The Quarter Turn That Kills

At least one diver won’t be spending the holidays with family and friends this year, thanks to the dangerous practice of opening a scuba tank valve all the way, only to close it back a quarter turn. According to an article in the Daytona Beach News-Journal, an Edgewater, Florida, diver perished October 9 with more than 140 bar/2,000 psi remaining in his tank. His valve, however, was only open one-quarter turn.

The same thing happened to cave-diving pioneer Sheck Exley over four decades ago. Exley was descending, head-first, into a narrow crack in what is now Wes Skiles Peacock Springs State Park. Exley had accidentally closed his tank valve all the way, then opened it a partial turn, as he was taught. His regulator still breathed fine at the surface but, upside down at 20 m/65 ft, Exley found himself starved for air.

Exley ended up surviving what had been a very close call, and made it a standard of practice in cave diver training to either open valves all the way or fully close them. This has become a standard of practice in tech diver training as well. For reasons passing understanding, however, it has not become a standard of practice in recreational diving.

Where Does This Come From?

It’s common in industries ranging from welding to HVAC to never fully open a cylinder valve. The concern is that, if you try to force open a valve that is already open, you may damage the valve. Well, guess what? If your acetylene valve is only partially open, you may not be able to weld. If your scuba tank is only partially open, you may very well die.

In shallow water, a partially open valve may still be capable of delivering sufficient gas. At depth, however, the same valve setting can leave a diver starved for air.

Forcing a tank valve past its normal stopping point in either direction is a bad idea — even though modern scuba valves are a lot harder to damage than people realize. Curiously, you never hear dive instructors say, “Close your valve all the way and then open it a partial turn.”

In the final analysis, valve damage beats being dead.

So What Should You be Doing?

So that you live to enjoy another holiday:

• Open and close scuba tank valves only by turning them very gently. Stop as soon as you feel resistance. A valve turnwheel that does not turn easily requires service.

• Make sure your valves are either all the way open, or all the way closed.

• Be wary of well-meaning buddies and even dive boat crew checking your valve position for you. Even divemasters have been known to accidentally close a valve all the way, then open it a partial turn. Because this can work in shallow water, divers may not realize they are at risk until it is too late.

• To help ensure your valve is open all the way, take several deep breaths from your regulator while looking at your pressure gauge. The needle or reading should hold rock steady. If it drops with each breath, your valve is closed. If it fluctuates with each breath, your valve is only partially open. Do not dive until the valve is open all the way.

The next time you run into an instructor teaching this archaic and dangerous practice, set him straight. Better to ruffle some feathers than to bury a dead student.

Apeks TX50. Diver deaths result in changes to Navy Dive Manual, equipment.

Norfolk. Va. -Navy divers James Reyher and Ryan Harris both went down together, to a rare scuba diving depth of 150 feet, to finish a training mission needed for a deployment–but they didn’t return to the surface alive.

The dive that killed the two sailors was unprecedented according to the Command Master Diver of EOD Group 2, more than 31,000 dives have been performed by their command . Never before had there been a training dive done at that depth in the last five years.
The question now is whether the decision to take the risk and do the deep dive is enough to charge the 2 senior leaders of Company 2-3, Mobile Diving and Salvage Unit 2 with involuntary manslaughter.
The unit’s master diver, Senior Chief James Burger, and the officer-in-charge, Chief Warrant Officer Mark Smith, are facing a possible court-martial for their role in the decision-making process that led to the deaths.
After two days of testimony, the Article 32 hearing for both men was formally closed Thursday afternoon.
New details emerged during questioning from Navy investigators, who say there are two possible theories for why Reyher and Harris died.
Their connecting rope to the boat above could have gotten tangled around something inside the Superpond at Aberdeen Proving Ground. A survey of the bottom by NCIS agents found metal beams, copper wire, and other hazardous obstacles that divers could get stuck on.
Investigators also think both of Reyher’s breathing regulators weren’t working when they got to the deeper depths. That regulator is the Apeks TX-50.
During the hearing, it came to light that several of Reyher and Harris’s rescuers also had problems using the same type of regulator, either not giving enough air or freezing over while trying to get down to save them.
The Navy has since barred the use of that regulator in cold water diving.
According to witness testimony, though, the equipment failures still came after “deficiencies in decision-making” by Smith and Burger.
When the preferred method of using the MK-16 diving system was no longer an option due to electronic failure, Navy evaluators say they had other options to finish the mission besides scuba.
The Navy’s normal diving limits for scuba are 130 feet, unless a commander can prove operational necessity–but Smith and Burger still went ahead with what many witnesses called “a dangerous dive.”
After the February deaths, the Navy diving manual was actually changed, to specifically state that “there is no such thing as an operational necessity in training,” to make sure this never happens again.
The investigating officer of the Article 32 hearing will take about two weeks to make his recommendation on whether the involuntary manslaughter or dereliction of duty charges are proper in this case.

Then, it will be up to the commanding officer of Naval Expeditionary Combat Command at Little Creek whether to actually convene a court-martial.

“Always analyse your gas” – Statement from the NACD - August 13, 2013

Following a recent fatality at Ginnie Springs, the National Association for Cave Diving has issued the following statement.

NACD Gas Analysis Advisory

The recent death of a cave diver highlights the necessity to review some critical procedures that we should be doing before all dives – gas analysis. A couple of years ago there was a cave diver death in Cozumel that resulted from breathing high carbon monoxide content in a cylinder. This created quite a commotion that caused the sales of CO analyzers to jump quite a bit. These days it’s not uncommon to see divers analyzing their cylinders for CO during the pre-dive process. However, even with that awareness it is a bit surprising that there are still divers that do not analyze all cylinders for oxygen content. While the NACD does not have courses for mixed gas procedures diving at this time, all NACD instructors should be emphasizing the need for gas analysis during the pre-dive process.

It is always worth having everything you need to hand when analysing and labelling diving gas. 990 Magazine

Divers should re-analyze all cylinders to be used on a dive at the site during the pre-dive process and make sure the cylinders are properly labeled with oxygen content, helium content (if any helium in the blend), and MOD. This should occur even if the cylinders were personally filled by the diver. Each and every cylinder should be analyzed and clearly labeled, even if there is an isolator connecting the cylinders, and regardless what gas is believed to be in the cylinder.

While it is understood that not everyone may own enough cylinders to permanently mark them with content and MOD, cylinders being used for 100% oxygen should be permanently marked and only used for 100% oxygen. However, permanent markings do not substitute for additional labeling. Even permanently marked cylinders need to be analyzed and labeled with content and MOD to show confirmation of the contents. There should never be any confusion about labeling. It should be clear and concise to anyone who looks at it.

Finally, there is some controversy over whether gas analysis should be an individual responsibility or a team responsibility. All divers with mixed gas training of any kind have been instructed that all gas should personally be analyzed prior to every dive. Almost every dive training class emphasizes gas sharing with teammates. With that, there is always the potential for a diver to be breathing from a teammate’s cylinders. Gas analysis and confirmation should be a team project during the pre-dive process.

Rosemary E Lunn analysing a Nitrox stage prior to diving Scapa Flow / 990 Magazine

The lessons to take away from this:

1. Analyze every cylinder, whether you think it is filled with air, Nitrox, Trimix, or Oxygen,
2. Label every cylinder with gas content and MOD
3. Remove all old, Oxygen, Nitrox, and Custom Mix labels if the cylinder is to be repurposed.
4. Make gas analysis a team project.

If you are unfamiliar with or out of practice with analyzing gas contact any NACD instructor and request a gas analysis refresher. If you do not have an NACD instructor nearby contact the training committee and we will provide you with an instructor who can help you.

Gas analysis is not an optional activity. Your life depends upon it.

Rob Neto
NACD International Training Director
NACD International Safety Officer

Source: NACD

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