Helitrox for PS Diving – Clear Head, Clear Mind in Deep Recoveries?

by Thomas Powell

Thomas Powell PSD Training photo

In the public safety world, gas fills can become complicated. Fire stations must follow OSHA regulations, and fill station operators require training that is not required in standard dive shop environments. If a person were to speak to most current dive team leaders in the United States, they would insist that mixed gasses of any sort, and even basic nitrox, are not allowed in public safety diving programs. Extensive research will show that, in the majority of cases, there are no standing rules preventing the use of nitrox or mixed gas. The reality is that not every public safety dive team has easy access to a fill station. The difficulty acquiring basic air scares team leaders and oversight bodies away from the complications of obtaining gasses that may be even harder, and more expensive, to acquire.

Helitrox is a breathing gas made up of nitrogen, helium, and oxygen. The proper mixtures of these gasses can allow a diver to function and operate at depths beyond the range of standard air fills. In the modern world helitrox is often used by technical divers or commercial divers undergoing complex and often deeper dive activities. To perform technical dives using helitrox, a diver must understand the physiology associated with how the gas can affect the human body underwater, and how to plan for a dive that may involve soft or hard ceilings. To date, advanced mixed gasses have rarely been used in public safety dive training programs or operations. Despite this fact, roughly one year ago, the entire world saw a group of commercial divers, diving helitrox, recover a man who had been submerged in a trapped shipwreck for three days. The gas being used allowed divers to remain underwater and perform an unplanned recovery.

The United States is bordered by two major oceans and consists of a vast number of deep waterways within her interior. When looking at these bodies of water, operational dive teams must recognize that one day they may be called to perform a recovery, or even a rescue, at depth. Imagine that a diver has been trapped at depth while diving helitrox. If a rescue is possible, the team performing the operation must understand the physiology associated with the gas being inspired by the victim. This knowledge will allow the dive team involved to best plan a rescue and return to the surface that does not exacerbate already existing problems.

Similarly, certain bodies of water in the United States exist at altitude. This factor makes even recovery operations go off standard “table diving” scenarios. Essentially, a one hundred foot (deep) recovery dive may be converted to a deeper theoretical depth based on altitude. This factor suggests that divers at altitude may be safer if they have a good knowledge base and understanding of how to use mixed gasses. One of the most interesting things to do with a diver is to let them do comparison dives between helitrox and air. Essentially, let the diver do a dive on helitrox and then later do a dive on air. Then have the diver determine which dive is more memorable. The helitrox dive will be better remembered. This scenario shows that helitrox allows a diver to remain more “clear-headed.”

In the world of public safety diving, being clear-headed and cognizant of all operational activities could save a life. These divers already perform activities in near-zero visibility using a sense of touch. If a problem arises, a clear-headed diver may be more prepared to correct issues or solve problems. Similarly, a clear-headed diver may better remember dive-related details essential to a courtroom scenario.

There is no reason for a dive team to avoid gaining improved levels of knowledge. In many cases, leadership personnel will establish a goal for public safety dive teams. This goal may be the completion of a course such as ERD II. Once that goal is achieved, leadership often turns to team status maintenance. New divers get trained, and current divers do in-service training. This mindset often leads to a lack of focus and the establishment of a normal routine. Education requires a break from this routine and a focus on continued improvement. Even if a dive team does not dive mixed gasses on a regular basis, an understanding of the related dive theory will help dive team members better acknowledge how gas can affect the human body.

Mixed gas diving requires strong education and a focus on learning how to be safe at deeper depths. Despite this, helitrox can allow emergency response divers to perform activities for longer periods, with clearer minds, at deeper depths. A dive team must determine if mixed gas diving could play a role within its territory, and then consider if the team wishes to be available for extended range calls for help in an area exceeding local territory boundaries. At altitude, helitrox diving may be essential to remain safe. Closer to sea level, helitrox diving may be an activity that is beyond the skills set desired by a team. Team leaders must work to make the best decisions possible in regard to team capabilities and knowledge bases.

In North Carolina, the staff at Air Hogs Scuba is working with various dive teams to begin developing a better understanding (for team members) of how gas affects the human body. Three teams are currently working through the TDI Nitrox program as a starting point. The objective is to learn the math, and better understand how to draw personal conclusions regarding how to dive differing gas mixtures. This course is the entry-point for dive teams considering mixed-gas response capabilities. No dive team should turn down educational opportunities provided within reasonable parameters, and helitrox has its place in public safety diving. The reality is that teams have to make the move to become more educated and step outside normal training parameters. Actions of this type will give dive teams greater capabilities, and an improved potential for performing operational activities in expanded environments.

-Thomas Powell
Owner/Instructor Trainer – Air Hogs Scuba

ERDI Divers Honored with the Medal of Meritorious Service

2_officers_receive_medal-of-honor

The Medal of Meritorious Service was bestowed upon two Emergency Response Diving International (ERDI) Instructors, Mike Franklin and Dale Autry, by Oklahoma’s oldest law enforcement organizaion: the Oklahoma Sherrif’s and Peace Officers Association (OSPOA) on February 21, 2014.

This prestigious award was presented to Franklin and Autry after a Rapid Water Callout where they saved the life of a Intensive Care Unit (ICU) nurse while on her way to work. The nurse’s vehicle was caught in swift water and washed down stream as she was unable to escape. Franklin and Autry note she was near death by the time they arrived.

Although many deserving officers save lives every day, the many factors leading up to this call out set Mike Franklin and Dale Autry apart for the Medal of Meritorious Service.

ERD Instructor Workshop for the Virginia Port Authority

ERD Virginia Port Authority Class

Please welcome our new instructors from the Virginia Port Authority class:

Frank White, Steven Curry, George Yates, Fred Simpson, Bryan Miers, Brian Decker, Danny Turnquist, Mark Robinson, Michael Derwent, Russell Dunton, Steve Callow, Steven Dooley, Terry Chambers, Todd Day, Wallace Chadwick, William Engstrom, James Scholten, Pelham Felder, Reo Hagood, Charles Perry, Karl Kassel, Jeremiah Johnson. Instructors: Buck Buchanan, Shawn Harrison, assistant Benjamin Dobrin.

Dive911 along with Emergency Response Diving International™ conducted an ERD Instructor workshop for the Virginia Port Authority earlier this year consisting of multiple jurisdictions of Law Enforcement and Fire Departments.

Buck Buchanan from Dive 911 stated, “It was an absolute pleasure working with this group of instructor candidates. . . Candidates received 100 and 250 hours of training over a space of 3 months, the program ended successfully with everyone gaining the rating of SDI and ERDI Instructor.”

Special thanks go to Bill Burket, Jr of the Virginia Port Authority for helping put this together.

Upon successful completion of this course, graduates may teach courses for all approved SDI™ and ERDI™ levels, including conducting Ops Components. The course is intense and challenging, but very rewarding.

Surface Supplied Air Event with US Border Patrol and Phoenix Police

by Shawn Harrison

USBP logo

In February I had the pleasure of being invited to sunny Arizona in order to attend an event that the US Border Patrol (USBP) and Phoenix Police Department (PPD) where holding. Both teams were conducting a joint training event on Surface Supplied Air (SSA). Mike Buck, a member of the US Border Patrol’s BORSTAR team, was informing me that all members of the Tucson BORSTAR’s Subsurface Maritime Operations Group in this class received training on SSA. He further stated that “this training conditions our team for multiple scenarios that we may encounter, and we need to be prepared to respond.” They also realize that SSA requires specialized training. Moreover, the deployment of the system into various environments would provide additional safety factors.

 

As part of the training they had scenarios set up in which they would deploy from shore in boats and even small Zodiacs (as you can see from the picture below). One of the scenarios involved a vehicle that had been submerged into the water. After searching and locating the vehicle, they realized it was full of drugs bundled in burlap bags (the bags where stuffed for simulation of course). They would then deploy a diver to extract the material from the car. Come to find out, this is a real situation they might face.

During the scenario, the SSA diver would deploy from the boat as the tender would guide the diver to the suspected search area. A search pattern was used to slowly work the diver back towards the objective. The diver is attached to an umbilical line which contains the air hose, as well as a safety line and communication line. The communication line is hard-wired into the system making it more reliable than wireless systems. The diver has an emergency bailout bottle mounted on his back; also the umbilical line can act as the search pattern line.

The majority of public safety dive teams train using Self Contained Underwater Breathing Apparatus (SCUBA) equipment, and both the US Border Patrol and Phoenix Dive Team are trained in both SCUBA and SSA. This was a great opportunity to see the two teams working together and sharing information with each other.

I would like to thank George Herr, David Jordon and the Phoenix Police Department’s dive team, along with Mike Buck and all the US Border Patrol BORSTAR dive team members for allowing me the opportunity to take part in this event.

Contact SDI TDI and ERDI

If you would like more information, please contact our World Headquarters or your Regional Office.

Tel: 888.778.9073 | 207.729.4201
Email: Worldhq@tdisdi.com
Web: https://www.tdisdi.com
Facebook: www.facebook.com/PublicSafetyDiving

How to Switch your Diving Gas

Choosing the Best Decompression Gas

By Jon Kieren

gas blending room

There are many factors that need to be considered when choosing decompression gasses for a dive. The dive profile, logistics, environment/site conditions, and personal preference all come into play; how do these factors affect our decision? First, we need to take a brief look at why we use different gasses for decompression to begin with, and then how the factors previously listed affect our gas choices. For big dives with extensive decompression obligations, it’s often a balancing act between oxygen exposure and off gassing.

Why switch gas anyway? This takes a brief lesson in decompression theory to explain; we’ll focus mainly on the off gassing portion of the dive. The rate of off gassing is related to the partial pressure within the tissues of the body and the partial pressure of the gas being breathed. When the partial pressure of the inert gas (mainly nitrogen and helium) in the lungs (the gas we are breathing) is LOWER than the partial pressure of the inert gas absorbed in our tissues, the gas will move from the area of high pressure (our tissues) to the area of low pressure (our lungs) and be expelled when we exhale.

There are two ways we can reduce the partial pressure of the inert gas in our lungs. First, is by ascending and letting Boyle’s law take over. As the gas expands as we ascend due to reduced ambient pressure, the partial pressure of the gas drops. This works but is not the most effective method. If we ascend too far or too fast and the ambient pressure decreases too rapidly, bubbles can form causing decompression sickness. The second method of reducing the partial pressure of the inert gas in our lungs is to reduce the fraction of the inert gas in our breathing mixture. In order to reduce the fraction of inert gas in the mix, we increase the fraction of oxygen. By switching to an oxygen rich gas on the ascent, we reduce the partial pressure of the inert gas in our lungs and increase the rate and efficiency of off gassing. So, more oxygen=less inert gas=faster/more efficient deco. Got it?

Okay, so if a higher fraction of oxygen is better for decompression, why don’t we just use 100% oxygen for the entire ascent? It would sure reduce our decompression times by a significant amount, wouldn’t it? Well, unfortunately we have to be cautious of the pesky oxygen free radicals caused by breathing high partial pressures of oxygen. If these oxygen free radicals are left to cause damage faster than the body can repair it, oxygen toxicity can become a serious concern. In short, the higher the oxygen content in the breathing gas, the shallower it must be breathed. As an example; for sport and technical diving applications, the maximum operating depth of oxygen is 6 metres/20 feet; and the maximum operating depth of 50% nitrox is 21 metres/70 feet. Here’s where we begin our balancing act.

We now need to consider the other factors that will affect our gas choice. First of all is logistics. What gasses are actually available? Many technical dive facilities have their decompression gasses pre-mixed, so you may be limited to what they have available or are willing to blend (gas blending can be a time consuming process). Also, there are many places in the world where 100% oxygen is not available, or can only be filled to roughly 150 bar/ 2000psi, depending on the fill station’s equipment. Once you know what your options are, you need to look a bit closer at the environment you’ll be diving in and how you will conduct your last decompression stop.

Many divers will vary the depth they plan to conduct their final decompression stop based on the environment they will be diving in. In a perfect world, we would always conduct our last stop at 3 metres/10 feet. Unfortunately, this is not a perfect world. Rough seas and overhead environments may make it difficult or impossible to conduct your last stop at 10 ft, so it may need to be conducted a bit deeper at 6 metres/20 feet. Conducting this last stop on 100% oxygen could now be problematic as you will be exposed to a much higher partial pressure of oxygen for the duration of the final decompression stop. Add rough seas to this in open water, and it could be very difficult to remain at a safe depth on oxygen. This is an instance where reducing the oxygen content may be wise. While a lower fraction of oxygen will not be quite as effective as a decompression gas on this final stop, it can significantly reduce the diver’s oxygen exposure. If you are making multiple gas switches in order to maximize the partial pressure gradient for the entire ascent, you will also need to look at the environment to decide what gasses to carry. A good example of this would be a cave dive. If you were planning your dive to switch to 50% at 21 metres/70 feet, but you know that there is a restriction in the cave at 21 metres/70 feet making it difficult to conduct a proper gas switch, you have a few options. First, would be carry the same gas, but decide to switch to it at a shallower depth where there is not a restriction. This would work fine, but would not be as effective for your decompression. You could also choose to bring a different decompression gas. A leaner nitrox mix could be switched to a bit deeper, but would not be as effective for the shallower stops. A richer nitrox mix would be more effective in the shallower stops, but you would not be getting the advantages of a decompression gas until later in the decompression schedule. Using desktop/mobile decompression software makes running these alternative options quick and easy so you can see immediately how your choice will affect your decompression plan.

After looking at all of the scenarios above, sometimes it just comes down to personal/team preference. Many divers and dive teams choose to use a standardized set of decompression gasses. This policy helps keep things simple and consistent. If a diver always carries 50% and oxygen for decompression, then they are always making gas switches at 21 metres/ 70 feet and 6 metres/20 feet. This standardized method streamlines the dive planning considerably, is consistent, and works well for many applications.

While this is not a complete discussion on decompression gas planning, it’s a good example as to what type of considerations we need to take into account when choosing our deco gasses. These points, along with others, are covered in depth in the TDI Decompression Procedures, Extended Range, Trimix, and Advanced Trimix courses and course materials. For more information on these courses, please visit TDI courses section

Remote Dive Site Decompression Illness – How to Save a Divers Life

Remote Dive Site Decompression Illness – How to Save a Divers Life

by Bret Gilliam
diver climbing ladder

As secret agent James Bond once sagely observed to Q, who supplied his special equipment and was complaining that he was bringing it back damaged, “It’s hell out there in the field.”

Divers aren’t dealing with jet-packs, ejection seats in Aston-Martin sports cars, or the best way to use the strangling wire released from the stem of a Rolex. But it can get a bit dicey in the field for us as well. I’m talking about the hard and grim reality of dealing with medical injuries in the middle of nowhere when facilities are not available and evacuation is not an option. If you are on a live-aboard, expedition vessel, or remote island when emergencies arise, you will have to be prepared to deal with them on-site and with the equipment on hand.

There are scores of scenarios that may present, from tropical viruses and severe stinging organisms, to lethal bites from sea snakes. But the most prevalent danger over the years has been decompression illness (DCI). If you pick up just about any diving text, medical reference, or even read DAN’s protocol for what to do when DCI manifests in a diver, the first directive will be to administer 100% oxygen by demand mask and transport the patient to a recompression chamber. Great advice. Good luck if you happen to be anchored in Chatham Bay at Cocos Island… 380 miles offshore. In Costa Rica there are no helicopters or seaplanes that can travel the distance, let alone do it round-trip, without refueling. And there is no fuel on Cocos Island. No Starbucks either, for that matter. The same is true in the Komodo Islands, Raja Ampat, or the Banda Sea in Indonesia. Think you can get to a chamber in the Solomon Islands? Oh yeah, it’s right next to the IMAX theater on Guadalcanal.

Reality is a bitch. If you or a member of your team gets bent in a remote area you will have to deal with the treatment yourself. This not only takes special training, it requires onboard-specific special equipment and trained support staff. A couple of D-cylinders in your nice little oxygen case aren’t going to get the job done.

Let’s take a quick review of DCI and what must take place to get a satisfactory outcome. First and foremost, you need oxygen. And lots of it. Secondly, you need pressure. That what’s going to crush the inert gas bubbles and let them be absorbed back into blood and tissue without occlusions and permanent physiological deficits. Time is the critical issue: the window for the most effective treatment is about one hour from the first presentation of symptoms. Tick, tock…

It must be ingrained in divers to recognize and report DCI symptoms as early as possible. Unless you are dealing with extreme exposures and incomplete decompression, symptoms will usually not present while the diver is still underwater. But upon surfacing the clock is running. This article does not have the space for a treatise on symptomatology but DCI will present as pain in the limbs or joints, or as more subtle neurological deficits initially; but central nervous system (CNS) issues will progress and can include paralysis.

Many texts distinguish DCI symptomatology into Type I (pain only) or Type II (serious symptoms, CNS involvement). To the layman or diver in the field, this distinction is not of great importance and requires special training in many instances to classify presentations. Most importantly, we want our readers to be able to recognize any symptoms or signs of DCI quickly and take immediate action.

At the first sign or symptom, the patient should immediately be placed on 100% oxygen… via demand mask. Don’t waste your time even putting a free flow mask in your gear package. You need to get the patient oxygenated. Free flow masks are wasteful of the gas, inefficient in their delivery, and you only have so much inventory of oxygen available. The therapeutic effects of 100% oxygen to a DCI victim cannot be overstated. In a significant number of cases, immediate oxygen breathing will arrest symptom progression and achieve relief without the need for recompression. But the key word here is “immediate”. Every minute lost allows for more inert gas bubbles to form and aggregate. By flooding the victim with 100% oxygen and eliminating any further intake of nitrogen from atmospheric air, you are creating a gradient for bubble size reduction and elimination. Cross your fingers and hope the victim begins recovery. You should be trained in field neurological exams and go through the checklist as soon as the diver suggests they may have DCI. Do a re-exam after the first hour of O2 breathing. If the patient’s symptoms have stabilized or improved, continue O2 administration with hourly reassessments. If you’re lucky, they may have dodged a bullet.

But you have to have an available inventory of oxygen onboard. I recommend a minimum of three H cylinders and a transfer method to the smaller cylinders commonly used with DAN O2 kits and to O2-cleaned scuba tanks because you’re going to need a lot of gas. If you’re getting results with demand mask oxygen, continue the patient’s breathing for two hours, then a 10-15 minute air break, then back on for two more hours. Follow this regimen for 12 hours and then make a complete assessment. If the patient is symptom-free, it’s probably okay to take them off O2 and confine them to a bunk for another 12 hours or so. Check urine output as well for volume and color. Cease all diving activity for 72 hours, or completely, unless they have a specific skill necessary to the project.

Now comes the tricky part: if the victim does not get better within the first hour on oxygen they probably need to be recompressed. The only way to do this is to get them in the water. This requires an in-water oxygen delivery system. Ideally, there should be an oxygen clean full-face mask available but an oxygen clean scuba regulator will do. (Full-face masks are preferred since the patient is less likely to lose their airway in the event that an oxygen induced convulsion event occurs.) Obviously, it is not desirable to attempt to place an unconscious unresponsive patient underwater. But as long as they can breathe on their own, I’d even risk this since the alternative is so dire.

In-water recompression has been around for five decades but it requires very specific training and equipment. You cannot attempt such a treatment without training. There are a variety of treatment tables that work extremely well. Some have evolved over years of experimentation and commence at shallower depths than conventional tables used in dry chambers. Other experienced contingency experts like to proceed with Table 5 that begins with a direct descent to 60 feet. But all this is predicated on oxygen supply, an oxygen clean delivery system, a conscious patient that is aware of what is happening, and several divers to rotate as underwater tenders with the patient. Most treatments will run two hours or more.

Ideally, a surface supply hose system to the patient is safest and most efficient. Air breaks also have to be factored in since a patient cannot breathe oxygen exclusively at depth. So the supply system underwater must allow for gas switches either from the surface supply hose or by changing scuba cylinders underwater.

You’re going to be underwater for a while. Proper thermal insulation for the patient is necessary as well as a fresh water hydration delivery bag or bottle. Most DCI cases manifest toward the end of the diving day and so it’s likely that a good portion of the treatment will be conducted in the dark… after sundown. Lights need to be available and the tender may also have to deal with patient anxiety. You also need to be prepared for marine life encounters. It’s unlikely that a shark will decide to chow down but the presence of predators is also a reality and the team should be prepared to ward off aggressive threats.

It all sounds more than a bit daunting. And it should. But the alternative is almost certain serious physiological damage including paralysis and death. You have to plan well in advance to have the necessary support equipment onboard and this is not easy in most third world countries. First and foremost, you have to have enough oxygen and the average live-aboard barely carries enough O2 for more than about a four-hour surface breathing period. If the operator cannot provide the other breathing delivery equipment, you may have to bring it with you. For the vessel operators that I provide operations consulting to, I recommend that they be fully prepared with all gear and staff trained to do the treatments if necessary. But these operators are few and far between. Do your advance due diligence, get proper training in field treatment contingencies, and expect to be called on to perform.

Remember: Evacuation is not an option. Without sufficient oxygen the patient has no chance. And if they don’t respond to surface oxygen breathing, there is no choice but to proceed with in-water protocols since you have to get the hyperbaric effect of pressure for inert gas bubble compression.

That’s the straight talk. Now you decide to what level you want to be prepared. There are no short cuts. TDI Headquarters can refer you to proper training professionals. This is not a dumbed-down meaningless dive specialty card. This is dead serious. I intend no pun with that last sentence…

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Bret Gilliam is the founder of TDI, SDI and ERDI. He is credentialed as a Recompression Chamber Supervisor and an Instructor Trainer for Diving Medical Technicians and Physicians. He has been widely published on diving emergency medical procedures including in-water recompression. Professionally diving since 1971, he authored the diving medicine section of the reference text “Pre-Hospital Trauma Life Support” and has treated or consulted on over 200 diver treatments in his career.

Nitrox – When to Dive It

by Cris Merz:

Nitrox Diver

The fantastic stories about voodoo gas seem to have mellowed out a little in the last 20 years. From, “It’ll kill you” to “You will have soooo much energy after the dive”, it never ceases to amaze how nitrox, as a topic for discussion, has always been a leader in misconceptions.

With many reasons in favor of diving nitrox, the reasons for doing so may hold a little more scientific value today than they did 20 years ago.

Few advances in the realm of diving have had a more profound impact during the past two decades than the widespread availability of Enriched Air Nitrox. And nothing has made the switch from diving air to diving nitrox more straightforward or more enjoyable than nitrox programmable dive computers.

Simply put, nitrox – air with additional oxygen content – allows divers to enjoy longer bottom times (and shorter surface intervals) than their air-breathing dive buddies, while staying within the limits that were stressed in their open water training.

Nitrox makes this possible because it contains reduced levels of nitrogen compared to air and less nitrogen translates into more bottom time! But of course there is a price to pay. Diving nitrox does present risks that are not present while diving air and these risks require divers to take additional steps during their pre-dive planning and then adhere to that dive plan.

The number one reason for diving nitrox is safety. When diving with a greater amount of oxygen (32% or 36%) in the mix, rather than air (21%), you decrease the risk of decompression sickness because you’ve lowered the amount of nitrogen you are breathing in at depth – and as we know, nitrogen is the number one culprit associated with decompression sickness.

When should we dive nitrox? Well, whenever the opportunity presents itself. It may not make a great difference but it certainly will not hurt. Unless you go diving beyond the Maximum Operating Depth (MOD) of the mix in your tank, it is beneficial to you every time, though sometimes those benefits are much greater than others based on your diving profile.

The moments when nitrox will make the greatest difference is when you are doing multiple dives over multiple days and are getting close to some of the no-decompression limits your personal dive computer is telling you about.

As stated, when you dive using nitrox you can take advantage of increasing your maximum allowable bottom time. This happens because the extra oxygen added to your breathing gas when it was filled has displaced nitrogen. Because there is less nitrogen in the mix to be absorbed by your body you can spend longer at depth before you reach the nitrogen limit – which is the decompression limit. Secondly, since you are absorbing less nitrogen on a given dive, your surface intervals can usually be shortened.

Being on a live-aboard, hundreds of miles from home where you are doing 3 to 4 dives a day will allow you to see a huge difference if you can compare yourself to those diving on regular air. You have paid a lot of money to get there and you want to make each and every dive count. You do not want to get back in the water for the fourth dive so you can zip about at 50ft/15 meters just because you have reached your no-deco limits for the day – especially when the schooling hammerheads are hanging out around 70ft/21 meters. That is where you want to be… for as long as possible.

Despite having depth limits to be aware of due to the risk of oxygen toxicity, and perhaps some additional costs for the fills, the benefits of nitrox will play a role in your steps to keeping your dives within safer limits than if you were on air.

If you are not yet nitrox certified, find out more about diving with enriched air from your local SDI or TDI instructor.

You will discover that diving nitrox is not rocket science. The concepts are straightforward and easy to understand. Of course, like most things relating to diving, the subject does have another side and if the science and technology behind the basic concepts of nitrox interest you or if you find yourself wondering how nitrox with higher levels of oxygen than 40 percent would affect your diving, you may want to consider continuing on to Technical Diving International’s (TDI’s) Advanced Nitrox Diver course.

How To: Label Your Nitrox Tank

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.