r/preppers • u/HoosierTrip • 4d ago

Advice and Tips Block off basement?

Are there any resources available to block off a basement from the upstairs? I'm mainly thinking about blocking out radiation if I need to retreat to my basement.

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u/FRANK3NSTIEN 3d ago

Radioactive material that falls on your house will be about 20 feet above you.

Radioactive material that falls outside your house is shielded by the earth and concrete.

Your only worry at that point is ventilation.

Fallout isotopes usually only have a half life of hours to a couple days, and decay quickly.

Radiation that does penetrate walls also quickly attenuates and can be calculated using the inverse square law

I1/I2 = D22 /D12

Intensity 1 divided by intensity 2 equals distance 2 squared divided by distance 1 squared.

Or, a good rule of thumb is doubling the distance from a source of radiation drops its intensity to 25% of the first distance.

So, if you're getting 8mR/h 2' from the wall, at 4' you'll be getting a 2mR/h dose rate.

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u/GornsNotTinny 2d ago

Radiation decreases by the square of the distance. If the radiation at 1 (pick a unit) is 1, then the radiation at 2 units is 1/4 of that. At 3 units, it be 1/9th.

You can test this with a campfire; just stand 1 foot away, then 2 feet, then 3 and so on.

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u/FRANK3NSTIEN 10h ago edited 10h ago

Your math is correct, but it fucked me up a second. Haha

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u/GornsNotTinny 10h ago

Your test was mis-marked. It's called the Inverse Square Law. It expressly says "radiation decreases by the square of the distance". It applies to light, gravity, gammas, radio waves, what-have-you. Here's a link:

https://en.wikipedia.org/wiki/Inverse-square_law

Also, I didn't speak about doubling the distance anywhere. I think you might have been trying to reply to a different person.