Nitrox Enriched Air And The Magic Circle

has gone guys ass browning in from Lake kickers giving Rita today's video is going to be really neat I'm going to show you something that we call the Magic Circle now I'm gonna show you how it works now this applies to nitrox divers all the way up to the technical level and if you've taken a nitrox recently say within the last few years you probably had an instructor who said hey if he ain't got a computer you can't dial nitrox and that's simply not the case but the reason that the industry tends to go that way is because using a computer doesn't make things a whole lot safer a whole lot more convenient and just plain more fun for you as the diver so Dobbin what the computer is definitely a way to go but I'm going to show you some cool little tips and tricks that you can do anytime that let's say that you don't have a computer maybe you have went somewhere and you're written a set of dive gauges a watch whatever that it is maybe you're renting and you don't have a computer use but you are not truck certified and you do want to get nitrox let me show you what's called the Magic Circle and just how easy it is to do now before we get started we use the Magic Circle for several different things such as our maximum operating depth knowing how deep we can go on a certain blend of nitrox is very key to our safety also the best mixture maybe we've already predetermined our depth we're going to dive a shipwreck and we want to know what the best mixture for nitrox it is to die about and of course our oxygen dose we need to know how much partial pressure of o2 we're collecting at the end of that dive so that we do not exceed our partial pressure now there's two that we work with 1.4 and 1.6 1.6 of course being our contingency or our absolute workload of partial pressure of o2 we're simply going to base everything we do today off the the 1.4 PPO - because we never want to exceed that so I'm go ahead and I'm gonna take my magic circle at top and all I've done is simply drew a circle put a tee in it at the top I'm going to put 1.4 and I'm not going to change that that 1.4 is simply the partial pressure of o2 do not want it seen throughout my dies on the left side and on the right side is going to be two other numbers this left side will always be my nan trucks blend okay so I'm going to start with the basic no.1 nitrox which is 32% so we'll simply right point three two in this side now this first calculation that we're going to do is simply our maximum operating depth how deep can I go simply using any say particular blend out there and we're going to use no.1 or 32% now when we do calculations the only rule that we need to remember any two numbers will give me a third number so if I've got the two bottom numbers I can get the top number if I got the top and right number I can get the left number if I got the top and left number I can get the right number now the key here is is understanding what math to do add subtract multiply divide it's real simple if I'm working top to bottom I'm going to simply do division if I'm working side to side I'm going to simply use multiplication and it's real simple if you pull out your calculator here to follow along with me it makes a lot easier than doing long multiplication alone division so working off a 32% blend and not exceeding a one point four PPO to I need to know what is the maximum operating depth I can go to it's real simple guys you simply take one point four you divide it by 0.32 and that's going to give you an answer of four point three seven five everybody's going to look at that and say four feet almost five feet no that can't be right it's simple guys this is our absolute atmospheric pressure we need to convert that back into depth and it's real simple to do once again I'll have all these equations in the description below and I'll even have the conversion to go from depth to atmospheric pressure and atmospheric pressure back to death to do this all I got to do is simply minus one which would be the atmospheric pressure so that would be four point three seven five the minus one would be three point three seven five and simply times it by 33 and that's going to give me a depth of a hundred and eleven feet and what the magic circle says is to determine maximum operating depth I take my partial pressure of o2 which is 1.4 I divide it by the blend that I'm using 32% and it gives me my maximum operating depth of a hundred and eleven feet you can do this with any blend we're going to do a second Lind which we're going to use Noah two or 36% let me get this erased here for you and I simply do the same calculation I'm going to take 1.4 I'm going to divide it by 0.36 and that's going to give me a answer of three point eight eight eight once again that three point eight eight eight is my absolute atmospheric pressure is all that is to convert that back into depth it's real simple a minus one from it which would give me two point eight eight eight times that by thirty three and it's going to give me a maximum operating depth of ninety five feet all right so basically using thirty six percent not exceeding a one point four partial pressure of o2 I can dive down to 95 feet and that's all I have to do for this maximum operating depth equation and using the magic circle and placing it on the board here makes it very easy you can see it you can do the calculation and it's not no rocket science to it if you will it's just basic addition subtraction multiplication division makes things very simple for us let's take this a little bit further and let's say that we have already predetermined our depth let's say we're going to a depth of eighty feet and I do not want to exceed a one point four partial pressure of o2 and I need to know what's called my best mixture for that depth here's the formula for the best mixture once again it'll be listed down in description below and you know how we do it I simply take my depth I need to convert that to absolute atmospheric pressure it's real simple there's actually two equations you're going to add 33 divided 33 or divide 33 and add one to it it's the exact same formula both will be listed below it'll be a conversion to go from depth to absolute atmospheric pressure so simply take 88 or 80 feet add 33 to it divide 33 and I'm going to get an absolute atmospheric pressure of three point four two real basic real simple I'm still working top to bottom so my math here is going to be division I simply take one point four divided by three point four two and that's going to give me a mixture of 40% so the absolute best mixture at eighty feet not exceeding the one point four partial pressure of o2 is going to be forty percent nitrox once again you can do this at any depth recreational or technical level you can simply divide it out and it's going to give you your best mixture for that depth all right let's move on I'll show you one more real quick let's say that I have a depth of say sixty six feet I have a mixture of thirty two percent I need to be able to determine whether that is going to exceed my partial pressure of one point four it's real basic simple math guys all you got to do is simply multiply the two together and it's going to give you you take sixty six now we do need to convert that into absolute atmospheric pressure which would mean three atmospheres you take point three two you multiply it by three and that's going to give you a total of 0.9 six which is well under our partial or our maximum partial pressure at one point four so we're good and we're safe to dive with that blend at that depth so guys I hope the magic circle helped you out once again in the description you're going to have all these formulas can including your conversion for depth to absolute atmospheric pressure and then back from Avenue absolute atmospheric pressure back into death I hope you can use the magic circle in the future definitely dial computer guys it does make things simpler it does make things safer for us but in the event that you want to know what that computer is actually calculating for you these are the calculations that we use all the time so guys I appreciate you watching this video I hope the magic circle helps out for you as always make sure you follow us on Instagram and Twitter make sure you like us on Facebook penicillin subscribe to us here on YouTube and as always guys we appreciate your business

Channel: LakeHickoryScuba

Views: 40,225

Rating: 4.9204969 out of 5

Keywords: Lake, Hickory, Scuba, Marina, Taylorsville, North, Carolina, Alexander, County, Diving, Drysuit, Wetsuit, BCD, Regulator, Fins, Mask, Snorkel, Public, Safety, Under, Water, Criminal, Investigations, Mares, OS, Systems, Ocean, Reef, Full, Face, Training, XS, Trident, Charter, PDIC, PADI, SEI, CMAS, Educators, International, Boating, Bait, Fishing, Docks, Search, Recovery, Specialty, Night, Drift, EFR, First, Aid, CPR, AED, Emergency, Oxygen, Provider, Divemaster, Assistant, Instructor, Trainer, Board, Discussion, SSI, School, Commentary, Nitrox, Magic, Circle

Id: Ho3erOkNEXQ

Length: 8min 56sec (536 seconds)

Published: Thu Aug 11 2016