I think the idea is that you make it dust-tight rather than air-tight. It would be quite hard to make a room so air-tight that you suffocated.

It probably doesn't need to be completely dust-tight, either. With radioactivity, more exposure is worse, and any reduction can help. A biological attack would be another matter.

Usually what gets you is not absence of oxygen but presence of carbon dioxide. Positive-pressure is a good thing, though, if you can keep it up.

I hope you are not going to startup your mini stove or light a candle in an oxygen rich environment. You probably won't have to worry much about the emergency after the explosion.

Another home filtration system is from Radius Defense at http://www.bombshelters.com/ . I don't have any connection with them, except to drool over their stuff, which has a reputation for being the best-engineered blast/fallout shelters.

As an aside, here is a link to a 2001 CBS News piece on the increased popularity of emergency shelters in general: http://www.cbsnews.com/stories/2001/12/08/archive/main320577.shtml

Steve

This is a good point. I have MRE's, and Chemlights for this setup. I should have mentioned that. NO FLAMES, FIRES, OR ANY OTHER SOURCE OF IGNITION UNDER THESE CONDITIONS!!!

I believe the idea of using duct tape, is it was designed (as it's name suggests) to seal air leaks in duct joints. Masking tape does not have the strength nor adhesion required to do that. Of course in an emergency grab whatever you can find. Another thing with duct tape is it's versitility. I have even used it as a fan belt on my truck to get back out of the woods. It can lay around almost forever and still be somewhat usable--other tapes such as masking tend to dry out and become unusable. I keep several types of tape handy and usually try to use the one designed for the job but if I was limited to only one to perform for all, I would choose the duct tape. Just an opinion for what it's worth.

Part of the problem is a misunderstanding of the duct tape and plastic sheeting to seal up a room. Yes you can seal it up well enough to die by using up the air inside and that is how the design is suppose to seal a room.

The errors come from the idea is this is for all situations. The original design was for shelter rooms in case of chemical attacks nothing else. The idea is that most military chemical attacks do not use what are called presistant agents. That means that they disipate in a short [a couple of hours] so your own troops can move in without the need of protection gear. The idea originated and has been most used in Israel speially during the gulf war.

The idea is for short term duration and being cheap enough for large masses of people. Even something like a dirty bomb it can allow the majority of the contamination to settle. Then you can would have time [such as an attack in the middle of the night] to don protective gear, plan an escape route out of the effected area. and then exicute it as quickly as possable. Thus minimizing exposure. The time such a shelter would provide will allow a more controlled and efficent escape over a grab and run situation.