Any time you fill a tank with nitrox, it must be identified as such. This will help to prevent accidents in the event that someone uses a tank filled with nitrox without taking the proper precautions.
by Jon Kieren
People make mistakes, it’s human nature. I make them all the time. I’m sure that even after this article has been edited several times and published someone out there will find at least a couple of typos and call us out on it. A typo is one thing. However, a simple mistake in the blending process can result in a diver breathing a mix with significantly more or less oxygen than they had expected, causing serious injury or death. If we KNOW that people make simple mistakes so often, then why do so many nitrox divers today NOT analyze their gas before diving? There are two primary reasons: either they don’t understand why it’s so important (a topic that is covered in every nitrox course), or they have just become complacent. This article will discuss both scenarios and how to avoid them.
Why is it so important to analyze your breathing gas? Simply, it can kill you if it’s wrong. If the oxygen content is less than the diver had expected, they can end up with unexpected and unknown decompression obligations.
Example – You make a dive to 30 metres/100 feet assuming you’re breathing 32% nitrox. You spend 39 minutes on the bottom and surface with no decompression obligation. Unfortunately, the nitrox tank you were diving was accidentally filled with air (21% oxygen), and in reality you just blew off 26 minutes of decompression. A significant error that is almost sure to result in Decompression Sickness. This situation can be made significantly worse by conducting repeated dives.
What if the oxygen content is HIGHER than you expected? Should be better off then, right? As far as decompression obligations are concerned, yes. However, a far greater risk in diving nitrox is Oxygen Toxicity and can cause severe convulsions (not a good situation underwater).
Example – Using the same dive as above, assuming you were on 32% nitrox at 30 metres/100 feet, your partial pressure of oxygen (PO2) would be close to its upper limit at about 1.3 ata. If that nitrox mix was in fact a 50% nitrox mix, your PO2 would now be over 2.0 ata and would be considered extremely dangerous.
The examples above are not the only concerns of breathing the wrong gas at the wrong depth; a thorough nitrox course will cover the others, as well as how to avoid them. So if you have to be Nitrox certified to dive nitrox, and the risks and proper procedures for avoiding those risks are covered in the course, why do people still end up breathing the wrong gas? The simple answer is: complacency. Over time, divers become complacent with their gas analysis procedures and start to skip it altogether, which means they end up in the water with absolutely no idea what they are breathing. Pretty scary.
Normalization of deviance is a term used by astronaut Mike Mullane (*Mullane 2014) to describe the process of complacency in safety procedures. In brief, it explains how humans have the tendency to take shortcuts due to different factors including time, peer pressure, etc. Once this shortcut is taken and nothing bad happens, the brain will incorrectly assume that the shortcut is “safe”. This shortcut now becomes the norm, and we have completely eliminated a critical step in a procedure. This applies to diving at every level. How many times have you seen divers jump in the water without doing a proper predive check? It is taught and its importance stressed in every open water course, yet it gets skipped every day because so many divers have “gotten away with it” they assume it’s safe to dive without making predive checks and then eliminate it from their procedure. Unfortunately, it also results in emergencies from divers forgetting to turn on their air and inflate their BCDs.
The same happens to nitrox divers. Maybe one day they are in a rush and forget to analyze their gas at the fill station. They get to the dive site and realize that they forgot to analyze but now do not have access to an analyzer. They are left with two choices, either not dive today or dive without analyzing their gas. The diver has been getting fills from that fill station for years and has never gotten the wrong mix, so they decide to dive anyway and assume the fill is correct. Nothing bad happens, so they now believe this shortcut is safe. “If I get my fills from XZY Dive Center, I know that it will be correct and I do not need to analyze my gas”. They have eliminated the most critical step in diving nitrox, and this is now the norm.
We know people make mistakes, and that’s why we have safety procedures in diving. These procedures help us catch the little mistakes before they create catastrophic emergencies. When diving nitrox, analyze every tank before every dive without exception. It could save your life.
* Mullane, Mike. (March 2014). Stopping Normalization of Deviance.
Is Your Dive Team Prepared? Come find out at FDIC. Emergency Response Diving International (ERDI) will be at booth #2749
This year, International Training (ITI) will be exhibiting at the Outdoor Adventure Show (OAS), Toronto, Ontario. The OAS is the largest consumer show of its type in Canada, with over 30,000 visitors attending last year’s event. Cris Merz (National Sales Manager) and Steve Moore (HQ Training and Regional Manager Eastern Canada) will be representing the agency throughout the show, with the assistance of local SDI/TDI/ERDI facility staff. Please come along and visit us at Booth 419 in the SCUBA World section of the show – we’d love to see you!
The OAS is being held in The International Centre, Hall 5, 6900 Airport Rd, Mississauga, Ontario on 24th, 25th and 26th February 2012. Full details, including directions, can be found via the following link: https://www.outdooradventureshow.ca/toronto/visitor/index.html
Buck Buchanan from Georgia recently attended FDIC and worked the ERDI booth during the event March 24th through the 27th at the Indianapolis Convention Center. Also in attendance at the FDIC show on behalf of ERDI was Regional Manager Shawn Harrison and BOD Representative Nestor Palmero.
The activity at the ERDI booth continues to grow exponentially every year, but this year it was different. There was one topic that was on every ones lips if they were involved in purchasing and procurement…budgets!
It’s no secret that many municipalities and their staffs have been impacted by the home value roll backs and therefore the short fall of tax dollars. One thing that was an over the top hit for ERDI was the growing numbers of online courses that help fulfill the academic requirements without requiring additional OT requirements.
This year’s FDIC had a very unique element for ERDI, on Friday Morning Buck Buchanan entered the booth and stated, “I’ll be back in a bit, there is something I have to do”. As he walked away we wondered where is he going with that Scott Pack?
Upon his return here is what Buck had to say….
“I found out about the 110 story climb as a memorial to our 343 fallen firefighters/brothers that gave their lives on 911 and decided to honor their memory and the memory of a particular man. Each of us making the climb carried the picture of a fallen firefighter. I had the opportunity to meet some of his family members and thank them for their courage and that of their firefighter. I climbed those 110 stories’ in full turnout gear with a Scott Pack because that’s what they did that day in September 2001.
I was lucky to meet a thirteen year old girl who was attempting the climb for her father a firefighter and as is so often the case, you never know how what you do will effect others, this was a hard climb to the top tier of the Lucas Oil Stadium and as the motto said ‘we climb because they climbed‘ after the two hour climb this old PSD… who sometimes wonders if people really care, was approached by this sweet young angel and she asked if I would take a picture with her because she viewed me as an inspiration during the climb. She said “you never stopped, you never quit, you just kept going and I thought if you could do it with all that gear I could do it too” I told her I had girls at home about her age and showed her the picture of my wife and girls and reminded her on 911 our brothers did not stop … and then it hit me!
OUR brothers… those 343 brave souls climbed that day for the same reason I climbed 9 years later… our wives, kids, community and the brother next to you.
As it turned out that little girl, who was there one minute and gone in a flash will never know that she was the true inspiration on that day! Her kind words and bright spirit let me know people do care and my brothers, those 343 firefighters may have fallen but they will never be forgotten.”