Positive Air Pressure 2

[glandheim]

My wife and a good friend of mine are two people who are uncomfortable at high elevation (low ambient air pressure). I want a cabin in the mountains, but my wife gets severe headaches as does my friend who _does_ own a cabin in the mountains.

I should think it would be relatively easy to keep the bedroom at high enough air pressure for sleeping. A centrifugal pump attached to an air-to-air heat exchanger looks like a good bet, but I have no idea how to determine what is needed to adequately increase the ambient air pressure.

Are there off-the-shelf systems to do this? Everything I see is geared toward laboratory use.

Thanks.

Greg Landheim
glandheim@charter.net

 

[Focht3]

Well, let's see...

Let's start with a 1 psi pressure increase - it will make it easy to "scale" the results of the calculation to other pressure increases. If the room has a wall that's 8 feet high and 12 feet wide, that's 96 square feet. Multiply that by 144 - to get square inches - and we have 13,824 square inches. That means the wall must be able to withstand a lateral air pressure thrust of almost 7 tons. At a 5 psi boost, the force is around 69,000 pounds - over 34 tons of force.

Depending on the cabin's altitude, you will need 2 to 4 psi pressure increase to achieve a "sea level" feel. It's 2.6 psi at Denver; and it increases with altitude. So figure you'll "only" need to resist a 17 ton thrust in the Mile High City.

Take a trip to the beach; you're not as likely to destroy any dwellings that way.

 

[glandheim]

1) I intend to build the structure from the ground up.

2) Sea-level is not necessary. A compensatory elevation difference of a couple of thousand feed should be adequate.

3) The structural problems are a different question. The question I asked is about the pressurization system.

Anybody have any responsible answers?

Greg

 

[BobPE]

Well, the typical mechanical systems on the market for home air movement comfortably produce 1 to 3 inches WC, so they would not be of any use. I would think you could put a few thousand CF of PD blower discharge into the room, if it is sealed well, it would not take much energy once you stabalized the pressure....

Can you imagine the doors? They would have to open out, you would never be able to open them in. I think the structural questions are the real limiting factor just like focht3 said.

BobPE

 

[boo1]

Typically homes are designed for 20-40 PSF or 0.1388-0.2777 PSI. So you can see there is a magnitude in difference.

 

[Focht3]

I'm sorry if I offended you - not my intent. I had hoped that a little humor would help you see that your solution to the ladies' sensitivity to altitude, while well meaning and interesting, just isn't very practical. I had altitude sickness as a teenager while visiting friends in Flagstaff, Arizona. I was down for two days - it was awful. In spite of my personal experience and sympathy on the issue, I believe that your solution isn't practical.

Aside from the issue of the loads on the walls, you have to consider the ceiling, too. You could make the ceiling out of reinforced concrete, but it would be quite heavy in the absence of the increased air pressure - one of the design conditions that must be considered. That means thick, very expensive walls and foundations - just to hold up the ceiling. Not to mention the shear and moment forces at the connections -

How do you keep the doors sealed? They can't open into the room/house for safety reasons. And I'm not being funny here - do you plan to put "submarine" doors on these rooms? Or the whole house? And what will you do about windows? Vents for the sinks and toilets? (They are required by code.) How will you keep the air from escaping down the toilet? (A 1 psi pressure differential will lift 2.3 feet of water, and most toilet bowls only have a few inches of "seal" to keep the sewer gases out of the house.) Every opening in the structure will have to be constructed to maritime-type standards because leaks will prevent the system from working. I don't know of any homebuilders - or construction contractors in general - capable of this kind of work. At least not for a price that I could afford.

And what if a fire should occur inside? The forced air system could actually lead to a rapid spread of a fire throughout the cabin -

You could probably design a very small room for someone to sleep in - but it would be pretty claustrophobic, and probably unsafe. Or two separate structures - with kitchen, bathrooms, etc. in one and living/sleeping quarters in the other. But it will still be damn expensive.

I still think the beach will be a lot cheaper, and less of a headache. Or build the cabin at an altitude that your wife can tolerate - without a pressurized system.

 

[glandheim]

Thanks for all of the feedback.

And sorry to focht3 for getting miffed. I had knee surgery today and was probably more touchy than I should be.

The containment/sealing problems just didn't strike me as being that tough, since I was looking at it purely as sleeping quarters, isolated from the rest of the house. It would be a once-a-day thing.

The issue of drains hadn't occured to me - who wants to depressurize to take a leak in the middle of the night?

Claustrophobia is a serious issue. Frankly, I thought the hardest engineering problem would be a nice window:}

I'm in the data gathering/exploratory phase right now.
Probably a better solution would be to increase the oxygen content in the air.

The beach is too bar away, and getting a new wife is out of the question...

I am surprised that I haven't found a solution to this problem on-line. I guess most people who have altitude problems just don't go up there. It's never been an issue for me.

Thanks to all...

Greg

 

[chicopee]

Glandheim, to appeal to your sensibilities, forget about your dream home in the mountain. Sure, you could pressurize a ,mountain cabin but what is the point, soon or later you will want to go outside of your protective environment for hikes and enjoyment of the weather.

 

[BobPE]

you could probably get an inexpensive hyperbolic chamber on ebay.....something the Russians used since they were believers in medical treatment with them.

It would be a great conversation piece in the cabin, you could fit a few people in and get piss drunk, adjusting the pressure to make the CO2 come out of the beer...LOL....

It is an overwhelming problem in relation to a house, that is why your search did not return any results becuase the engineering is too expensive to make reality...

The submarine doors would work great, but what if your house developed a leak in the middle of the night and went through sudden decompression, you would be sucked out the window and thrown out into the woods....(just kidding, I had to apply the airplane decompression thing they show on TV all the time...LOL)...

BobPE

 

[snafuman]

See your doctor. There are prescription medications that some climbers us for altitude sickness. Maybe they could be of some help

 

[BigH]

Hear! Hear! Good to see that a new wife is out of the question!! Bravo - The medical way might be the way to go. Perhaps an oxygen tent over the bed like we have to do for the 'skeeters.

 

[cvg]

Greg - Don't give up yet - I also suffer from altitude sickness. I take a trip to Keystone (10,000 ft msl) every March to ski. I feel lousy for the first 2 or 3 days. By the end of the week, I am just fine. Most people will acclimate to the elevation over time. Consider having your wife see her doctor and get a prescription for Diamox. This may prevent the problem. See the following website.

http://www.cdc.gov/travel/diseases/altitude.htm

 

[glandheim]

Thanks for the link.

The greatest difficulty in finding a solution is that it is not ME who has the problem. It's my wife. She has a better solution: Don't go where she's uncomfortable.

I need a solution that doesn't require her to do anything except show up.

Greg