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    Cheap Ventilation System for Underground Shelters


    Posts : 22466
    Join date : 2010-04-07
    Location : Hawaii

    Cheap Ventilation System for Underground Shelters

    Post  Carol on Fri Apr 09, 2010 2:48 am

    Cheap Ventilation System for Underground Shelters

    This chat is from another brain storming session in the Mod area. Please feel free to add your suggestions to the thread.

    Carol: I've got some design issues I need to run by some folks and one of those is air exchange for the underground shelters along with toilet facilities.

    One could use a camping chemical toilet or a composting toilet.. long term would need to be worked out where the composting toilet may be more practical but chemical for a shorter stint. One could even use a 5 gallon bucket with a lid and a small toilet seat that could be placed on top or the toilet seat type camper toilet with the plastic bags to hold waste and seal off each deposit much like the dirty diaper system. Liquid waste could be arranged to be disposed of through a gray water type of system buried along side of the shelter.

    However the air filtration system is a design issue worth exploring.

    Myplanet2: maybe composting

    Carol: There needs to be a system for air exchange for the underground facilities. Air exchange is important because of the CO2 buildup and possible radon outgassing exposure from underground facilities.

    I had this one friend who did do something along those lines in an underground safety area he put in and it utilized some type of fan for air exchange.

    We are looking at the most easy, economical way to approach all of these systems. For instance, if one were to do the aquaponics.. they could even dig trenches for the water troughs and a tank size pit for fish.. but again one would need the plastic liner, pump, some form of electricty to run the pump to provide the air for the fish.

    Myplanet2: Probably need to provide for air filtration too. Wash the air coming in.

    Carol: That depends... as if the air vent was a u-tube facing down to the ground.. much of that is safe.. as air would have to go up as compared to drop down. One could easily attach filters at different junctures if needed.

    Myplanet2: It wouldn't be hard to rig something to bring air in I've been thinking about converting an exercise bicycle for multiple uses. Take the tire off and put a pulley on instead.

    Carol: I've even see them rigged to grind flour

    Jack: An excellent way to generate electricity

    Myplanet2: Could use it to connect to an alternator to charge batteries. Could use it to pump water, or air

    Jack: Hook one up to an alternator and you've a way to charge batteries.

    Myplanet2: ...but you'd probably want something more automatic to bring air in. Most venting systems I know of are powered. Might be some sort of gravity system possible.

    Have to explore that.

    Carol: Pumps are best for water below the surface. Even if one were to store water underground this could be arranged several ways. With our house here we have a cathcment system where the water is collected off the roof and flows into a catchment tank. The problem is with electricity as a pump is required to move the water from the pump to the house. I was thinking of purchasing a generator.. but again why put money in something that requires oil?

    My friend is designing some windmills where air is captured.. through a wind tunnel and used to help airiate the water for the fish. Something like that might also be usefull for underground but again one is dependent upon wind for it to work.

    Myplanet2: An electrical free venting system would be easy if you were assured of a temperature differential inside to outside.

    Carol: Hmm, what about a EMF? How would that impact electrical systems?

    Myplanet2: Hot air rises, cool sinks. You'd just need draw strings and a spring flap like on a diesel exhaust. Open them up and away you go.

    The considerations are with heat loss. (probably not so much in Hawaii)

    Carol: They had something like that in the earthships (Taos, New Mexico)

    My Planet: Temperature regulation is pretty easy underground.

    Carol: At the back of the structure there were skylights that popped open to allow for flow of air from front to back.. also there were tubes/conduits that were down on the ground from front of the structure to the inside back of the structure

    Myplanet2: If it's real hot though, venting becomes really important

    Carol: Those were to bring in cool air

    Most underground structures can be hot or cold. Ideally, earthships were buried 4 feet down which gave a constant tempreture in the 70s no matter how hot or cold it was outside. What we may do is the type of structure I saw which had layers.. going down into the ground.

    The upper layer was designed as a greenhouse. I may have those plans around somewhere as I did find it on the net

    Myplanet2: I saw some plans for cold climates that used lots of rocks buried in the ground with liquid filled tubes running through them. Just worked by convection. heated in winter, cooled in summer.

    I saw a cool Utube video on one of those earthships. Solar through a wall of windows, recycling water three or four times. plants for air etc. Carol. The system I tried to describe above is called the "passive stack ventilation" system.

    Google found some PDF descriptions but little by way of websites with illustrations. It's basically two pipes. One at the top of the space, and the other extending to the floor. They both vent to the outside, and assume a difference in temperature, top to bottom, creating a convection. Or a difference in temp inside to outside.

    For a small space, it should move enough air to keep it well vented, and it would always be running, with no power, although a mechanical assist would be easy to rig if you needed to give it a boost.

    The only hazards I can think of would be contaminants in the outside air being drawn in, or something falling on one or both vent openings, cutting off the air movement.

    The second could be worked around by surfacing the vents beside or between a couple of boulders.

    The contaminants are harder because I don't think passive filtration systems would be up to filtering the types of contaminants which you'd be concerned about. Even the best mechanical/electrical ones don't usually cover all potential hazards.

    That's about what I found out/think on our venting. provision.

    Baggywrinkle: and for ventilation, check this out from the rubicon. These guys actually do everything they talk about

    Safe Room Squirrel Cage Fan* Fan in a can.

    and this.. Super Strong Geodesic Dome Frame tuttle tuff shelters

    Two models: Galapagos-24ft. & Snapper-16ft.

    “Galapagos-24” -9ft high, 24ft dia, 452ft/sq
    -High R Value insulation, floor, stove, solar lighting, clear hot house covers avail.

    “Snapper-16” -8ft high, 16ft dia, 200+ ft/sq

    -Same great features as the Galapagos-24

    original thread at:

    Posts : 22466
    Join date : 2010-04-07
    Location : Hawaii

    Re: Cheap Ventilation System for Underground Shelters

    Post  Carol on Fri Apr 09, 2010 2:51 am

    From Pheryllt:

    Ok, not the original piece that i referenced, but this page gives 2 styles of home made air pumps for shelter ventilation. Primary concern is adequate cfm for # of occupants, second is filtering or with channeling, removal of fallout, third is redundancy or false air vents and camouflage of real air vents. I thing i don't think they mention in the article is setting up the system to prevent being "smoked out" by angry non-sheltered crazies who want your stored food/water and or your shelter for themselves. There was in the original article a means of trenching the air supply tunnel in such a way as to prevent being smoked/burnt/or drowned out of your shelter. I'll keep looking.

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