It is a dry course so ideal to complete whilst planning for the 2020 Dive Season... Next course Saturday 11th January and there are spaces.
Find out more about Enriched Air (Nitrox) by reading our web article and come and join us on one of our regularly running courses so that you can take advantage of the benefits of using.
It is a dry course so ideal to complete whilst planning for the 2020 Dive Season... Next course Saturday 11th January and there are spaces.
In June, a rash made me question a change in pool chemicals. The rash started Saturday after the pool session. When we heard back that there were no issues, Tracey suggested I contact Midlands Diving Chamber (MDC) for advice, probably because she was considering the dives Sunday (30m, 24m, and 7m) , but in my mind it was from the pool, it had to be right, that is when the rash started!
Sunday after the dives, I went home and was quite tired so went to sleep very early, not abnormal when I have had a high nitrogen load, also it is exam season and I am a teacher so that was fine.
On my arrival at MDC dive history was discussed, and the profiles were examined. The shallow dive had a few blips, but any shallow dive will have spikes, it’s the nature of a shallow dive.
The doctor was not convinced of DCI, but did a physical. Nothing significant until the neuro exam, which showed a decrease since my last medical, that he completed two months prior. I went in the chamber, better safe than sorry.
After treatment using RNT 62
I was re-examined and sent home, with the doc still unconvinced, ‘you could have just been tired this morning’. I was sent with orders to phone in the morning and stay out of the water for ‘a few weeks’ because it is the height of the season and he didn’t want to limit my diving time. Thursday I had a headache and some dizziness later in the day, so I chose to attend a retreatment USING RNT 66 just in case, even if it put me out of the water.
If I did have a bend, the only reason that it was caught was because I made the decision to go to MDC for my yearly medical. There was no other reason that put me in the chamber than the doc knowing my neuro assessment was weaker. Oddly, all because I had a rash that may not have been related. I did learn that 10% of reported bends are in shallower than 10m and instructors in that category are often from pool work. When asking about returning to diving, the doc gave me a timeline and I asked if that included pool work. He stated the pressure changes in the pool are MOST significant and categorically could not go in the pool until my fit to dive medical. How many people think ‘its just the pool’?
This meant there was a huge learning curve. I talked the theory to death with Charlie. He reminded me every step of the way that its all a theory. Tracey reminded me that there was nothing I could have done to change what happened, it was a typical training profile we do and one we have done many times before!
Every step of the way I had a full team behind my recovery. I am fit to dive not just physically, but mentally because I have taken this as a development point and continue to research decompression, making me a safer diver.
What we here at Dive Rutland have 'learnt' from this experience is that undertaking our yearly Health and Safety Dive Professional medicals with our local chamber - Midlands Dive Chamber (MDC) at Rugby means they have our medical files and a baseline to compare to in a scenario such as this. We feel that as Bridget had her files at MDC the neuro check being weaker raised a flag and although treatment potentially not required a 'better safe than sorry' approach was undertaken, which we applaud MDC for.
Its also important that if anyone does not 'feel right' after diving be that in the pool or open water it is raised with a member of the team, so we can discuss and guide.. But at the end of the day MDC are on call 24 x 7 and always happy to take that call. There are cards in the shop that you can put in your purse or wallet, so no excuse not to have the number handy.
And most importantly remember your treatment is free and provided by the National Health Service, so a service as divers we should fight to protect.
Have a read of our new web page that has just been published called Equipment Care - Post Dive Regulator.
It was originally released as a blog entry in September of 2017, but we are continuing to see regulators coming in for service with 'foreign objects' inside them, so we thought we would now formalise that blog and continue to write some 'care' articles for each piece of diving equipment.
We hope you find them of interest, but if you want to know more about how to care for your equipment then why not join us on our next Equipment Speciality Course
Although Nitrox has been used for recreational diving for almost 25 years, it is still often misunderstood.
As an instructor, I have found myself correcting countless students and divers who are under the impression that Enriched Air Nitrox (EANx) diving enables a diver to dive deeper than with normal air. This is a common misconception about nitrox diving.
I hope that this blog will help to make sense of what it is and what it can do for you, but remember you do need specific training before diving using Enriched Air for the first time.
What is Enriched Air diving?
Already the words Nitrox and Enriched Air have been interchanged in this blog entry. That is because Nitrox quite literally refers to a mix of nitrogen and oxygen, regardless of the percentage of each in the mix, which could be means air could be called nitrox (21% Oxygen, 79% Nitrogen).
We should properly call the nitrox we use while diving “enriched air nitrox". It refers to any blend of nitrogen and oxygen in which the oxygen concentration is greater than that of normal air. This means an oxygen level of 22 percent or higher, although the most common enriched-air nitrox blend is 32 percent. The recreational diving limit is 40 percent oxygen.
What does it do?
As every entry level diver knows, increased pressure at depth causes our bodies to dissolve the nitrogen in the air we breathe into our bloodstream. This nitrogen absorption limits the time that we can spend underwater. As we dive deeper and for longer, we absorb more nitrogen at a greater rate. Our no decompression limit correlates to the amount of nitrogen our bodies can absorb before we must perform compulsory decompression stops or suffer the consequences of decompression sickness.
Enriched air nitrox slows down the nitrogen dissolution rate in our bloodstream, because there is less nitrogen in the mix that we’re breathing. The higher the percentage of your enriched air blend, the more extra oxygen will replace nitrogen.
Benefits of Enriched Air Nitrox Diving(EAN)
Divers use enriched air nitrox for several reasons. An increased no decompression limit means longer bottom times. The lower percentage of nitrogen in the nitrox you’re breathing means your bloodstream is also absorbing nitrogen more slowly.
EAN is best applied to shallower dives. As an example of the improved bottom time one may realise by using EAN is for a diver making a dive to 18 metres on air has a no decompression limit of 56 minutes. In contrast, a diver making the same dive on Nitrox containing 36% oxygen would have a no decompression limit of 125 minutes. That's an hour more bottom time! (Results based on the PADI Recreational Dive Planner)
Surface intervals are usually shorter on nitrox as well. Since there is less nitrogen to off-gas, a diver on enriched air will be able to re-enter the water sooner than a diver using normal air after completing the same profile. This also means that divers using enriched air typically have longer maximum bottom times on repetitive dives.
Enriched air divers are often less tired at the end of the day as well because of less off-gassing.
Enriched air can be a valuable safety buffer for divers who choose to use it while following normal air tables, computers, profiles and procedures. Doing so creates a considerable conservative margin that further reduces the risk of decompression sickness.
Anyone who may be susceptible to DCS, such as those who are tired, overweight, older, have suffered decompression sickness before, or are diving with injuries, should consider diving Enriched air
Myths, considerations and dangers
Although the benefits of diving with enriched air are significant, doing so also involves certain risks. One of the most common misconceptions about enriched air nitrox is that users can dive deeper than with normal air; in fact the opposite is true.
Under pressure, oxygen becomes toxic. The percentage of oxygen in normal air (21 percent) only becomes toxic at depths greater than the recreational limit. But the increased percentages of oxygen in enriched air mean that toxicity can become a problem at much shallower depths.
Toxicity causes convulsions that put a diver at risk of losing his regulator and subsequently drowning. However, enriched air courses teach divers how to work out their maximum operating depth using the percentage and partial pressure of the oxygen in their mix.
As long as you adhere to the maximum operating depth, oxygen toxicity should not be a problem.
Although it is safe to use standard scuba equipment with air blends containing up to 40 percent oxygen, the process by which an enriched air cylinder is filled often involves much higher concentrations.
Partial pressure blending exposes the cylinder to pure oxygen that techs later dilute with normal air. If they are not treated for exposure to such high levels of oxygen, cylinders can explode. Therefore, any part of the cylinder that comes in to contact with pure oxygen needs to be “oxygen clean.” You cannot interchange cylinders used for enriched air and normal air. Enriched air cylinders require decals or stickers to differentiate them from normal ones; service them annually.
There are a few other equipment considerations to bear in mind when thinking about enriched air diving. Before each dive, you are personally responsible for checking the percentage of oxygen in your cylinder. If it is even slightly off, your maximum operating depth (MOD) calculations will be too. You will need an analyser to check. Although you can usually borrow one from your dive center, it’s a good idea to have your own if you intend to dive nitrox regularly.
If you dive with a computer, you need to make sure that yours has enriched air settings. It must correlate to the details of your mix before beginning each dive. Remember that enriched air does not improve air consumption, and neither does it give immunity to decompression sickness.
Continue to check your gauges, depth and time limits as often as you would when diving on normal air.
With these precautions and the necessary training, nitrox diving is a fantastic way to get the most out of your diving experience. You’ll spend more time in the water, and less time waiting to get back in.
Should I do the Enriched Air Speciality?
Curiosity and a thirst for adventure is why many of us become divers in the first place. But we aren’t going to take the plunge with just anyone so why should new divers.
So to all those potential new divers or even those qualified who are looking around at courses and Dive Centres have a look at our article How to Choose a Dive Centre. Then pop in have a chat, maybe a cup of tea or coffee and if you like what you see, learn to dive with us here at Dive Rutland or join our club everyone is welcome.
The air and water temperatures are dropping and already we have started to see other people with Regulator Free flows at some of the open water sites we use...
We wrote an article last year for our club members as part of our monthly newsletter on Regulator Free Flows... its now been updated and published on our website for all.
I have been meaning to write something like this for a well now and every time I service a regulator that has 'issues' it reminds me that I have not done so... so after a particularly 'interesting service', I thought it was finally time to get it done.
I often ask myself, why divers invest a significant amount of money in dive gear and then use and abuse it! Remember if you look after your equipment it prolongs the life of it and more importantly reduces the chances of it failing on you. This is particularly important where your regulator is concerned. IT IS YOUR LIFE SUPPORT SYSTEM underwater after all.
Do not drag it along the ground - sounds obvious does it not?
Before you get to the cleaning stage, when getting in and out of the water, ensure your equipment is not dangling and being dragged along the ground, particularly if sandy or on a pebbly beach
The following pictures show you what happens when a service technician is servicing a regulator that this has happened to... it made a real mess all over my service bench....
Clean Your Regulator after use
As you probably guessed, your regulator should be thoroughly rinsed off using fresh water after your day of scuba diving is complete.
Just be certain that you don't get any water into the gear's first stage. The internal parts are vulnerable to damage when they're exposed to water and moisture, so letting them get soaked will probably end up causing you to have to take your regulator to a professional to get fixed.
Prior to rinsing off your regulator, replace the dust cap, securely fastening it on. Of course, make sure the cap is dry first. Use compressed air that you could get from the cylinder in order to shoot excess moisture out of the dust cap prior to fastening it into place.
Rather than putting the first stage in fresh water to let it soak, just rinse it off completely in the sink. This will prevent water from seeping past its dust cap. Or you can instead completely submerge the regulator with the first stage attached to a pressurized cylinder. This will also prevent water from entering the unit.
Avoid pressing the purge button on the primary second stage or the octopus during the process of washing the regulator. This will let water into the first stage, which you don't want.
And if you do have hose protectors, be certain you thoroughly rinse beneath them throughout the cleaning process.
Move the low-pressure inflator connector in an effort to get rid of grit, salt, and sand to prevent corrosion and keep the unit performing at its best.
Once you're all done rinsing off the regulator, it's best to allow the unit to dry off completely by hanging it up in a safe place. Then simply store it away accordingly.
Have your regulator serviced according to the manufacturers recommendations or if you have stored it away and not used recently. Basically never dive on your regulator if you don’t trust it to perform flawlessly, even in an unanticipated out-of-air emergency where a much greater demand is placed on it.
If in doubt, have it serviced.