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Posted: 6/15/2007 3:29:15 AM EDT
Okay folks . . . ! I've been waiting for a guy in my neighborhood (who's a respected member of this board), to come over and give me first-hand, on-site advice on this! But . . . he's been really busy, lately!

Sooooo! I'll do my best to describe my situation, here - and, hopefully, you guys can offer some suggestions! Okay?

Alrighty then . . . where to begin . . ?

My house is built into a hill. Downstairs (in what used to be our storage room - approx 18' X 10'), I've created a "safe room," of sorts. Being the part that's built into the hill, this section of the house is the most protected. In it, I have my safe and all my ammo/equipment, food, access to water, toiletries . . . you name it.

The entire downstairs is concrete block and the room is almost completely covered with 'radiant-barrier' insulation, too. So, for a fallout shelter, it's as good as it's going to get, at my place.

The ONE thing I'm lacking is fresh air.

I have two gennys and around 50 gal's of fuel - although, I'm not yet sure how I could turn-on (and fuel), the gennys remotely. Going out to do it would kinda' defeat the purpose of the safe-room! But, that's a conversation for another day . . .

WHAT I'VE BEEN THINKING ABOUT, THOUGH, IS: . . . if I use the genny(s) DAILY (say; for cooking, cooling the fridge/freezer and drawing fresh water, etc), I shoul also be able to use it to bring in fresh, filtered air.

My question is - how?

I DON'T have a furnace or any kind of ductwork in the house. (don't ask!) Since the walls are block, it'd be pretty hard to go through a wall - to the outside, too. I was thinking, though, about cutting a hole in the ONE wall that's NOT block - and that simply goes into another, small room of the house. If I were to mount a fan in that wall, could I build a "box" around it and fill the box with some sort of filtering material?

If so, what kind of filter material? And, what kind of fan will be strong enough to pull the air through such a filter - and NOT burn itself up? (nor be so loud that we couldn't stand it!)

Also . . . if the house is (pretty much), sealed . . . will there be enough air (already IN the house), to support 4 people for . . . say: a week? (Or, until radiation levels would have dropped enough to emerge from the shelter?) The area of the house is about 30' X 60' X 2 floors. Inside the small room (from which the filtered air would be drawn - approx 6' X 10'), is a small, shuttered "window" that opens to the rest of the house.

I figure I could put a FIRST layer of filter material across that "window" for some added protection from particles in the air. Then, the air would hit the "filter box" - BEFORE being blown into the safe room.

Am I on the right track, you think?

Further . . . if I get this figured out . . . would I need an "exhaust port?" Or, somewhere for the "old" air to go? If so, how would you reccommend constructing that? It'd have to be sealed - when not in use. Right? Yet, open when positive pressure was exerted against it. Am I correct?

I know it'd be smart to have a couple CO2 sensors, too . . .

Boy! Any help will be GREATLY appreciated! I'm not all that far from Three Mile Island, after all! Plus, Gettysburg is surrounded by cities that are prime targets. Personally, I think (given the way things are looking), I should've had this done by now! Time may very well be running out!

How's that saying go - about paranoia? "It's only paranoia if . . . ?"
Link Posted: 6/15/2007 3:33:48 AM EDT
Tag for info
Link Posted: 6/15/2007 4:03:10 AM EDT
THAT'S a big HELP!!!

Here's to hoping we get some . . !
Link Posted: 6/15/2007 9:15:23 AM EDT
I have been working on something similar to what's listed on this page.

At the least...it might give you some ideas if you haven't seen it before.

Mine isn't completed and I have some of the same questions.

Squirrel Cage Fan

Link Posted: 6/15/2007 11:37:26 AM EDT

Tag for info
Link Posted: 6/15/2007 1:24:33 PM EDT

if I use the genny(s) DAILY (say; for cooking, cooling the fridge/freezer and drawing fresh water, etc), I shoul also be able to use it to bring in fresh, filtered air.

You trust the reliability of your generators enough to use them as your sole source of fresh air?

would I need an "exhaust port?"

Unless the room is poorly sealed, you will almost certainly need an exhaust outlet. Air only flows someplace if it can displace the air that's already there...
Link Posted: 6/15/2007 2:38:08 PM EDT

I have been working on something similar to what's listed on this page.

At the least...it might give you some ideas if you haven't seen it before.

Mine isn't completed and I have some of the same questions.

Squirrel Cage Fan

Thanks a lot, NHGUNNER! That's almost exactly what I was looking for! (I even HAVE a fan like that - and had wondered if I might be able to make use of it for this job!!!) That's great!

Now . . . I STILL have some issues. For instance, I can't keep positive pressure in the room, at all times. At least, not yet. I'll be using generators - for now. Although, I DO intend to get a battery-bank set-up going, ASAP. I'll need hands-on assistance for that, though.

Great article, bro! Thanks again!

ETA: Yeah. For a few days, I DO trust my gennys, that much! I've been thinking about the exhaust, too. I MIGHt just have that figured out . . !
Link Posted: 6/16/2007 7:43:32 AM EDT

If you have the money I would go with this.


Link Posted: 6/16/2007 8:08:27 AM EDT
The above link to the squirrel cage is great for individual rooms and there might be a article about positive pressurizing a apartment sized area or whole house there too.  Your best bet is to power your fan/s off of a couple deep cycle batteries and recharge them as needed.  Running a generator to provide a hour of fresh air doesn't cut it and is a waste of fuel.  You'd be utterly amazed just how much air exchange occurs within even a modern home.  During my CERT training, air gets exchanged at a rate of 4-6 times a hour I believe - I don't have my notes sitting in front of me. In a automobile it's triple that rate especially if it's moving.  

As to 'need a exhaust vent' - nope.  As soon as you turn on a pos pressure air filter the "bad air" will find its way out via floor, windows, seams, wall sockets, etc.

Link Posted: 6/16/2007 11:11:50 AM EDT
I would make sure I had a MANOMETER to measure my pressure inside the room. It is very easy to over pressure a room with a squirrel cage fan.

I would keep the room at no higher than a half inch of water column in the room. That may not seem like much pressure, but two inches of water column will blow apart 1/2" plywood with ease. When I use 2" of WC, I always build the airlock out of 3/4" plywood and I still have to brace it with 2x4's, because over a few weeks even 3/4" starts to fatigue, and bulge.

If you run 2 to 2.5 inches of WC, you will have about 11-13 pounds of force per square foot. So just for reference, a 4x8 sheet of plywood will have 352 - 416 pounds of force against it. If you have a window in your safe room, it will not hold up to this kind of pressure. As you can see, even a slight amount of change in WC is a large change in pounds per square foot. Even if you have no windows, you can stress the building itself and create cracks. You will then loose pressure, and whatever you are trying to keep out will have an easier time getting in, because you have lost your positive pressure.

I would also make sure that I had 125 cubic feet of air per hour for each person in the shelter. CDC says you need a minimum of 103 CFH per person to keep CO2 and moisture levels at a comfortable and safe level. I like a little wiggle room in this figure myself, so I make sure we have 125 CFH per person.
Link Posted: 6/17/2007 3:19:10 AM EDT
Some great info coming forward now, folks!

Thank YOU!!!

The ONE worry I have about positive-pressure is being able to maintain it. I'd wanted to get some sort of battery-bank, anyway . . . NOW, I guess I'll need one exclusively for the air-system! (How else can it be maintained, constantly?)

Also, I hadn't thought that much about biological agents. (I was more concerned with radiological) Since we live in the country, I was confident we'd be okay. Thinking on it further, however, I realize that - especially with things like Avian Flu - I might not be so safe, after all.

As for using the genny(s) . . . I had thought to "kill two birds," as it were: power the fridge, water pump, hot plate/microwave, air-system, etc, etc . . . a few times per day. I guess that would ONLY work if the room were sealed (w/exhaust). Even then, that might not be enough air coming in - huh?

Well . . . I've always been a proponent of doing things the RIGHT WAY, the first time. (Might NOT get a second chance - especially in THIS case!)

Thanks again - for the links and advice/info! I KNEW I came to the right place!
Link Posted: 6/17/2007 4:30:46 AM EDT
Have you ever considered the Kearney Air Pump? Very simple to build. Here is a link to a paper that describes it.


Go to Chapter Six (Ventilation) for info about it.

For those who've never heard of it, or him, Cresson Kearney created some significant designs for fallout protection, which are within the talents of most people capable of using a hammer or screwdriver.

The pump: Imagine a long (9' or so) hallway. Hanging from the ceiling are 3 or 4 dividers. Between each of these rise 3 or 4 dividers, rising from the floor. They are closed and sealed everywhere except where the air passes them, at top or bottom.

One end of the hallway is open to the outside air. The other end has an opening into your shelter. Just outside this opening, there is a final divider hanging from the ceiling, on hinges; there is a drawstring attached to it so it can be swung from inside the shelter. At the outside entrance, and at the inside opening, are baffles made to open and close with air pressure, sort of like butterfly valves. The person swinging the last divider can then pump air one-way through the hallway.

As the air passes between the dividers, contaminants drop onto the floor.

Here's a quick  sketch of the pump:

Link Posted: 6/17/2007 6:37:09 AM EDT
Very interesting thread.

I'm currently working on the complete design of
a shelter before I move this year.

I plan on building it using a 10 foot X 25 to 40 foot
corrugated steel drain pipe as the main
structure itself.

Similar to the stuff on Utah shelter systems,
but a little smaller ,cheaper,and with some of
my own customizable features.

Depending on what their best deal is at the time.

(A manufacturer of these is right down the
road,they auction off errors,over-runsand such)

I want to work EVERYTHING out before starting.

Especially the costs.

It's just easier and cheaper to plan it out as best as possible
before starting.

The single biggest thing I'm having problems completely
working out is a ventilation/filtering system.

The info I find isn't very good,and lacks detail.

Simply "Buy This !" supposedly all inclusive systems
that are crazy expensive.

I plan on building this in stages as money allows ,
so I REALLY need to come up with a good workable
solution that can be added on.

Ventilation will be OK for now,but eventually
I want to have filtration.
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