports arranged around its narrow
barrel. The last medium-pressure hose fitted always ended up in an awkward spot. The neat-looking second stage has no
knobs and the mechanism is easily accessed for removal of grit.
GB: This regulator performed perfectly. It gave an excellent
breathe from the surface all the way to 120 feet with an even
supply of gas at all times. There were loads of air and no effort.
Inverted, it was quite useful despite a fine spray of water.
JB: It answered the call when I really tried to beat it by heaving
on it hard. It was not too wet for comfort when inverted and
the purge was easy and effective.
CM: It gave a very good breathing rate with each inhalation
very crisp. It was good at all angles and even when inverted
it was wet but very manageable. The purge gave a sharp full
thrust of air.
Scubapro MK2 Plus/R295 ($285; www.scubapro.com)
A piston-type first stage with water-flow holes big enough for
quick response. It has four medium-pressure ports arranged close together and a single high-pressure port spaced apart from
them. The nice second stage has no knobs.
GB: I gave this full marks in all categories except when
inverted, when I detected a fine spray of water.
JB: It gave a slightly tighter breathe than some of the better
regulators. It also gave a lower frequency sound, probably
indicating the air path was broader. At depth, when I really
breathed hard, it seemed a bit asthmatic, and it squawked at
times. The purge was very progressive, which was nice, but
when it was inverted, I choked on a fine spray of water.
CM: This was a very effective regulator with a delivery of
gas that was nicely diffused in the mouth. I felt no spray of water when it was inverted and the purge control gave a full
effective blast.
Conclusion: Although each of us had our own favorites,
none really stood out above the others. We’d be happy to use
any on future dives. If pushed, we’d single out, in no particular
order, the Oceanic, the Mares and the Apeks (though it is
almost twice the price of the others) as slightly more satisfying
in performance than the AquaLung, Cressi and Scubapro.
John Bantin is the technical editor of DIVER magazine in the United
Kingdom. For 20 years, he has used and received virtually every piece of
equipment available in the U.S. and the U.K., and makes around 300
divers per year for that purpose.