Diving with 100% Oxygen

[TOdive123]

Hi
I've been doing hyperbaric oxygen therapy (hbot). If you're familiar with this I have a couple questions. HBOT is basically a person breathing 100% oxygen at 1.5-2 ATA for about an hour. So if a diver were to have a tank full of 100% oxygen and went diving at about 60 feet in salt water (this is about the same ATA), and if you dived for an hour at that depth, would there be any dangers? why? wouldn't it be the same as being in a pressurized capsule, except the capsule is the water?
Thanks all!!

 

[Bill]

1.5 ATM is less than 20 feet in the sea. You've left out many factors. Sixty feet for an hour is very dangerous.

 

[TOdive123]

1.5 ATM is less than 20 feet in the sea. You've left out many factors. Sixty feet for an hour is very dangerous.

Would you be able to explain this to me, I thought at 60 feet it was about 2ATA. What would be a safe depth? Or less time at a deeper depth?

 

[SubSub]

Rougly 1atm / 10m (about 30ft) underwater depth. At the surface you're already at 1atm, so at 10m you're at 1+1atm = 2atm, at 20m you're at 3atm and so on.

You can check this calc.
http://www.calctool.org/CALC/other/games/depth_press

 

[NoFair]

Hi
I've been doing hyperbaric oxygen therapy (hbot). If you're familiar with this I have a couple questions. HBOT is basically a person breathing 100% oxygen at 1.5-2 ATA for about an hour. So if a diver were to have a tank full of 100% oxygen and went diving at about 60 feet in salt water (this is about the same ATA), and if you dived for an hour at that depth, would there be any dangers? why? wouldn't it be the same as being in a pressurized capsule, except the capsule is the water?
Thanks all!!

At higher pressure 100% oxygen is toxic so diving at higher depth is dangerous. During peacetime Norwegian military divers have a max depth of 7m when on pure oxygen (at least when I was serving). This is due to several accidents world wide with military divers dying from oxygen poisoning. In the old days 10-20m was considered safe, but it obviously wasn't.

 

[Hasan sünear]

Oxygen has toxic effects on more than 1.6 ATA and it is approximately 21 ft (7 m) . if you dive more than 21 ft you have very short time. When you spend much time in depht more then 21 ft you might have your centeral nervous system paralysed

 

[Bill]

One more caution. O2 tolerance can vary, both day to day and individual to individual. Resting tolerance is not the same as active.

 

[efattah]

I have done 20m (3atm) in a recompression chamber on 100% O2. The timing was Navy Table 6 which I think was 15-20 minutes at this pressure, then taking 5 minutes breaks on regular air (21%). It went on for hours.

The difference in the ocean is you are moving and metabolizing oxygen faster. In the chamber you are motionless, and if you have a seizure then the doctor can help you.

During extreme oxygen pressures, superoxide anions rapidly accumulate in the blood. The body attempts to detoxify these ions by using SOD (superoxide dismutase). The body's supply of SOD is rapidly consumed by the accumulating superoxide ions. When the SOD supply is depleted, the superoxide ions accumulate dramatically, and this causes hyperexcitation of the brain and nervous system, leading to hyperoxic convulsions/seizure.

Oxygen at high pressure is also very narcotic, more than nitrogen is.

The Navy found that while fasting, divers could withstand high O2 for longer, before getting seizures. The body's general state of health, metabolic rate, and natural antioxidant capacity (SOD level) all play a big role. When all the factors are perfectly aligned, you could theoretically last quite a long time at 20m on O2, but it would be russian roulette and it could be fatal....

 

[Bill]

Thanks for stepping in Eric. Sixty years ago we lost a club member using the 'beach ball rebreather' and I had an incident using home made open circuit gear with welder's O2.

 

[TOdive123]

I have done 20m (3atm) in a recompression chamber on 100% O2. The timing was Navy Table 6 which I think was 15-20 minutes at this pressure, then taking 5 minutes breaks on regular air (21%). It went on for hours.

The difference in the ocean is you are moving and metabolizing oxygen faster. In the chamber you are motionless, and if you have a seizure then the doctor can help you.

During extreme oxygen pressures, superoxide anions rapidly accumulate in the blood. The body attempts to detoxify these ions by using SOD (superoxide dismutase). The body's supply of SOD is rapidly consumed by the accumulating superoxide ions. When the SOD supply is depleted, the superoxide ions accumulate dramatically, and this causes hyperexcitation of the brain and nervous system, leading to hyperoxic convulsions/seizure.

Oxygen at high pressure is also very narcotic, more than nitrogen is.

The Navy found that while fasting, divers could withstand high O2 for longer, before getting seizures. The body's general state of health, metabolic rate, and natural antioxidant capacity (SOD level) all play a big role. When all the factors are perfectly aligned, you could theoretically last quite a long time at 20m on O2, but it would be russian roulette and it could be fatal....

Ok thanks for this!
So if I were to stay at about 1.4 or less ATM and be stationary without swimming around, breathing oxygen, for about an hour; I would be able to do this somewhat safely and I could get the benefits of pressurized oxygen?

 

[Hasan sünear]

Ok thanks for this!
So if I were to stay at about 1.4 or less ATM and be stationary without swimming around, breathing oxygen, for about an hour; I would be able to do this somewhat safely and I could get the benefits of pressurized oxygen?

İf you dive less than 1.6 ATA you have 240 mins dive time , according to diving manuel 6.