[judicial meanz]

reference your question on sheltering in place, hope this information helps-

The air conditioning feeds to your safe room should be shut off, plastic wrapped and duct taped over, and sealed. Any method air can use to enter the room from the outside is a possible source of contamination, including floor vents too, and should be all sealed.

That includes doors, windows, etc, and sheeting them with plastic and duct taping any place air can come into the room. Essentially you are making it airtight.

It isnt required to seal it forever, because CBRN weapons disperse after some time in the open air with wind currents and all that. I would stay put until I heard an all clear on the radio, heard movement outside. Basic rule-chem weapons are heavier than air, bio weapons may or may not be, and binary weapons ( doubt they have them) are a toss up.

Another thing to consider is that CBRN weapons are heavier than air- most of the time, but not all. Some are engineered to float for longer periods of time, like the Anthrax right after the 9-11 attacks.

Mostly they will sink to the lowest level of the terrain. Listen to the news to see what the "Hang time" of the agent is, and let that help you make the decision to leave your shelter. I personally would avoid taking shelter in a low lying room, but thats my choice. You have to choose your own area, and I am sure you have.

In World War I, soldiers who got mustard gassed usually got it from taking shelter in a trench or crater wher the gas had accumulated after an attack, as well as from the initial attacks. Always remember pockets can exist, especially if it is chemical weapons, in low lying areas or terrain depressions after an attack.

The air shouldnt run out in a safe room before you get the all clear to leave. You will probably have about 1-2 days of air in that room for a family of 4.

[Timeout]

So now I'll add a chair or step ladder to my list so I can reach the ceiling to tape over the vent. Sure hope I never have to do this.

[itssoamusing]

My wife and I are going out tonight to get our supplies. We live about 25 miles outside of DC close to Dulles Airport. In preparing for this, we planned on using a room in the basement that is underground with no windows. Would it be better for us to stay in the upstairs master bedroom 3 stories up or in the basement? The oxygen thing is starting to make me wonder if we stay in the basement. Our townhouse is an end unit with extra windows in the master bedroom though. Ideas anyone?

[Ichneumon]

Any method air can use to enter the room from the outside is a possible source of contamination, including floor vents too, and should be all sealed. That includes doors, windows, etc, and sheeting them with plastic and duct taping any place air can come into the room.

Also be aware that hardwood floors leak air like a sieve. There's a quarter inch or so of air space underneath them, and the cracks between the wood slats allow the floor to "breath". If your best saferoom has a traditional hardwood floor, it's best to just carpet the room wall-to-wall with heavy mil plastic sheeting and seal the edges to the surrounding walls with duct tape.

Electrical outlets, light switches, and ceiling-mounted light fixtures are also often overlooked sources of "air leaks".