Author name: Scuba Admin

HOW WE SCORE

ANSTI breathing simulator results shown here are based on a score of 1 to 5, where 5 represents excellent performance with work-of-breathing measurements of 1 joule per liter or less at carefully regulated depths and breathing rates and volumes.

HOW WE TEST

ScubaLab put these regs through two tests — the first is conducted on a breathing simulator, and the second by our team of test divers.

OBJECTIVE TESTING

We conducted tests on an ANSTI wet breathing simulator at Dive Lab, a commercial test facility in Panama City Beach, Florida. The simulator measures the effort (work of breathing) required to move air through a regulator as it is subjected, under- water, to a precise series of depths and breathing rates.

The simulator pressurizes the test chamber to simulate depths of 132 fsw,165 fsw and 198 fsw. Each “breath” by the machine moves 2.5 liters of air through the regulator, at breath- ing rates of 15, 25 and 30 breaths a minute. These precisely measured volumes of air — 2.5 liters multi- plied by the breathing rate — are called Respiratory Minute Volumes (RMVs).

37.5 RMV @ 132 fsw:
This represents the maximum recreational depth at a somewhat aggressive breathing rate.

75 RMV @ 132 fsw:
This simulates the potential demand at maximum recreational depth for a diver at an extremely heavy work rate, or loosely simulates two divers buddy breathing at a somewhat aggressive rate.

62.5 RMV @ 165 fsw:
This represents the European conformance standard EN250, and is also the depth and breathing rate commonly used by manufacturers when determining a regulator’s performance.

62.5 RMV @ 198 fsw:
This is the U.S. Navy’s Class A test depth and breathing rate (although the Navy uses a higher HP supply pressure than we do). The simulator monitors how much effort is required to breathe, measuring the work of breathing in joules per liter (j/l). In our ratings, a score of 1=3j/l or greater; 2 = 2.26-3.0 j/l; 3 = 1.51-2.25 j/l; 4 = 1.1-1.50 j/l; and 5=1j/l or less.

We don’t test on the simulator for a pass/fail grade, but to objectively gauge performance in carefully controlled conditions. You can see how each reg performed on the breathing simulator in the charts that accompany the reviews.

ERGONOMIC TESTING

We conducted these tests at Alexander Springs in Florida with a team of divers who recorded their scores during their dives using underwater slates and waterproof test sheets. Divers evaluated each regulator in 13 specific performance areas, assigning scores from 5 (excellent) to1 (poor), and recording their observations and comments about factors that determine the comfort and performance of the reg while they were actually being used.

ERGO TEST CATEGORIES

1 Ease of breathing in swimming position
2 Ease of breathing in head-up position
3 Ease of breathing in head-down position
4 Wetness in normal swimming position
5 Wetness in head-down and odd positions
6 Bubble interference in normal swimming position
7 Bubble interference in vertical/stationary position
8 Ease of clearing regulator using the blowing method
9 Ease of clearing regulator using the purge button
10 Purge button stiffness and comfort
11 Comfort of mouthpiece
12 Venturi lever adjustment function and effectiveness
13 Breathing- adjustment-knob function and effectiveness

WHAT YOU GET FOR UNDER $500

Regs in this price range tend to be short on frills. None we tested in this price category had breathing resistance adjustments, rotating first stages, swivel hose connections, titanium goodies, etc. In some cases, that means you’re giving up a bit of comfort or convenience, such as the additional options for hose routing that you get with a rotating first stage, or the ability to precisely fine-tune your reg’s breathing resistance at a particular depth and workload. But that’s not to say these regs cut corners when it comes to performance — in our testing some showed work-of- breathing scores on the ANSTI machine and comfort and ease of breathing in the ergo tests to rival regs with much heftier price tags. Of course, their lack of breathing resistance adjustments means it’s especially important that their factory presets strike the right compromise between too much and too little at varying depths and breathing rates. Our testing suggests they usually hit very close to the mark.

WHAT YOU GET FOR OVER $500

The regs we tested in this price range showed slightly higher performance overall on the breathing simulator than their thriftier brethren (principally at greater depths and extreme breathing rates). But testers found that some features on these regs added comfort and convenience. Breathing adjustments allowed fine-tuning airflow with changes in depth or breathing demands. Exotic materials helped keep components light for comfort without sacrificing performance or durability. And first-stage features like rotating barrels or extra ports provided more hose-routing options.

Q: What makes a reg a favorite?

A: As you’d expect for a piece of gear as personal as a reg, test divers have varying opinions. But the regs our testers liked best had controls that were easy to use and effective (and well marked). They had second stages that were compact and didn’t create bubble interference. They had purge controls that could clear the reg effectively without an excessive blast of air. And — above all else — they delivered smooth, quiet breathing, with as little effort as possible.
— Roger Roy, ScubaLab Director

REG CLEANING

Don’t just give your reg a quick rinse after diving — give it a good long soak, especially if you’ve done multiple dives in salt water. Always be sure to give clean, fresh water time to wash away any salt that has accumulated before it can cause corrosion or other damage to sensitive parts such as valves and diaphragms. If possible, soak your reg while it’s installed on a tank and pressurized, which will prevent water from getting inside. If it’s not pressurized, don’t press the purge while it’s soaking because that could let water inside.

PERFORMANCE YOU CAN SEE

The graphs below show results of ANSTI testing on the same reg at different depths and breathing rates. The loops go clockwise, starting at the right, as inhalation begins, and moving to the left, where exhalation starts. Below the centerline shows the negative pressure required to inhale; above shows the positive pressure needed to exhale, measured in millibars.

Photo Illustration by Scubadiving.com

ANSTI Breathing Rates for SCUBALAB

The top graph was taken at 132 feet at 15 breaths per minute, and recorded a work-of-breathing score of .73 joules per liter — excellent performance, showing it was able to deliver air at that rate and depth with little effort. The next graph shows the same reg at 181 feet and a breathing rate of 30 breaths per minute. The denser air, higher water pressure and rapid breathing are taxing the reg, pushing its work- of-breathing score to 1.76 joules per liter — good, but a difference a diver would feel.