Calculating The Equivalent Air Depth

Calculating The Equivalent Air Depth
Dive Computers not only make diving easier and safer, but they make planning dives a breeze. When you dive Nitrox without a computer though, and you are using a mixture of anything other than NOAA 1 (32%) or NOAA 2 (36%), you will need to be able to calculate the equivalent air depth for the depth you are going to, based off a 21% mixture. In this video, we show you how to using the EAD formula.
/ lakehickoryscuba
Lake Hickory Scuba Center & Marina
/ lakehickoryscuba
www.lakehickory...
/ lakehickoryscuba
/ lhscuba
/ lhscubamarina
Instagram - Lake Hickory Scuba
[e-mail]
420 Taylorsville Beach Ct. Taylorsville, NC 28681
828-632-7649

[@Cheetah223]

Thank you for the videos! This video and your "magic circle" video leave me feeling far more educated than the eLearning portion of my EANx class did. Great job explaining things clearly and simply.

[@LakeHickoryScuba]

You are very welcome Cheetah223, glad to know our videos are helpful and educational.

[@ThePriceIsRising]

Do you have any idea on how many people tried to explain this to me and it went over my head every time. The way you explained it, has me completely understanding it now. Thank you.

[@LakeHickoryScuba]

Glad you liked the video @ThePriceIsRising, and that you found it helpful.

[@kevintipene2287]

I’m learning and understand more from you than dive instructor. Especially the magic circle theory Thank you Brian 👌

[@LakeHickoryScuba]

Hello Kevin Tipene, glad you like our videos and find the helpful to you. Let us know if we can ever help you out.

[@ivoryjohnson4662]

My thoughts are with you and yours during this storm period

[@LakeHickoryScuba]

Thank You. We are at the base of the mountains, basically the foothills, so hopefully the wind won't be to bad. We are worried about the water and rain though.

[@culebrasnorkelwithlocals6182]

Dude you killed it! Thanks for that, i was stuck on stupid until heard you explain it.. God bless you!

[@LakeHickoryScuba]

You're welcome SCI Culebra Snorkel with Locals, glad you found the video helpful.

[@signalsoldier]

you Sir are a Gentlemen and a Scholar!

[@LakeHickoryScuba]

Thank You Signalsoldier.

[@jackjackattack9137]

Ran across this, this is good stuff !!!

[@LakeHickoryScuba]

Glad you liked the video jackjackattack.

[@richardskuta8165]

I’ve been watching the heck out of your videos they’re good where can I get one of those charts like you have at the end of this video

[@LakeHickoryScuba]

Hello RICHARD SKUTA, if you are referring to the SSI Dive Tables. There is a free download on the app store called, MY SSI. Once you have downloaded it, create you a free account, and you can find the tables under the tables section. Here is a quick link to help you register your free account. my.divessi.com/register

[@bb3438]

Well, I can no longer say that I won’t ever use algebra in life.

[@LakeHickoryScuba]

Very True.

[@zezo1389]

Hi Brian, your constant follower from Jeddah, Saudi Arabia and I am currently studying as a diving guide. Very nice explanation. A question arose when I watched the clip. I saw you round the number to decimal places. SSI table (we have the metric system). If there is no number in the calculations that matches the depth numbers in the table, do we jump to the higher number, or take the lower depth for safety precautions? . With thanks for your great effort

[@LakeHickoryScuba]

Hello Sniper Hunch, rounding up on the tables is ok to do, and this is what we teach our students to do. Even some computers will round up on the plan screen.

[@tanaasad2218]

Very Helpful!

[@LakeHickoryScuba]

Hello Tana, glad to know our video is helpful to you.

[@marinepilotchris3048]

Great video!! Does this work for metres or is there some other equation? I’m guessing the 33 in the equation is 33ft which equals 10 metres. So if I minus 10 instead of 33, is the equation still valid?

[@LakeHickoryScuba]

Hello Chris & Carolyn Case, you would be correct. To calculate in metric you simply use the incriments of 10 meters instead of 33 ft (sw) / 34 ft (fw).

[@marinepilotchris3048]

LakeHickoryScuba thanks so much!!!

[@LakeHickoryScuba]

You're welcome.

[@elikleine8996]

now can you make the same video using the metric system for european divers?

[@LakeHickoryScuba]

Hello eli klien, we will do our best to start integrating metric into our videos as well.

[@buzzmorse9879]

Brian Memorizing a formula is one thing-- but understanding it is another! It is clear that 80 feet is 80/33=2.4 ATM +1= 3.4 ATM total USING 40% O2-then ppO2= 0..4x 3.4= 1.36ATM and ppN2= 0.6 x 3.4= 2.04ATM FROM YOUR EXAMPLE 53 feet is the EAD? 53 feet is 53/33= 1.6 ATM +1=2.6 ATM TOTAL USING AIR 21%O2-then ppO2=0..21x2.6=0.546ATM and ppN2=0.79x2.6=2.1ATM SOOO- with 40% O2 EANx at 80 feet= ppN2= 2.04 ATM (see above) AND- at 53 feet- using AIR- -----ppN2=2.1 ATM I S THIS WHAT MAKES IT THE “EQIVALENT AIR DEPTH”-- the eqivalence of the pp of N2?? -------------- Your equation divides the “mix” N% by “air” %N=== this gives you a raw number that is essentially the less % of N - in your case- 0.6/0.79=0.76=== to me- showing your only using 76% of air nitrogen! Then you multiply that by “depth + 33”-- which to me is essentially the total ATM IN FEET? You then subtract 33 to just give water depth - essentially removing 1 ATM- of air? Soo-- I have no doubt that you are correct-- but what actually is being calculated on a deeper level- sure- it is easy to memorize formulas- but understanding why and what that formula means is much better! So- I ask- in simple words- WHAT DOES AND EAD ACTUALLY MEAN? Other definitions simply state it is ppN- at one depth versus another- please say in a simple way- Really enjoyed your lecture on EAD- memorized it- but still wondering about it!!! Buzz

[@LakeHickoryScuba]

Hello Buzz Morse, in short the EAD formula allows a diver to use standard air tables to calculate Nitrox dives. Basically, you can convert any Nitrox blend back into a standard Air Blend to calculate your no decompression limit. The SSI Air and Nitrox Tables, and most other agencies allow both the standard Air, 32%, and 36% tables to be used, but there are no tables for other mixes. Diving in 2022, all divers should be using a Dive Computer which eliminates the need for this calculation at the recreational level. Back in the early 1990's, Dive computers were not a necessity as they are today, so teaching the EAD was very important when diving Nitrox without a computer. Constantly calculating our Oxygen clock was also very important. Now days, dive computers do this for us, not to mention calculating our partial pressure of PPO2 at any given depth, and a plethora of other things.

[@nicolebradford9154]

I'm taking the Academic section of my nitrox class and the formula is different a I'm getting different numbers. Can you help me? [(1- fo2)(D+10) / 0.79)] - 10

[@nicolebradford9154]

Would.it be 58.35 if using the same D and blend? I think I caught what was different fo2 is oxygen while fn2 is nitrogen, correct?

[@LakeHickoryScuba]

Correct the FO2 stands for the fraction of oxygen, and the FN2 stands for the fraction of Nitrogen.

[@ozjohnno]

does the equation still work if you are using meters instead of feet?

[@LakeHickoryScuba]

Great question John. Simply by replacing the variable 33(fsw) with 10(msw), the equation would still work out.

[@Chogogo717]

Those SSI tables look better than the multiple PADI tables.

[@LakeHickoryScuba]

Hello Caleb Mcelhaney, we find that the SSI tables are very easy to read and helpful to all divers.

[@diversdown2116]

Love the math but i think u were a math teacher in a previous life

[@LakeHickoryScuba]

I’ve always loved math and science growing up.

[@alessioandreoli2145]

Nice video but feet really do not make sense in diving

[@LakeHickoryScuba]

Hello Alessio Andreoli thanks for the comment. Truth be told, it would be very difficult to use scuba fins if you didn't have feet. LOL