00 S C U B A D I V I N G JULY 2007 JULY 2007 S C U B A D I V I N G . C O M 71
12SCUBALAB REVIEWS
STATE-OF-THE-ART
BREATHERS.
NEWREGS
WOULDN’T IT BE NICE TO DEMO every new regulator before
committing your hard-earned cash? It is, after all, the most important
piece of gear you’ll buy, which puts a lot of pressure on making the
right decision—and that’s where ScubaLab comes in.
We invited all major manufacturers to submit their new regula-
tors (introduced within the last 12 months) for this review. After
inspecting them and reviewing the owners’ manuals we put them
on an ANSTI breathing simulator to measure the precise breathing
resistance a diver will encounter at four different depth/breath-
ing rate settings that range from normal breathing at 132 feet to
extreme exertion at 198 feet. Then we turned the regs over to a
team of eight test divers to be your stand-ins. Their mission was to
rate each reg using a 1 to 5 scale in seven ergonomic performance
categories, from ease of breathing to comfort features. These divers
also made notes on each reg—what they liked and what they didn’t
like. We then polled our test divers to find out which reg in each
price category offered the best combination of features, comfort
and performance and awarded these regs the additional honor of
being named a ScubaLab Testers’ Choice (see “Testers’ Choice &
Best Buy,” p. 73).
The complete results of all our tests are found in the charts on p.
98, and are summarized in the following reviews, which are presented
here in alphabetical order within price categories.
SCUBALAB ONLINE
For more on how
ScubaLab tests regula-
tors, including a detailed look at
how we use the ANSTI machine,
go to www.scubadiving.com/
bonus_2007_reg_test
S C U B A L A B ® R E V I E W E D
BY BILL KENDIG
PHOTOGRAPHY BY JOSEPH BYRD
R E G U L A T O R S O V E R $ 5 0 0
JULY 2007 S C U B A D I V I N G . C O M 73
PROS: Perfect simulator scores; well-designed
user adjustments; built-in electronic intermediate
pressure gauge; reversible hose configuration.
CONS: High price; large first-stage (XTX50
Status).
F IRST STAGE: These are the first regs to
feature a built-in electronic intermediate pres-
sure gauge, complete with an LCD screen that
indicates if the pressure is “HI,” “LO” or “OK”
before every dive. The electronics also track the
date and hours of use to indicate when it’s time
for routine service. Beneath the digital brain
are two different versions of an over-balanced,
environmentally sealed diaphragm first stage
that has plenty of brawn. Both regs offer four
low-pressure ports and two high-pressure ports
for convenient hose routing (low-pressure ports
are on a rotating turret on the XTX50; angled
on the XTX200). Both regs come factory ready
for nitrox mixes up to 40 percent. The XTX50
first stage comes in a bigger, bulkier package,
while the more streamlined XTX200 first stage
is available with a DIN connection.
SECOND STAGE: The pneumatically bal-
anced second stages are identical except for a
few cosmetics—the XTX200 has chrome trim,
the XTX50 does not. Well-designed adjustments
include a large control knob with a wide range
of travel for taking breathing resistance right
to the edge of cracking effort, and a ratcheting
venturi lever that lets you tune out freeflows.
Both second stages also feature a reversible
hose configuration.
TEST DIVERS SAID: The large ratcheting
venturi and the adjustment knob are easy to
find and use, even with gloves. Many test divers
also liked the Comfo-Bite mouthpiece. Clearing
was easy and the purge button was effective
without blasting fillings loose. Breathing was
very dry in all positions, and there was no drop
in performance in various positions.
THE ANSTI REPORT: Both regs aced the
breathing machine panel with a remark-
ably stable performance regard-
less of depth or demand.
P R I C E : $847 for the XTX50
Status; $990 for the XTX200
Status.
A P E K SXTX50 Status and XTX200 Status
72 S C U B A D I V I N G JULY 2007
A P E K SXTX200 Tungsten Swivel
P R O S : Perfect simulator
scores; well-designed user
adjustments; great hose swiv-
el connection on the second
stage; cool-looking protec-
tive finish.
CON: High price.
F I R S T S TA G E : This
compact, environmen-
tally sealed, over-balanced
diaphragm first stage is the
flagship regulator for Apeks—and it looks really
cool to boot. The hardened tungsten PVD finish
is not just for show, it also protects the reg from
the elements. Four low- and two high-pressure
ports are angled for comfortable hose routing
and there’s a brass plaque affixed to the first
stage for a distinct appearance. It’s nitrox-ready
right out of the box for mixes up to 40 percent
and shares the same smooth-breathing perfor-
mance as the regular XTX200.
SECOND STAGE: The Tungsten finish is
also found in the grill of the second-stage cover
and on the adjustment knob. It has all the same
adjustment features found on the other XTX
second stages, plus it comes standard with
a great new hose swivel connection that test
divers loved.
TEST DIVERS SAID: “It felt like the hose
wasn’t even attached,” wrote one test diver
commenting on the swivel connection. As with
the other XTX second stages reviewed here,
the large control lever and adjustment knob
were also a hit.
THE ANST I REPORT: Another perfect
score. The addition of the swivel made no sig-
nificant difference in breathing performance.
PRICE: $965.
A Q U A L U N GKronos
PROS: Compact first stage; simplified user
adjustments; unique side-venting exhaust tee;
ACD dam on first-stage inlet.
CON: Not environmentally sealed.
F IRST STAGE: The Kronos balanced-dia-
phragm first stage offers a full contingent of four
low-pressure and two high-pressure ports, giv-
ing you more flexibility in hose routing and the
option to use both a transmitter and pressure
gauge hose. The first-stage opening features
Aqua Lung’s Auto-Closure Device (ACD), which
closes the inlet to water intrusion whenever the
reg is off a tank. Another nice touch: The yoke
knob is covered with soft rubber for an easier
grip with wet hands.
SECOND STAGE: The new Side-X exhaust
system on the Kronos pneumatically balanced
second stage directs all bubbles to the diver’s
right for clearer viewing. An added benefit is
that warm air passes over the second stage valve
and hose, fighting freeze-up in cold water. The
new Dual Cam control simplifies adjustment by
combining the venturi and breathing resistance
knobs into one easy-to-find lever. While the
range of adjustment is small, it does the job of
stopping freeflows at the surface and fine-tuning
breathing performance underwater. The Kronos
comes with both a Comfo-Bite mouthpiece and
a standard spare.
TEST DIVERS SAID: “The Dual Cam lever
was glove-friendly and prevented surface free-
flows,” wrote one test diver, echoing the com-
ments of the others. Our divers also gave the
Side-X exhaust system a unanimous thumbs-
up. The compact second stage was an easy
breather, stayed dry in all positions and was
easy to clear.
THE ANSTI REPORT: Work of breathing
scores fell into the Excellent category for the
test that most closely represents recreational
diving and the Very Good category for the more
extreme tests. Close inspection of the breathing
loops shows that in these high-volume breath-
ing situations and at depths to 198 feet, the
reg’s inhalation effort was very stable while the
exhalation effort increased only slightly as the
tests got more challenging.
PRICE: $569.
Q: What is a ScubaLab Testers’ Choice?
A: We award the Testers’ Choice logo to the
gear that our team of divers vote as their
favorite combination of fit, features and perfor-
mance based on their extensive in-water use.
Q: How do you determine Testers’ Choice ratings?
A: While in the past we used a complicated points-based system to
determine what gear earned our coveted Testers’ Choice rating, for
2007 we simplified the process. At the conclusion of our in-water
testing, we divided the regs into their respective price groups and
polled our test divers with one final question: “Which one would
you buy?” It’s fascinating to see the wheels turning as each test
diver calculates all the pros and cons and comes up with their indi-
vidual answers.
Q: Does not earning a Testers’ Choice mean gear
is substandard?
A: Not at all. As you can see from the individual reviews and the
charts on p. 98, every regulator tested performed admirably on
the breathing machine, and all were able to stand up to the most
punishing tests. In the ergonomic evaluations, the lowest score test
divers gave any reg in any category was a Good rating. The results
of each review stand on their own and should be read carefully and
completely. Testers’ Choice is merely an additional tool to help you
analyze the results and make an informed buying decision.
Q: What is a ScubaLab Best Buy?
A: While Testers’ Choice is based on the vot-
ing of test divers, Best Buy is awarded at the
discretion of the ScubaLab staff. We award
this logo to the gear that we think is a particu-
larly good combination of performance and price.
Testers’ Choice & Best BuyA:
gear that our team of divers vote as their
favorite combination of fit, features and perfor-
mance based on their extensive in-water use.
A:
ing of test divers, Best Buy is awarded at the
discretion of the ScubaLab staff. We award
this logo to the gear that we think is a particu-APEKSXTX50 Status
APEKSXTX200 Status
R E G U L A T O R S O V E R $ 5 0 0
JULY 2007 S C U B A D I V I N G . C O M 75
PROS: Lowest overall work of breathing; corrosion resistance at a lower cost than titanium; great
second-stage swivel for added comfort.
CON: High price.
FIRST STAGE: The ST1 is a balanced-piston first stage turned from 316 stainless steel that offers
greater strength and corrosion resistance than brass regulators at a significantly lower cost than
titanium. It offers four low-pressure ports on a swivel turret with a fifth port on the end of the first
stage for easy hose routing, plus two high-pressure ports.
SECOND STAGE: The ST1 delivers high performance with a dose of comfort thanks to a
well-designed mouthpiece and Atomic’s Comfort Swivel. It also features all the usual Atomic
features—Automatic Flow Control (AFC), a self-adjusting venturi effect that increases breathing
performance as you descend; the Rapid Adjustment Knob, which allows the user to de-tune the
reg for surf entries or octopus use; a flexible purge cover; and the Seat Saving Orifice, which helps
maintain the reg’s peak performance over time. Inside the second stage, the entire valve body and
lever of this pneumatically balanced second stage is made of corrosion-resistant titanium.
TEST DIVERS SAID: Divers thought the ST1 was one of the “smoothest breathing” regulators of
the bunch and gave it the highest ergonomic scores of all the regulators in this review. The comfort
swivel helped boost comfort scores and test divers had praise for the user control knob and soft
purge cover. This reg also received the highest score for Ease of Breathing and was the only reg
rated Excellent by test divers for dryness. When we polled our test divers for their top reg in the
price category, the ST1 was a clear Testers’ Choice (see “Testers’ Choice & Best Buy,” p. 73).
THE ANSTI REPORT: While several regs in this review earned perfect breathing machine
scores on our 1 to 5 scale, the ST1 can boast the lowest overall work of breathing in every one of
our ANSTI tests.
PRICE: $899.
AT O M I C A Q U AT I C SST1
D I V E R I T EHurricane
P R O S : Compact tech-friendly reg; well-
machined user adjustments; dry breather in
all positions.
CON: Mouthpiece too small for some.
FIRST STAGE: The new Hurricane from Dive
Rite is a cyclone of air in a small package. The
first stage is an over-balanced diaphragm that
is cold-water-ready down to 36F, nitrox-com-
patible up to 40 percent, and comes standard
with a DIN connection. Angled ports put hoses
where you want them with two high-pressure
and four low-pressure fittings. A bright red
cap protects the first stage against overhead
scrapes and aids in diver recognition.
SECOND STAGE: The pneumatically bal-
anced second stage offers multiple adjust-
ments to fine-tune your dive. A large red
venturi control lever puts a stop to surface
freeflows and is easy to use with gloves. The
breathing resistance knob offers a wide range
of adjustment to dial in your preferred flow as
you descend. A comfortable mouthpiece and
a wide exhaust tee are a nice touch.
TEST D IVERS SA ID : Breathing adjust-
ments were “smooth and effective,” offering
“a well-machined feel.” Our test divers also
said the reg clears easily with a powerful purge
action. The wide exhaust tee did a nice job
of directing bubbles away, and breathing was
dry in all positions. The venturi control lever
prevented surface freeflows and opened up
nicely underwater. While the mouthpiece is
soft and comfortable, it was a little small for
many of the testers.
THE ANSTI REPORT: The Hurricane deliv-
ered an Excellent performance in the test that
most closely replicates recreational diving and
Very Good scores in the more extreme tests.
PRICE: $599.
R E G U L A T O R S U N D E R $ 5 0 0
PROS : High performance at a reasonable
price; new tri-material first-stage valve; proven
diver-friendly design.
CON: Narrow exhaust tee allows some bubble
interference.
FIRST STAGE: The Proton 12 Metal has been
one of Mares’ best breathing, balanced-dia-
phragm regulators for years, and it’s still going
strong. What’s new is the “tri-material” first-
stage valve, made of brass and two different
polyurethane compounds. It’s designed to last
longer and perform better than previous ver-
sions. It also has the Dynamic Flow Control fea-
ture, a dedicated low-pressure port that helps
deliver big air to your primary second-stage
hose for easy breathing.
SECOND STAGE: The Proton Metal is the
smallest second stage in this test group, and
its solid metal construction makes this reg well
suited to cold-water diving. The Vortex Assisted
Design (VAD) directs air to the diver through a
bypass tube from the valve seat to the mouth-
piece. The large front-cover purge is smooth
and easy to find, even with gloved hands. The
orthodontic mouthpiece is soft and comfort-
able and the exhaust tee follows the shape of
the regulator, but allows greater-than-average
bubble interference.
TEST DIVERS SAID: It’s hard not to like a
light, compact and easy-to-use reg. The Pro-
ton Metal delivers easy, dry breathing without
the need for user adjustments, and the reg is
comfortable in the mouth. All test divers com-
mented on the ease and function of the large
purge saying it was “smooth and powerful.”
THE ANSTI REPORT: The Proton Metal
earned Excellent breathing machine scores
across the board, another reason this regulator
is still going strong.
PRICE: $450.
M A R E SProton 12 Metal
O M SR250 High Performance
PROS: Environmentally sealed and rugged;
nice adjustment knob; easy clearing.
CONS: Small mouthpiece, some bubble inter-
ference.
FIRST STAGE: OMS uses an environmentally
sealed balanced-diaphragm first stage that is
tech-ready with a DIN connection and nitrox
capabilities up to 40 percent. This compact
performer provides four low-pressure and two
high-pressure ports, angled for easy routing.
SECOND STAGE: The R250 second stage
is light and offers user adjustments for venturi
and breathing resistance control. The large
adjustment knob can dial you right to the edge
of freeflow for crisp cracking effort. The Dive/
Predive venturi switch is easy to find—on top,
just in front of the mouthpiece—but it’s smaller
than most levers in this test group. The small
exhaust tee is streamlined, but didn’t wrangle
bubbles as well as others tested.
TEST DIVERS SAID: Testers said the regu-
lator was easy-breathing and dry in most posi-
tions. Some thought the mouthpiece was a
little small, but most liked the “huge range of
adjustment” the regulator had to offer. Clear-
ing was smooth and easy both by exhaling and
purging, though the front purge cover was “a
little stiff.”
THE ANSTI REPORT: The R250 earned
Excellent breathing scores at the first test point.
At greater depths and breathing
rates the regulator’s work of
breathing numbers fell into
the Good category across the
board.
PRICE: $418.45.
74 S C U B A D I V I N G JULY 2007
R E G U L A T O R S U N D E R $ 5 0 0
76 S C U B A D I V I N G JULY 2007
S C U B A P R OMK11/R395 and MK11/S555
PROS: Excellent performance at a budget price (MK11/R395);
compact first stage; nice second-stage adjustment; smooth and dry-
breathing in all positions.
CON: Some bubble interference.
FIRST STAGE: The MK11 first stage was the smallest of the test group
but held its own, putting up some of the best test scores recorded in this
review. This over-balanced diaphragm first stage features two high-pressure and four low-pressure
ports, two of which are marked “HFP” for pumping out 15 percent greater air flow. Convert to
a DIN connection and you have the makings of a compact tech rig. The big surprise is that the
MK11/R395 came in with the lowest price ($384) but with some of the highest performance, earn-
ing our Best Buy recommendation.
SECOND STAGES: The R395 second stage is light and simple with just the VIVA venturi to adjust.
It uses a large control knob in front of the mouthpiece that’s clearly marked “Dive/Predive.” Inside
the case are a new lever and diaphragm that are designed to reduce friction. The low-pressure
hose can be configured on either the right or left side to customize your rig and the flexible cover
allows for easy purging. The S555 second stage is pneumatically balanced, which translates into
lower cracking effort at depth. The case body and valve lever assembly are designed to prevent
freeze-up and it has the same excellent dive/predive switch as the R395.
TEST DIVERS SAID: Our divers found both regs to be smooth and easy breathers. The easy-
to-locate front purge covers were effective. The mouthpiece was comfortable for most while some
bubbles interfered with viewing in certain positions. Breathing was affected in certain head-up
positions with the R395, but not as much with the balanced S555 second stage. Both regulators
breathed dry in all attitudes. Most telling: test divers voted the MK11/S555 their Testers’ Choice
for regulators under $500.
T H E A N S T I R E P O RT: The
breathing machine loved these
regulators. Work of breathing was
Excellent in all tests, and the regs
turned in almost identical results.
PRICE: $384 for the MK11/R395
and $489 for the MK11/S555.
SCUBAPROR395SCUBAPROSCUBAPRO
SCUBAPROS555
SCUBAPROMK11
S P E C I A L T YR E G U L A T O RS P E C I A L T YR E G U L A T O R
A P E K STek3 XTX50
PROS: Comes in right- and left-side
configurations for twin cylinders; envi-
ronmentally sealed; excellent breathing
performance.
CON: Port configuration is not favorable
for single-tank diving.
FIRST STAGE: The Tek3 first stage is
the first regulator designed specifically for
twin cylinders, offering one high-pressure
port and three low-pressure ports, all on
one side. Consequently, the Tek3 is made
in right- and left-hand versions. It is avail-
able in DIN or yoke configurations and
comes nitrox-ready up to 40 percent. It’s
over-balanced and environmentally sealed
for the most demanding conditions.
SECOND STAGE: The XTX50 second
stage is pneumatically balanced, with
significant user adjustments and offers
reversible hose configuration. The resis-
tance adjustment knob is large and offers
a wide range for fine-tuning. The indexed
venturi control lever lets you ratchet up
the flow on descent and block unwanted
freeflow on the surface. A wide exhaust
tee keeps bubbles out of view and can
be exchanged with a smaller one for use
as a streamlined octopus.
TEST DIVERS SAID: The Tek3 was a
smooth breather and dry in all positions.
User adjustments are “easy to find and
operate.”
T H E A N S T I R E P O R T: The Tek3
XTX50 received Excellent scores in all
breathing machine tests.
PRICE: $1,450 for the Tek3 Complete
set (left- and right-side Tek3 first stages,
two XTX50 second stages, a two-meter
hose, a standard hose and a regulator
necklace); $925 for a matched pair of
Tek3 first stages.
3REGULATOR FEATURES
OVER $500 PR
ICE
WA
RR
AN
TY
MA
DE
IN
1ST
STA
GE
PO
RTS
2ND
ST
AG
E
2ND
ST
AG
E
AD
JUST
ME
NTS
FAC
TORY
-R
EA
DY
NIT
RO
X-
CA
PAB
LE
APEKS XTX50 Statuswww.aqualung.com
$847 Ltd. Lifetime UK Over-Balanced
Diaphragm2 HP 4 LP
Pneumatically Balanced
Resistance Knob RVS* Up to 40%
APEKS XTX200 Statuswww.aqualung.com
$990 Ltd. Lifetime UK Over-Balanced
Diaphragm2 HP 4 LP
Pneumatically Balanced
Resistance Knob RVS* Up to 40%
APEKS XTX200 Tungsten Swivelwww.aqualung.com
$965 Ltd. Lifetime UK Over-Balanced
Diaphragm2 HP 4 LP
Pneumatically Balanced
Resistance Knob RVS* Up to 40%
AQUA LUNG Kronoswww.aqualung.com
$569 Ltd. Lifetime France Balanced
Diaphragm2 HP 4 LP
Pneumatically Balanced
Dual-Cam†
(venturi/resistance) Up to 40%
ATOMIC AQUATICS ST1www.atomicaquatics.com
$899 Ltd. Lifetime USA Balanced
Piston2 HP 5 LP
Pneumatically Balanced
Resistance Knob Up to 40%
DIVE RITE RG3500 Hurricanewww.diverite.com
$599 Ltd. Lifetime France Over-Balanced
Diaphragm2 HP 4 LP Balanced Resistance
Knob Venturi Lever Up to 40%
UNDER $500
MARES Proton 12 Metalwww.mares.com
$450 Ltd. Lifetime Italy Balanced
Diaphragm2 HP 4 LP Unbalanced N/A Up to 40%
OMS R250 High Performancewww.omsdive.com
$418.45 1 Year USA Balanced Diaphragm
2 HP 4 LP Unbalanced Resistance Knob
Dive/Pres-Dive Switch Up to 40%
SCUBAPRO MK11/R395www.scubapro.com
$384 Ltd. Lifetime Italy Over-Balanced
Diaphragm2 HP 4 LP Unbalanced VIVA** Up to 40%
SCUBAPRO MK11/S555www.scubapro.com
$489 Ltd. Lifetime Italy Over-Balanced
Diaphragm2 HP 4 LP
Pneumatically Balanced VIVA** Up to 40%
SPECIALTY REG
APEKS Tek3 XTX50www.aqualung.com
$1,450 (2 complete regs); $925 (LH and RH first stages only)
Ltd. Lifetime UK Over-Balanced
Diaphragm1 HP 3 LP
Pneumatically Balanced
Resistance Knob RVS* Up to 40%
†Dual Cam (combines venturi control with breathing resistance control) * Reversible Venturi System ** Venturi Initiated Vacuum Assist
TEST DIVER RATINGS OF ERGONOMIC PERFORMANCE
ANSTI BREATHING SIMULATOR RESULTS
EA
SE O
F B
RE
ATH
ING
DIF
FER
EN
T P
OSI
TIO
NS
DIV
ES
DRY
BU
BB
LEIN
TER
FER
EN
CE
CLE
AR
ING
B
LOW
/PU
RG
E
CO
MFO
RT
AD
JUST
MEN
TS
A >
37.
5 R
MV
@
132
fsw
B >
75
RM
V
@ 1
32 f
sw
C >
62.
5 R
MV
@
165
fsw
D >
62.
5 R
MV
@
198
fsw
4 4 4 4 4 4 4 5 5 5 5
5 4 4 4 4 4 4 5 5 5 5
5 4 4 4 4 4 4 5 5 5 5
4 3 4 5 4 4 4 5 4 4 4
5 4 5 4 4 4 4 5 5 5 5
4 4 4 4 4 4 4 5 4 4 4
4 3 4 3 4 4 N/A 5 5 5 5
4 3 4 3 3 3 3 5 3 3 3
4 3 4 3 4 4 3 5 5 5 5
4 3 4 3 4 4 3 5 5 5 5
4 4 4 4 4 4 4 5 5 5 5
Rating System: 5=Excellent 4=Very Good 3=Good 2=Fair 1=Poor
98 S C U B A D I V I N G JULY 2007 JULY 2007 S C U B A D I V I N G . C O M 99
I N D E P T H
How We Test RegulatorsANSTI Breathing Simulator The ANSTI machine is the international industry
standard for scientifically evaluating a regula-
tor’s performance. It measures a regulator’s
work of breathing (WOB) in joules per liter (j/l)
for each complete inhale/exhale cycle. We test
regulators at four different RMV/depth com-
binations (RMV stands for Respiratory Minute
Volumes, basically the amount of gas that can
be ventilated through the lungs in one minute).
All simulator tests are performed at a supply
pressure of 725-760 psi. If a regulator can per-
form well at this supply pressure, it will perform
as well or better at higher supply pressures.
Here are the tests and what they represent:
» COLUMN A 37.5 RMV @ 132 fsw. A some-
what aggressive breathing rate at the maxi-
mum recreational diving depth. A physically
fit recreational diver might breathe at this rate
while swimming a long distance. (A relaxed
diver on a drift dive will probably be breathing
at 22 RMV or less.) A diver could theoretically
maintain 37.5 RMV for five minutes or longer
without becoming significantly winded.
» COLUMN B 75 RMV @ 132 fsw. An extreme-
ly aggressive breathing rate at the maximum
recreational diving depth. A diver in excellent
condition can breathe at 75 RMV for about one
minute. This test represents how a reg might per-
form with a single diver breathing at an extremely
heavy work rate. It also serves as a loose simula-
tion of the stress a reg would be under if two
divers were breathing off the same first stage in
an air-sharing situation. Only the U.S. Navy and
ScubaLab use this breathing rate to help identify
the outer limits of a reg’s performance.
» COLUMN C 62.5 RMV @ 165 fsw. All regs
sold in the European Common Market must
pass a test standard known as EN250, which
uses this RMV/depth as its benchmark. For this
reason, it’s also the depth and breathing rate
most commonly used by manufacturers to test
regulators. This is a very aggressive breathing
rate. A recreational diver in excellent condition
chasing a bat ray through open water would
probably be able to maintain 62.5 RMV for only
a few minutes.
» COLUMN D 62.5 RMV @ 198 fsw. This is the
U.S. Navy’s Class A test depth and breathing
rate, although we use a lower supply pressure
(725-760 psi). We conduct this extreme test (no
diver should ever be breathing this aggressively
at this great a depth with this little air left in
his tank) to explore the outer limits of a reg’s
performance.
Our test parameters state that the highest
inhale or exhalation pressure experienced by
the “diver” should never exceed 25 millibars
or a total WOB of 3 j/l. If a reg exceeds either
parameter, it “fails” our test, but that doesn’t
mean that it stops delivering air—only that the
breathing resistance at some point in the cycle
is higher than what is common for most mod-
ern regulators.
A machine as accurate as the ANSTI simu-
lator can accurately differentiate j/l measure-
ments to tenths and even hundredths of a
point. Human divers, however, can’t. For the
sake of simplicity, we translate j/l measure-
ments into scores on a 2 to 5 scale as follows:
5=EXCELLENT: A total WOB of 1.05 j/l or
less.
4=VERY GOOD: A total WOB of 1.06 to
1.55 j/l.
3=GOOD: A total WOB from 1.56 to 2.25 j/l.
2=FAIR: A total WOB of 2.26 to 3.0 j/l.
Ergonomic Tests: The Human FactorBreathing machines tell only half the story. To
gauge the ergonomic traits of regulators, we
use a minimum of six test divers. Each diver rates
each reg for user-friendliness in seven areas:
» EASE OF BREATHING: How well a regu-
lator delivers air in the standard swimming
position.
» DIFFERENT POSITIONS: How the regula-
tor breathes when the diver is in a heads-up or
face-down position.
» DRYNESS: Does the regulator breathe wet
or dry in both a normal swimming position and
odd swimming positions?
» BUBBLE INTERFERENCE: Considered
while looking down, straight ahead, up at a
45-degree angle and straight up.
» EASE OF CLEARING: Divided into two
parts: 1) How easy is it to find and use the
purge button, and how forceful is the purge?
2) How much force is required to clear the regu-
lator using the blowing method?
» COMFORT: Test divers rate the comfort of
the mouthpiece, the feel of the second stage in
the mouth, hose lengths and stiffness.
» ADJUSTMENTS: Are adjustments easy to
find, grip and turn? Do they do their job in a
reasonable manner?
Performance is recorded using both numeric
scores on a 1 to 5 scale (5=Excellent, 4=Very
Good, 3=Good, 2=Fair, 1=Poor) and written
comments.
ATOMIC AQUATICS ST1www.atomicaquatics.com
SCUBAPRO Mwww.scubapro.com
SCUBAPRO MK11/R395www.scubapro.com