What to do if nuclear disaster is imminent part 2

[Onyx]

What stops radiation, and thus shields your family, is simply putting mass between them and the radiation source. Like police body armor stopping bullets, mass stops (absorbs) radiation. The thicker the mass, the more radiation it stops. Also, the denser (heavier) the mass used, the more effective it is with every inch more you add to your fallout shelter. The thickness in inches needed to cut the radiation down to only 1/10th of its initial intensity for different common materials is: Steel 3.3", concrete 11", earth 16", water 24", wood 38", etc. The thickness required to stop 99% of the radiation is: 5" of steel, 16" of solid brick or hollow concrete blocks filled with mortar or sand, 2 feet of packed earth or 3 feet if loose, 3 feet of water. You may not have enough steel available, but anything you do have will have mass and can be used to add to your shielding - it just takes more thickness of lighter wood, for example, than heavier earth, to absorb and stop the same amount of radiation. Increasing the distance between your family and the radiation outside also reduces the radiation intensity.

The goals of your family fallout shelter are:

To maximize the distance away from the fallout 'dusting' outside on the ground and roof

To place sufficient mass between your family and the fallout to absorb the deadly radiation

To make the shelter tolerable to stay in while the radiation subsides with every passing hour
While a fallout shelter can be built anywhere, you should see what your best options are at home or nearby. Some structures already provide significant shielding or partial shielding that can be enhanced for adequate protection. If you do not have a basement available, you can still use the techniques shown below in any above ground structure, but you'll need to use more mass to achieve the same level of shielding. You may consider using other solid structures nearby, especially those with below ground spaces, such as commercial buildings, schools, churches, below ground parking garages, large and long culverts, tunnels, etc.. Some of these may require permissions and/or the acquiring of additional materials to minimize any fallout drifting or blowing into them, if open ended. Buildings with a half-dozen or more floors, where there is not a concern of blast damage, may provide good radiation protection in the center of the middle floors. This is because of both the distance and the shielding the multiple floors provide from the fallout on the ground and roof.

Bottom Line: choose a structure nearby with both the greatest mass and distance already in place between the outside, where the fallout would settle, and the shelter inside.