What is the Benefit of Diving with Nitrox?
Every certified diver knows there are limits to the time you can spend underwater. Air supply is the most obvious one.
However, there is also a second limit you have to take into consideration when planning your dives – Nitrogen absorption.
How long you can dive with Nitrox
We can extend our bottom time by using higher amounts of oxygen and lower amounts of nitrogen.
Divers can then lengthen their No Stop Times, shorten surface intervals and achieve a greater buffer for decompression safety in certain diving conditions.
While Nitrox diving has been used in recreational diving for over 25 years, there is still a degree of mystery about it.
Even some misunderstanding what it can do for your diving. Because of this, many divers never take the short and fun course that expands their limits.
Once you have trained for this scuba diving with Nitrox, it only involves verifying the percentage before each dive.
The Facts about Diving with Nitrox
It’s very important for all divers to understand the deeper you go, the faster your body absorbs nitrogen.
As taught on the PADI Open Water course, decompression sickness occurs due to nitrogen absorption into our bodies when diving.
This is from the nitrogen in the air you breathe that dissolves in your bloodstream as you dive deeper into the water and as the pressure also increases.
As student divers learn during the PADI Open Water diver course this is due to the increased density of gas at depth. This is also why we plan our dives using dive tables and more specifically on dive computers.
Performing Proper Decompression Stops
We need to allow the nitrogen to escape from our bodies by performing decompression stops (the time the body will take to expel the absorbed nitrogen).
If we allow the nitrogen to build up in our system and resurface too quickly without performing decompression stops, you may experience decompression sickness.
Symptoms include joint pain, dizziness and extreme fatigue, and can result in mild numbness of the limbs, paralysis and in rare cases death.
Recreational Divers and Decompression Limits
As recreational divers we are always completing ‘no stop’ dives. What this means is, at any time during the dive, we can directly ascend to the surface no faster than 18m per minute or what our computer specifies without having to perform a stop.
There is no need to make staged decompression stops on our way up.
We can however extend our no stop limits by using Nitrox instead of regular gas.
This helps by increasing our allowed diving time as it offers less nitrogen (and more oxygen) for us to inhale, reducing the amount of nitrogen that will quickly be absorbed into our bodies and in doing so lengthen our no-stop limits.
Additionally, this gas mixture doesn’t necessarily allow you to dive deeper since the increase in oxygen equates to a shallower maximum operating depth (MOD) for our tank.
Scuba Diving with Enriched Air Nitrox
As an Open Water diver I wanted to extend my bottom time as I have great air consumption and was tired of ending dives prematurely due to my no stop limits.
I commented this to my dive buddy one afternoon and my Instructor who had recently certified me as a PADI Advanced Open Water introduced me to “Enriched Air Nitrox“.
The course itself was fantastic fun and covered the understanding and use of:
- Managing oxygen exposure
- Analysing tank content
- Enriched air tables
- Enriched air compatible equipment
- Equipment markings
- Tank filling
- How to use your dive computer for diving with Nitrox
Nitrox must be analysed using a Nitrox analyser before you use it, which you can typically borrow at the dive center.
It is your responsibility to analyse your blend and to enter it into an acceptance log. During the Nitrox course, you will learn how to do this.
Today most of us divers use dive computers and my instructor showed me how to get the most out of mine by helping me adjust the settings for Nitrox diving.
How to Use Nitrox Dive Tables
However, computers can fail and it is prudent to have a backup plan to help you continue with your dive and remain safe. This is where dive tables come in.
Dive tables are easy to follow for both single and repetitive dives. They are typically made of waterproof plastic so you can bring them with you for easy reference underwater.
Core learning objectives that are part of the Enriched Air Nitrox course are not just about contributing to longer bottom times during no decompression diving.
We learned about the safety aspect too and that oxygen exposure can also be harmful to the body.
This is called oxygen toxicity, with high concentrations of oxygen that could in unlikely situations lead to seizures, unconsciousness, difficulty in breathing, lung damage, eye damage, and even death.
Additionally, Nitrox contains a larger percentage of the highly flammable oxygen, its tanks and valves must also be handled properly and cleaned with care to avoid unintended explosions.
This is why the training that is provided in the Enriched Air Nitrox course is necessary to make us all better divers and keep both ourselves and our buddies safe.
The dives we undertook we use a blend of 32% and 36% oxygen. Below is a graphic to demonstrate how the mixtures where used according to normal air.
Normal Air – Oxygen (21%) / Nitrogen (79%)
Nitrox 32 – Oxygen (32%) / Nitrogen (68%)
Nitrox 36 – Oxygen (36%) / Nitrogen (64%)
Increase Your Bottom Time with Enriched Air Nitrox
So what is the primary benefit of using Enriched air during your dives? As you can see on the chart, during your dives you’ll be exposed to less Nitrogen.
This results in longer No Stop Times compared to dives planned and conducted on normal Air.
The bottom line is, Nitrox diving is not any less dangerous than diving with regular gas.
Nonetheless, it should be done correctly. With the proper training (Nitrox Certification) and proper adherence to guidelines, risks can be decreased and divers can enjoy a whole new level of scuba diving.
Teaching Nitrox Specialty Dives
My student had amazingly good air consumption on the Open Water training dives. Highlighting this, and having made me aware he was interested in completing more PADI courses I talked him through the benefits of using Nitrox.
Understanding the benefits, he opted to add the PADI Enriched Air Specialty course to the PADI Advanced Open water diver course he had already signed up for.
Selecting a ‘combo deal‘, the student supersized the PADI Advanced Open Water course with the PADI Nitrox course, earning two PADI certifications and making some savings along the way.
The student then convinced his girlfriend to sign up for the Advanced / Nitrox combo too. Both students had clearly been bitten by the diving bug.
They admitted to me they were addicted and wanted to learn as much as possible during their stay on Koh Phangan
Explore More of the Dive Sites
Amazing! No other divers, just us. At this point we were able to see the wreck in all its glory. All resident marine life came out to play. We were on our own, just the three of us surrounded by nature.
It was really enjoyable roaming around the wreck with just my students, and no other divers on site.
The visibility during this dive was probably the best I’ve seen on this wreck. During our safety stop we could still see the whole ship. From the front cannon all the way to the back cannon. That is when the camera’s came out to take some shots from this extraordinary sight.
Enriched Air PADI Certification
Having already completed the Underwater Navigation, Peak Performance Buoyancy & Night Adventure dives the previous day we returned to land, and I certified both of my students as PADI Advanced Open water divers and PADI Enriched Air divers.