21 REGULATORS

THE
DEEP
BREATH
TESTS


Report by John Bantin



Everyone thinks their own regulator is the best, but then they would, wouldn't they?
Few of us get the opportunity to compare how various models and brands of regulator differ in performance at depth. We tend to take the recommendations of other users, dive-shop staff, or even be guided by editorial reviews in certain publications written with what cynics might regard as too firm an eye on advertising.
Things are different at Diver. Once again we have used four independently minded divers in a comparison test under controlled and consistent conditions. They have had the enlightening experience of comparing 21 regulators side-by-side at depth - something few of us can claim to have done.
We asked all the major regulator distributors to supply what they considered the best performer in their range, plus one other of their choice. They sent each one with two identical second-stages, so that our testers could breathe simultaneously from them.
Where some regulators have an over-sized port for the primary second-stage, the additional second-stage was connected to a port normally used for an octopus rig.
Our test divers ate, breathed and slept the 21 regulators (Aqualung sent three - one US Divers, two Spiro) for seven days. I was there as event producer, ensuring that the experiment was conducted fairly and consistently, carrying on my back the cylinders with the extra regulators to be tried during each dive, acting as safety cover underwater, and recording opinions expressed as soon as the group surfaced.
I also took the photographs, some in shallower water during a special "photo-call" dive.
Regal Holidays kindly sponsored the event with flights and accommodation at the Rosetta Emperor Hotel, Sharm el Sheikh. This allowed us to dive repeatedly and uninterruptedly in the clear, deep water of Egypt's Sinai, without the problems of tides, visibility or the sudden onset of poor weather that would have bedevilled us in UK waters, especially in December.
Emperor Divers, the hotel's dive centre, also gave us help, providing free facilities for diving including transport, air and nitrox. The latter added a degree of safety to our decompression, allowing us to do two deep dives a day and compare more regulators than ever before.
We were impressed by the consistency of the nitrox mixes. Emperor also supplied shore-cover, O2 for emergencies and the services of Sarah, who was excused from normal duties to be with us for the week.
We chose the site of a shore dive at Sharks Bay for the test, to avoid the vagaries of boat formalities. We would thus not be affected by the requirements of holiday divers, who would not have wished to dive at the same location every day.
Each of us used twin tanks fitted to Buddy Trimix BCs with Buddy twinning bands, and each regulator was fitted with the two identical second-stages. Working in pairs and with synchronised breathing techniques, the test divers could find out how a model would perform for a user under severe demand, such as with another diver in a panicky out-of-air situation.
Pairs went in armed with two such regulators each on their twinsets, giving them four different models to compare. As "spare" diver I carried two extra sets of regulators - one generally a "benchmark" unit from a previous dive, plus one extra to try.
I would move in with these as required, so each diver experienced at least five different regulators during a single dive, and ten in a day.
On each dive we descended a canyon in the coral wall to the same spot on the sand at 41m for the static comparison test.
The test divers made long and comprehensive notes during dives. Their writing proved perfectly coherent, dispelling any myth that they might be too affected by nitrogen narcosis to make sensible judgments, or indeed function properly!
The dives were of some considerable duration with high decompression penalties, so the divers also had the chance to get to know each of the regulators they carried during the time-consuming ascents needed. All dives were planned and executed with our computers set for air.
Luckily the marine life of the reef dispelled any risk of boredom during long deco-stops. We got to know the cleaning stations and one day enjoyed the spectacle of a large guitar fish and kobia browsing nearby.
George Brown expressed concern that during the fraught moments of a real out-of-air octopus-sharing manoeuvre, a panicking diver might put another diver's second-stage upside-down into his or her mouth. So he was detailed to try each of the tested regulators the wrong way up.
Some second-stages had additional controls, and their manufacturers tended to use a variety of names for these. We have standardised the description by calling them the Breathing Resistance Adjustment (BRA) and the venturi +/- switch.
The latter control is used to discourage a regulator from going into free-flow where it meets the greatest pressure change - at the surface between the air and the water.
The testers made their comments iependently. I edited them down for space and to avoid repetition.
Back in Britain the test continued. Because some regulators tend to free-flow gently while facing into fast-flowing ocean currents, or while decending a shot-line face-first into a current, we took the regulators for a dive in the controlled flow of a swimming pool equipped with the water jet of a hydrotherapy unit.
Now I was the test diver. Holding on to two strops so that I was not pushed away by the force of water, the exercise reminded me of some of my past attempts to water-ski!
Any second stage will free-flow if presented directly into a powerful current. I was looking for the ability to control or stop this loss of breathing air by adjusting the angle of my head to the flow.
Finally each regulator, well dived-in, was taken to the ANSTI machine of AP Valves in Helston, Cornwall. A regulator manufacturer had offered us free use of its facility, but as AP Valves uses its machine only for testing its AutoAir emergency breathing device and has no interest in any particular brand of regulator, this seemed more appropriate.
All regulators now sold in the EC meet the performance requirements of EN250, so we looked at the effort needed to crack open the valve, plus both inhalation and exhalation effort needed at 50m in water at 17*C with a cylinder pressure of 50 bar, which amounted to the work of breathing.
The breathing rate was 25 breaths/minute and ventilation rate 63 litres/minute - equivalent to a large diver working very hard, and probably very frightened!

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The team
From left to right: Novice of the group was Diver's Managing Editor Steve Weinman. A member of the Ariel branch of the BSAC, recently qualified as a Dive Leader, he may after only six years' diving have been the least experienced of the group, but as a journalist of long standing would prove a daunting prospect for any regulator that did not live up to expectations.
Steffi Schwabe, Director of the Rob Palmer Blue Holes Foundation in the Bahamas, is used to diving to extreme depths and in the seriously challenging circumstances of deep cave penetrations.
We knew that her input as someone who demands the ultimate performance from any breathing valve would be invaluable.
Sarah Woodford was dropped in at the deep end when she helped with our recent deep-water computer comparison (Diver October 1997). Until recently the local representative for Regal Diving in Na'ama Bay and Sharm el Sheikh, Sarah has returned to her former skills, working as a diving instructor with Emperor Divers. She is an experienced regulator service technician, qualified to work on a variety of types.
The team was headed by George Brown, BSAC National Instructor and Expeditions Advisor. He is a veteran of the last Diver regulator comparison test.
George is based in Scotland, and often finds himself at work underwater in his role as surveyor for the Highlands Council.

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ANSTI Testing | The Conclusions

Apeks TX40 and TX100 Beuchat Evolution and VS8 Club Cressi-Sub XS1 and F3 Mares MR12 Voltrex and MR22 Ruby Ocean Reef 6600 and Enterprise

Oceanic Delta IID and Gamma D Poseidon Cyklon 5000 and Jetstream Scubapro Mk14/M50 and Mk20/G250 Sherwood Blizzard and Magnum Spiro Ranger XP and Supra D XR2 Cryo, US Divers SEA4 Micra ADJ

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Appeared in DIVER - March 1998.

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