Float tank ventilation

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Float tank ventilation

Postby wjuniorbr on November 2nd, 2014, 2:15 pm 

Hello


I built an underground room measuring 2,5m x 3m x 2,3 just below the ground, the walls are about 20cm thick in solid concrete, the ceiling has iron structure and semi hollow bricks in the concrete, the whole room is revested in ceramic and porcelain tiles inside, the entrance is a 80cm x 80cm opening on the floor and it´s "sealed" with a wooden door. Its a flotation tank (among other names), its basically a concrete with ceramic tiles tub measuring 2,3m x 1,2m x 40cm. It´s used in sessions of 1 or 2 hours (I was thinking about longer sessions) and it should be isolated from light and sound, but Im afraid of the quantity of O2 and CO2. The room is not perfectly sealed, it has 6 "pipes" in the walls that carries the electrical wires (the pipes are long and they make many curves.
I read somewhere that CO2 from breathing accumulating in the room is more urgent than the lack of oxygen itself, that CO2 is heavier than the air, so does it accumulate from the floor up? Because if it does how should I remove it if it´s already an underground room? I cant use collers because the sessions have to be made in complete silence; I thought about making 1 or 2 holes on the door with pipes making curves inside de door, will this add enought O2 to offset the breathing (by the way the person using is completely relaxed), and will it remove the CO2 since supposedly it´s on the floor because it´s heavier than the O2?
Its in Brazil so the weather is tropical most of the year. The water in the tank is 24 hours heated at about 37 celsius, it has about 700 liters of water with about 400kg of epsom salt (magnesium sulfate). Does this water affect anything in the ventilation matter?


Sorry for the long text, there is no easy way to explain without giving details. Any idea is appreciated.
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Re: Float tank ventilation

Postby CanadysPeak on November 4th, 2014, 7:10 pm 

wjuniorbr » Sun Nov 02, 2014 2:15 pm wrote:Hello


I built an underground room measuring 2,5m x 3m x 2,3 just below the ground, the walls are about 20cm thick in solid concrete, the ceiling has iron structure and semi hollow bricks in the concrete, the whole room is revested in ceramic and porcelain tiles inside, the entrance is a 80cm x 80cm opening on the floor and it´s "sealed" with a wooden door. Its a flotation tank (among other names), its basically a concrete with ceramic tiles tub measuring 2,3m x 1,2m x 40cm. It´s used in sessions of 1 or 2 hours (I was thinking about longer sessions) and it should be isolated from light and sound, but Im afraid of the quantity of O2 and CO2. The room is not perfectly sealed, it has 6 "pipes" in the walls that carries the electrical wires (the pipes are long and they make many curves.
I read somewhere that CO2 from breathing accumulating in the room is more urgent than the lack of oxygen itself, that CO2 is heavier than the air, so does it accumulate from the floor up? Because if it does how should I remove it if it´s already an underground room? I cant use collers because the sessions have to be made in complete silence; I thought about making 1 or 2 holes on the door with pipes making curves inside de door, will this add enought O2 to offset the breathing (by the way the person using is completely relaxed), and will it remove the CO2 since supposedly it´s on the floor because it´s heavier than the O2?
Its in Brazil so the weather is tropical most of the year. The water in the tank is 24 hours heated at about 37 celsius, it has about 700 liters of water with about 400kg of epsom salt (magnesium sulfate). Does this water affect anything in the ventilation matter?


Sorry for the long text, there is no easy way to explain without giving details. Any idea is appreciated.


You have more than 500 cubic feet in the chamber. 700 L of water will occupy about 25 cubic feet. (are you sure about 700 L?) so you have close to 500 cubic feet of air space. A relaxed human generates about 1 cubic foot of carbon dioxide each hour. Anything above 1 % is dangerous (though not fatal), so you have 5 hours between air changes. You do realize that 700 L will only amount to about 4 inches of water, don't you?
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Re: Float tank ventilation

Postby wjuniorbr on November 4th, 2014, 7:51 pm 

a tub with 2,3m x 1,2m x 0.25m will hold 690L, which is about 10 inches. That´s how high it should be.
The long sessions Im thinking about doing is about 4 hours.
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Re: Float tank ventilation

Postby CanadysPeak on November 4th, 2014, 8:13 pm 

wjuniorbr » Tue Nov 04, 2014 7:51 pm wrote:a tub with 2,3m x 1,2m x 0.25m will hold 690L, which is about 10 inches. That´s how high it should be.
The long sessions Im thinking about doing is about 4 hours.


I see. I misunderstood the room layout. You still have all that air volume. However, if you are in the US, you will need to use forced ventilation or else confined space permits. What does your insurance carrier say?

Oh, you did say Brazil. Don't know anything about laws there.
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Re: Float tank ventilation

Postby wjuniorbr on November 4th, 2014, 8:38 pm 

I have no insurance.
As the ear of the person is underwater and also wearing an ear plug, I ll be running tests with forced ventilation, but as it very is close to 100% silence in there, Im still afraid it will be heard. :/
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Re: Float tank ventilation

Postby CanadysPeak on November 4th, 2014, 9:47 pm 

wjuniorbr » Tue Nov 04, 2014 8:38 pm wrote:I have no insurance.
As the ear of the person is underwater and also wearing an ear plug, I ll be running tests with forced ventilation, but as it very is close to 100% silence in there, Im still afraid it will be heard. :/


Even though I am not familiar with Brazilian law, Brazil does have some sort of regulation of confined spaces, and I urge you to find out what that is. However, you might contact a manufacturer of rebreathing apparatus to see if there is a way to react the CO2 and turn it into water and oxygen as is done in self-rescue devices.
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Re: Float tank ventilation

Postby Braininvat on November 5th, 2014, 1:35 pm 

Could a fairly simple CO2 absorber be added, like a bed of lithium hydroxide? Or quicklime, if you want to go low-budget? Or activated carbon? IIRC, the activated carbon is easy to recharge - you just blow clean air through it for a while and the absorbed CO2 is released. Sounds like your air volume is great enough that the CO2 isn't a real big concern.
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Re: Float tank ventilation

Postby wjuniorbr on November 6th, 2014, 1:58 pm 

Good ideas Braininvat, I will look into those.
Thank you
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