Uhhh....97.5/2.5 mix? A week of deco?

[Joshua Smith]

This is pretty mind blowing.


http://www.nytimes.com/2008/11/23/nyreg ... wanted=all

[John Rawlings]

Wow....MAJOR Brass Ones there! I hope that they have no significant problems and that they all survive to spend what I know must be a HUGE paycheck at the end of the job.

[Dashrynn]

Wow....MAJOR Brass Ones there! I hope that they have no significant problems and that they all survive to spend what I know must be a HUGE paycheck at the end of the job.

This got me to thinking, if we use 5% of oxygen( http://members.shaw.ca/tfrisen/how_much ... person.htm) why are they only breathing 2.5%? i understand they probably need that low of a percentage to keep from oxtoxing but don't they need a minimum amount that's higher than 2.5? Or with the increased pressure they have plenty of oxygen?

[spatman]

This got me to thinking, if we use 5% of oxygen( http://members.shaw.ca/tfrisen/how_much ... person.htm) why are they only breathing 2.5%? i understand they probably need that low of a percentage to keep from oxtoxing but don't they need a minimum amount that's higher than 2.5? Or with the increased pressure they have plenty of oxygen?

they're at just over 22 ATM at 700 ffw, so their PO2 is ~.55

i think the minimum to sustain life is around .20, but i'm certainly not an expert.

[ktb]

I now know what my hell will be like. Damn.

[LCF]

It's generally taught that you require .16 to maintain consciousness. So they're fine.

Fascinating article, Josh. Thanks for posting the link. I can't imagine doing what they do, and I do hope they are VERY well paid.

[vlad]

I wonder why do they use heliox? What about High-pressure nervous syndrome?

[loanwolf]

I wonder why do they use heliox? What about High-pressure nervous syndrome?

No nitrogen, you do not get tired as fast for one thing. And the standards are set up to keep things easier you are only dealing with 2 gasses that have to be maintained over a long period. As for HPNS you get that on the first press in the chamber, once you though it and stabilize it is not a issue most of the time. Unless you really stress your self physically and or mentally then sometimes it can come back. Because Nitrogen is heavier it can add to the effects HPNS another reason for Heliox.

[scottsax]

Fascinating article. Thanks for posting!

I think my ex works for or used to work for Global.

http://www.gdiving.com/project/11

[BASSMAN]

Sign me up! (20 years ago!)
I get so much pain relief from diving I often wonder if I should find a full time dive Job somewhere.
But 20+ years working as an aircraft mechanic has it's benefits. Some too good to give up.

Great article, thanks Josh!



Keith

[loanwolf]

Sign me up! (20 years ago!)
I get so much pain relief from diving I often wonder if I should find a full time dive Job somewhere.
But 20+ years working as an aircraft mechanic has it's benefits. Some too good to give up.

Great article, thanks Josh!



Keith

all that OT and $$$$$

[CaptnJack]

Wooo hooo sounds like the NY escorts will be down there soon!

[Joshua Smith]

Looking forward to that.

[Penopolypants]

Sadly, you'll have to look somewhere other than NWDC for your escorts. Spammers do love to give us the love. They do.

[spudgunman]

wow that is crazy think of the current, what if you accidentally let go of a tool woosh!

so I didn't understand something, it sounds like they will be under water for 12 hours at a time with the whole team, but being in the tube you would only have the pressure of the column of water in the tube which in theory isn't straight down also the pressure presses out and not just down, so why would they need the crazy deco tank? and crazy low O2 I saw that "just over 22 ATM at 700 ffw," how is that calculated being in a tube is a bit different then just standing water isnt it? or is it a column of water 70 stories straight down?


crazy article! wonder if they get a pee valve that would be sort of fun. take this drinking water~!

[spatman]

so I didn't understand something, it sounds like they will be under water for 12 hours at a time with the whole team, but being in the tube you would only have the pressure of the column of water in the tube which in theory isn't straight down also the pressure presses out and not just down, so why would they need the crazy deco tank? and crazy low O2 I saw that "just over 22 ATM at 700 ffw," how is that calculated being in a tube is a bit different then just standing water isnt it? or is it a column of water 70 stories straight down?

i don't really understand what you're asking, but with saturation diving, these guys will be in a pressurized environment equal to their working depth for up to a few weeks. the chamber they stay in while not on shift and the bell that transport them to the job site are all likely pressurized to the equivalent of 700ffw.

[spudgunman]

the thing I didn't get is why the 700ft would be the depth?

[DiverChris]

[quote="spudgunman"]the thing I didn't get is why the 700ft would be the depth?[/quote]

The 700' depth comes from this line "fix a valve at the bottom of a 700-foot shaft".

It does not matter if you are in a tube or in the ocean. The weight of the water higher than your body creates the pressure. In open water it is a theoretical column of water on top of you that we think of as creating the pressure. In a pipe it may not be directly over you but the vertical depth from the surface to the bottom creates the same pressure . The water does push against the sides of the pipe but water in the ocean pushes against the water "next to" it in the same way. The pipe does not reduce the pressure, just contains it.

So diving 700 vertical feet into a pipe with fresh water is the same as diving 700 feet deep in a freshwater lake.

-Chris

[Dashrynn]

So the tube they live in is pressurized to 700 ft? Must be one hell of a breath in.

Why don't they use a 1 ata suit?

[DiverChris]

[quote][quote="Dashrynn"]So the tube they live in is pressurized to 700 ft? Must be one hell of a breath in.

Why don't they use a 1 ata suit?[/quote][/quote]

I was wondering the same thing about using 1 atm suits.

Maybe a Newt suit wouldn't fit, or would be too difficult to work in or couldn't manuver in a pipe. Maybe they simply don't have one and cant afford one.

I have zero knowledge of hard (1 atm) suits though so perhaps someone else can enlighten us.

-Chris

[selkie]

[spudgunman]

the thing I didn't get is why the 700ft would be the depth?

The 700' depth comes from this line "fix a valve at the bottom of a 700-foot shaft".

It does not matter if you are in a tube or in the ocean. The weight of the water higher than your body creates the pressure. In open water it is a theoretical column of water on top of you that we think of as creating the pressure. In a pipe it may not be directly over you but the vertical depth from the surface to the bottom creates the same pressure . The water does push against the sides of the pipe but water in the ocean pushes against the water "next to" it in the same way. The pipe does not reduce the pressure, just contains it.

So diving 700 vertical feet into a pipe with fresh water is the same as diving 700 feet deep in a freshwater lake.

-Chris

I missed the number in the article, I thought we here in NWDC just calculated it with a magic number or something thanks!

[scottsax]

I missed the number in the article, I thought we here in NWDC just calculated it with a magic number or something thanks!

It's really quite simple math. Add the RMV's of the top 7 posters on NWDC, divide by 33fsw, multiply by the number of posts containing the emoticon, and finally subtract the number of posts advertising NY Asian Escorts to get 700ffw.

I think.