Okay, Everybody, Take Seven Breathe Free or Die NEDU then inexplicably suspended testing (or releasing Performance Diver bites the big one test results), ducking all questions with nice, clear statements such as “We’re not tasked to do that at this time.” While regulator In the late 1980s, the U.S. Hoping for the best possible manufacturers waited — and Navy’s Experimental Diving Unit NEDU rating somewhere down waited, and waited — for another (NEDU) rocked the diving the line, every manufacturer — shot at official NEDU tests, there industry by publishing no-holds- especially those who were bashed were no retakes in sight, and for barred ratings of scuba regula- in the earlier tests — hustled to all anyone knew, there might tors. NEDU was lambasted by the improve its regulators before never be. Frustrated marketing sport diving community for not NEDU had another crack at them. people went out on a limb, stating tailoring its procedures to recre- A lot of engineers went back to a in their ads that their regulator ational divers, despite NEDU’s lot of drawing boards. Since was “designed to meet Navy Class protestations that its mission did NEDU seemed likely to use the A standards,” or some variant on not include evaluating gear for same setup the next time around, that theme. Mares had its own nonmilitary purposes. Better manufacturers measured their Reimers equivalent and used this deserved were the thumps manu- success by tests using NEDU’s own approach very effectively to sell its facturers gave NEDU for supply- protocols. They weren’t taking aptly named Navy regulator. ing air to the test regulators any chances on producing the Things then got nasty. Other though a plumbing system that ideal recreational diving regulator manufacturers, who didn’t have exceeded the flow rate possible only to find that it looked bad on their own NEDU-grade test through a standard scuba tank valve, and for overemphasizing high flow rates at the expense of other important factors, such as Average Work of Breathing stability and ease of purging. 1,500 psi supply pressure Respiratory rate 62.5 liters/minute The tests focused on meeting more 4.5 a goal based on “work of breath- effort PDXL 700 required 4.0 ing,” a computer-derived estimate PDXL 1000 of total respiratory effort using a 3.5 USD SEA-2 USD Micra regulator with a mechanical 3.0 breathing simulator produced by USD Arctic Reimers Consultants. The rating 2.5 depended on the maximum depth 2.0 at which work of breathing Joules per liter 1.5 performance goal standard fail remained within the Navy’s set pass limit. Regulators that could cut 1.0 the mustard at 198 feet of sea less 0.5 water (fsw) were put in Group A; effort required 0.0 those that could make it down to 0 33 66 99 132 165 198 132 fsw, Group B; and so forth. Depth (fsw) Manufacturers who received the coveted Group A rating made the NEDU test results for Performance Diver regulators compared with three USD regulators, including one coldwater regulator most of it in their sales cam- paigns. As you might guess, no company advertised that its benches, tried hard to rip a patch NEDU’s system. They either regulator “qualified in Navy out of Mares for capitalizing on leased time on bench setups Group C,” even though Group C the name, as well as for the ads identical to the Reimers mechani- regulators were still approved for that emphasized the Mares cal breathing simulator at NEDU, military use. regulator’s purported ability to or built their own benches.

©1995 Elephant Socks Publishing, Inc. 7 pass the NEDU test. Insults were To satisfy NEDU, all regula- tors, the PDXL 700 and the hurled, credibilities impugned. tors must also maintain their PDXL 1000. Of course, nobody really knew cracking pressure (initial inhala- The PDXL 700 was wiped off what NEDU would actually find tion resistance) within 0.5 inches the field before halftime. At a until they resumed testing and of water pressure on either side of supply pressure of 1,500 psi and published the results. manufacturers’ specifications at the lowest measured ventilation various flow rates ranging from 0 rate (40 liters/minute), the PDXL There They Go Again to 30 cubic feet per minute. Five 700 barely passed the perfor- different samples of each regula- Finally, after a seven-year mance goal for work of breathing hiatus, NEDU has once again at the surface, and was out of the started to test regulators and running by the time it got to 33 fsw. publish results, and as before, At 62.5 liters /minute, the PDXL there are a few surprises in store: Next month: Find out which 700 exceeded the maximum the Navy has raised the bar. Gone regulator failed NEDU’s work- acceptable work-of-breathing, are the letter-group ratings, of-breathing tests, but was even at the surface! replaced with a much simpler, do- judged acceptable anyway, At that point in the game, the or-die scale. Regulators now are because they liked it so much. Navy terminated further testing of on the “Authorized for Navy Use the PDXL 700. NEDU’s report (ANU)” list, or they are not. described it as a “sub-standard- Period. performing regulator, not capable To make it onto the ANU list, tor model are tested at 1,500 psi of meeting Performance Goal regulators must meet the Navy’s on the way down, and at 500 psi on Standard at any depth or ventila- work-of-breathing standard all the the way up. tory rate.” NEDU recommended way down to 198 fsw (in 33-foot that “this regulator be excluded Finally, there is a series of increments) at about 70˚F and from the ANU list.” manned test dives in NEDU’s back up, unless they are specifi- Ocean Simulation Facility to 198 How about its big brother? cally designed for use in cold fsw and in open water to 130 fsw The PDXL 1000 didn’t do very water. In that case, they must to evaluate subjective factors such well, either. At 1,500 psi, it meet the work-of-breathing as fit, function, and feel in various exceeded the maximum accept- standard only down to 132 fsw at positions. able work-of-breathing goal at all 28-31˚F. Cold-water regulators’ ventilation rates, from the surface first stages must not freeze at all, Performance Diver Regulators on down. As with the PDXL 700, and their second stages must not further testing was terminated. fail due to freezing, though minor Performance Diver is a mail- NEDU’s recommendation was free-flow is acceptable. order diving-equipment company “that this regulator be excluded that sells its own line of regulators. The simulated ventilatory rate from the ANU list.” In Technical Report No. 6-94, (lung volume times number of dated April 1994, NEDU pub- breaths per minute) used for Summary lished the results of its tests on pass/fail evaluation in the work- two Performance Diver regula- Both Performance regulators of-breathing tests is 62.5 liters. failed miserably in NEDU’s work- For a diver — remember, we’re of-breathing tests. The amount of supposed to cruise around slowly effort it took to breathe either with minimum exertion under- one exceeded the work-of-breath- water — that’s really honking. An Order Before ing limit (1.37 joules per minute) average person pumps about 6–10 right at the surface. Breathing liters per minute in and out of his Midnight Tonight! effort rose so sharply under water lungs at rest, according to the that NEDU stopped testing both U.S. Navy Diving Manual, The latest Performance Diver catalog regulators without proceeding to although this can increase to 100 lists the PDXL 1000 regulator on sale for the manned evaluation phase. liters per minute “during severe $239.99 and the PDXL 700 for $199.95. The results couldn’t have been work” or “during a short period of Both regulators come with a money-back much worse. . . . extremely forceful breathing.” satisfaction guarantee. Call Performance Diver at 800-933-2299. Delmar Mesa

8 ©1995 Elephant Socks Publishing, Inc.