# Venting a concrete safe room



## jusolson (Nov 7, 2009)

Okay guys, I'd love to hear some options about my project. Last summer we built our new custom house. One feature I wanted to incorporate was a concrete safe room. Well our builder that did the plans suggested that use the space under the front porch for this purpose. So that's what we did. I actually really like it. It has lots of room, uses space that would have otherwise just been backfilled, and lets face it, kinda has some wow factor:thumbsup:. Anyways the builder just got the room built for us, and it will be up to me to finish it out, e.g... install a door, shelving, ect... Well the one thing I want to address that never really recieved any attention during the building phase is venting the air inside the room. I've attached the floor plan of the space and I am looking for sugguestions on how to accomplish this. My initial thinking is boring one hole above the door way for an intake vent, and then bore another hole on the opposite side of the room on the angled wall for an exhaust fan of some sort to pull the air across the room. This is all pretty much DIY, and I don't think it needs much air movement. Just enough to keep the humidity in check. I am planning on using a vault grade fire proof steel door for the entry. Would it be wise to incorporate some type of fire damping into the ductwork? How would I accomplish this? Thanks for any and all help in this project!


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## beenthere (Oct 11, 2008)

Min of 7.5 CFM per person.

Intake an exhaust of a safe room are generally ran so its difficult for an intruder seal them off, or to introduce smoke or other agents into it.


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## paintdrying (Jul 13, 2012)

are you storing Christmas decorations or is this a panic room? Did the builder run a floor drain?


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## mikegp (Jul 17, 2011)

Watch the Jodie Foster flick first.


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## jusolson (Nov 7, 2009)

This room will primarily be use to used to store valuables, memorabilia, paper and electronic documents, ect... I'm hoping to keep the christmas decor OUT of here. I've got a whole different space for that crap. Its second function will be a storm shelter. The house is located on a farm out in the country, so it will offer some peace of mind when the weather turns really stormy. I have no interest in it being used in a "panic room" situation. ( seen the movie - :thumbup But in the small percentage that a situation would arise, I suppose it could stand in for one. The room does not have a floor drain. I thought of this during construction. But reasoned that if water could get in, it could also get out and reach the drain in the basement about 20 ft away. I do like the idea of it being fire proof, so the house could burn down around it and everything inside would be safe. So I'm not sure how to keep smoke out, while still moving the air inside.


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## JScotty (Jan 14, 2013)

jusolson said:


> This room will primarily be use to used to store valuables, memorabilia, paper and electronic documents, ect... I'm hoping to keep the christmas decor OUT of here. I've got a whole different space for that crap. Its second function will be a storm shelter. The house is located on a farm out in the country, so it will offer some peace of mind when the weather turns really stormy. I have no interest in it being used in a "panic room" situation. ( seen the movie - :thumbup But in the small percentage that a situation would arise, I suppose it could stand in for one. The room does not have a floor drain. I thought of this during construction. But reasoned that if water could get in, it could also get out and reach the drain in the basement about 20 ft away. I do like the idea of it being fire proof, so the house could burn down around it and everything inside would be safe. So I'm not sure how to keep smoke out, while still moving the air inside.


 They actually make special dampers that spring closed and are help open by a peice that melts at high temperatures. It would allow ventilation, but if the house caught on fire the heat would melt the peice holding the damper open & the damper would spring shut not allowing the smoke & fire to enter.

It's usually used in HVAC duct, but seems like it would work for what you're needing. It's called a fire damper & you can get them at Grainger.


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## yuri (Nov 29, 2008)

If you are going to spend $$ to run a exhaust fan and probably quite a few to buy those fire dampers why not just buy a decent portable dehumidifier and put only one damper above the door. that way if you buy a good one that has a digital control you can set it at 35 or 40% RH and have accurate control. the other 2 vent method will just give you whatever humidity you have in the basement in there. Your basement may be like mine and it can be cold and damp. I have a high quality Simplicity from Sears dehumidifier in my basement and it keeps the humidity perfect and warms it up a bit. Dehumidifiers give off heat so you would still need one smaller outlet or the room may get too hot. I would not just keep important pics down there w/o a dehumidifier. fire damper with a lead fusible link.


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## eclark (Jan 23, 2012)

Bonus to that idea is that the room could double as a humidor.


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## jusolson (Nov 7, 2009)

So I checked out the Grainger site and those fire dampers look like they would work great!... So how about this plan, would a 4 in diameter be enough? Bore a 4" hole above the door inbetween the floor joist cavity, then rau duct work from the damper to a standard wall/floor grate mounted in the ceiling of what will become my office right off of the storm shelter. Then just keep a humidifier in the room? The floor does have a few loops of pipe in it for radient floor heating thats connected to the rest of the basement. Would the room become too hot with a humidifer and not a second intake/exhaust?


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## yuri (Nov 29, 2008)

Hard to say but you would only need the smallest size dehumidifier as it is doing only 1 room. Mine does the entire 1400 sq ft basement. Unless it is really damp down there then it won't run or use any electricity or give off heat. The secret to keeping humidity down is to insulate the basement walls very well with glued on styrofoam or that spray on insulation. Then you don't need any vapor barrior and it keeps the temp higher which reduces the humidity level. Point being that if you insulate those walls and basement very well you may never have a humidity problem and one open vent may be all that you need. I would try insulate everyrhing very well as it is great value for your $$ and then see if you really have a problem B4 buying more equipment/doing more work etc. My basement is not fully finished as I have not got around to it but other houses I have lived in when the basement was fully finished were warm down there and not damp. Insulation pays for itself with the NRG savings. I would get that sprayed on stuff as it hermetically seals the walls. Apparently the Red Sea is going to rise again/re-appear soon and hopefully you will be OK. Da*mn we got a lot of snow standing around here.

http://www.icynene.com/


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## jusolson (Nov 7, 2009)

I think I have the basement itself pretty well insulated. The basement walls are actually a wood/ foam panel construction. 8" thick with studs every 12" and a high density foam between then sandwiched with plywood both sides. The safe room however is all concrete. And even that has a layer of 2" foam on the outside before it was back filled. The only place I would be concerned about moisture in the room is the ceiling. It is pored concrete, but like I said before, this room is below the outdoor porch. So I have seen some moisture wicking through from above. I do plan on sealing the concrete porch this spring to help stop that moisture from coming through. Maybe I'll just do the two hole vent thing with some sort of inline fan tied to the furnace to move a little air through it?


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