The Mother of All Reg Reviews - Regulator Test Score Charts

COLUMN A
37.5 Respiratory Minute Volume (RMV) @ 132 fsw: The maximum recreational depth at a somewhat aggressive breathing rate.

COLUMN B
75 RMV @ 132 fsw: The maximum recreational depth looked at as 1) an extremely heavy work rate or 2) simulating two divers buddy breathing at a somewhat aggressive breathing rate.

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

COLUMN D
62.5 RMV @ 198 fsw: The U.S. Navy's Class A test depth and breathing rate, but using a lower high-pressure supply pressure.

"ABOVE & BEYOND"
75 RMV @ 198 fsw: An extreme depth with an extreme breathing rate, stressing a regulator far beyond what any recreational diver can or will theoretically do. This mark is interesting more as an exercise in engineering than as a real-world matter.

SCORING:
Breathing simulators are great indicators of a regulator's abilities, as expressed in EXT WOB (External Work of Breathing, the sum of the inhalation and exhalation effort expressed in joules per liter, or J/L). However, with a machine as accurate as the ANSTI simulator, competing regulators produce a litany of J/L scores differing from each other by a matter of tenths and even hundredths of a point.

So for the sake of simplicity, and to avoid losing perspective in the original goal (which is to isolate good-breathing regulators) by becoming obsessed with decimal points, we've translated J/L scores into three basic classifications: Good, Very Good, and Excellent. Here's what each represents:

3 = GOOD
Any regulator that can achieve the breathing rate/depth category with a EXT WOB of less than 3.0 J/L (the EN250 limit).

4 = VERY GOOD
Any regulator that can achieve the breathing rate/depth category in half or less of the EN250 standard limit, or a EXT WOB of 1.5 J/L.

5 = EXCELLENT
Any regulator that can achieve the breathing rate/depth category with a EXT WOB of 1.0 J/L or less. (While tenths or hundredths of a point of variation between WOBs is detectable only by a machine, a diver in the water can in fact discern the difference in breathing of one-half a J/L, especially when diving at deeper depths. So here we give engineers credit where credit's not only due but actually noticeable to a diver.)

Note: If a regulator is unable to achieve the breathing rate/depth category, the box is left blank and the regulator scores zero for that test.

* = ACHIEVED
Any regulator that can achieve or exceed the "Above & Beyond Mark." (Since this is an extreme test performed under conditions a diver would never experience, it is not factored into the scoring. However, it's nice to know a reg will take anything you can throw at it, plus more.) If a regulator can't reach the 198-foot mark but comes within 25 feet, we list the maximum depth attained at this RMV.

WARNING: Although we're using excessive depths to show both how these regulators perform and their reserve potential, this is not to suggest that you should take them that deep. Scuba Diving doesn't recommend diving deeper than the recreational depth limits.