Dive decompression tank

Filling from what, high pressure gas banks, low pressure air compressors,medical oxygen supply for BIBS,helium make up??What are your hull penetrators does not your decomp chamber Mnf have recommendations??

Thanks for the info so far. I did not gave enough information and will try to correct this. Our Tank is Lloyds approved whit folowing data 50" horizontal single lock decompression chamber serial ss535 mk 51 working pressure 101.5 psi 70 msw testing 150 psi lloyds certification no. LIV 0733504/2.

We dive private (own company ) recreational and commercial (HSI). We use umbillical, scuba and rebreather systems and use air, nitrox and trimix gas. We blend all on site.

We have the folowing buffer tanks: HP air 500 L 300 ATM/BAR MP 2000 L 30 ATM/BAR and 250 L 6ATM/BAR. We have minimal 6 x 50L 200 ATM/BAR O2 and 3 x 50L 200ATA/BAR He.

Most dives 10 divers 50/Year = 500/Year are done in North Sea cold 0-14 celcius deep 30-90 meters Serious deco times (US navy tabels) low visability 0-5 Meters during last 10 years 2 deco accidents solved by 1 RAF and 2 German Navy.

We weld the Tank our self in the ship and have No experiance what so ever, so all help is more as welcome. We do not hope it is used, but be bought it as an extra safety.

Questions so far: 1) How fast do we have to bring the diver back to what pressure. 2) Vollume off Tank 4 m3 inlet to pressurise Tank 3/8" how much air can be inserted bij this inlet? 3) What stage is the best to fill It. (manufac. delivers the tank also in container with max compressor 500 L/M so to go to 20 meters MSL 4x2=8 m3 x2 = 16 minutes ?? Seems to me as unacceptable long. 4) what tabels are to be used for the recompression, and what gas blends to be used / breathing gas is supplied by full face mask in tank.

In the hope to have given more and adequate data I hope to get tons of info

thanks in advance

Peter van Walle

To begin... go here to download the U.S. Navy's Dive Manual...

http://www.coralspringsscuba.com/miscellaneous/usn_manual.htm

In addition to the Decompression Tables, read thoroughly the section (Chapter 22) on Recompression Chamber Operation. Formulas are given for Primary & Secondary system capacities. You are correct that 16 minutes to recompress is TOO LONG! You must blow-down the chamber at a (pressure-equivalent) rate closer to 25 feet per minute. The final depth (and whether-or-not the diver breathes O₂ from a bib)depends upon the Deco_Table to be administered, which, of course, depends in part upon the (Diver-Medic-Determined) extent of injury.

Some diving companies have developed their own sets of Tables, after many years of experience, and these are generally proprietary. However, either the NAVY (or NOAA) Tables are reknowned for the research and work that was put into them.

Please acquire (or, become FULLY informed, and develop your own) WRITTEN PROCEDURE for recompression treatment before needing same... It is all-too-easy to accidentally kill a diver who OTHERWISE might have been saved.

A commercial diver died in the Gulf of Mexico last year due to ...(believe-it-or-not)... a giant Manta Ray getting tangled in his umbilical, around the mid-water level, and "dragging" him all the way to the surface without his in-water decompression stops.

(I knew him first-hand....)

"PS"... I see post #4 just "jumped-in ahead of me... and... "Agreed"; DAN is another source for possibly obtaining some data from which to compile your overall plan ... especially given their dealings with Sport diving, such as yours.

AMEN to that! There are tables and formulae for recompression based on many complex factors including depth, time at depth, gas mix used, etc. Don't expect this to be one simple answer.

Peter,

If I were you I'd tell the people who asked you to do this, I don't know and I am not going to experiment with life support system.

Find an expert.

Wangito.

You definitely need to Contact the DAN - Diver's Alert Network, they are the best people who are knowledgeable in this arena of Diving and Decompression tanks

Website is www.dan.org

All people, Thanks for your kind help.

On the moment we have the support from the hyperbaric center from the Belgium Army. I think this wil do the job, but good advice stays welcome.

I will also contact DAN for more information and compare all info.

Best regards

PvW

DAn is a possible source but you would be better off finding and expert Diving Supervisor who worked either for the Navy or a large Commercial Diving company. When I worked for Oceaneering we put together two systems and it is not for the inexperienced or those who just run the chamber and have not built one and know not only the useage but the Engineering and regulations involved. Find a Pro!

Guest 1 , "Guest 2" here... Though I'm sure that you mean what you say, I would ask you to First think about your own words; when YOU worked for one of the big contractors, YOU assisted in putting 2 systems together. Admit it now; you didn't have any experience prior to that opportunity. Now, if you had read the previous posts {particularly those rated as good responses} you would see that the authoritative agencies were already brought up and acknowledged. The agency that holds responsibility for inspecting/testing/ and validating the performance of the finished product is not going to be so concerned about who did the work, as they will be about whether it was done RIGHT, using appropriate materials.

The outfit for whom YOU worked has killed divers of their own just as have ALL major diving contractors who have been in the business for any length of time. "Accidents" can and do happen. And, while I admit that SOME (experienced) diving supervisors might make the job go a bit smoother for these guys... give them a little credit. They are asking the right questions, doing the right research, and showing concern for their clients, that many such operations do NOT display. If they can keep their boat and other operations in order, they are most probably capable of handling THIS portion as well ... again, so long as they follow all of the good advice they've already received, develop a good written Procedure for chamber operation (per the Navy Manual, linked above) AND receive the "Good Housekeeping Seal" from the appropriate Agency.

Dear Guest 2

Thanks for your reaction. My reaction is late because we were out on sea. Yes we did the reasearch on the topic. Tank is installed and we had the full support from Belgium navy. They arranged tabels, testing and live drils on board and their hyperbaric chambers.

Feel free to visit our web site = www.fourcault.be In the near futer the foto's and tank data will be added.

My personal mail is pvw@aquatech.be

Thanks again and please do not look and the spelling faults.

Peter van Walle