A nuclear bomb shelter is an enclosed space that is designed to protect its occupants by minimizing the effects of gamma rays, fallout and radioactive debris impact. The shelter shields reduce the amount of gamma rays by a factor of up to a 1000. The good news is that the shelter can be dusted and shielded 10 times using any material that can reduce gamma rays effects by 50 percent.
The following are shields that are known to reduce the intensity of gamma rays by half: 150 m of air, 1 cm of lead, 6 cm of concrete, and lastly 9 cm of packed dirt. When the thickness of shields is increase, the shielding ability also increases. Therefore, one practical shield used in the shelter have 10 halving-packed dirt thicknesses to ensure the gamma rays are reduced 1024 times.
Normally, a convenient nuclear bomb shelter is made by a trench roofed powerfully and buried by 1 m of dirt. The trench portions entrances should be at right angles. This is to make sure that the gamma rays effects are not felt inside. Below the surface of the shelter, a plastic sheet should be put to prevent water from entering inside.
Dry earth covering the shelter is a very good thermal insulator, thus, within a period of 10 -15 days of inhabitancy, the shelter will become uncomfortable as it will be too hot. A good fan with flaps in all directions and a big frame should fix the hotness problem
Unfiltered air does not pose threats, thus, there is no need to put extensive filters. The human body tissues do not ingest easily any huge particles making fine dust to be less hazardous. To add salt to an injury, the fine dust that is able to pass through the entrance easily passes through the shelter.
Finally, to ensure the blast waves are not felt outside the shelter, the blast protection valves are installed at the air outlet and air inlet. There is a positive development of pressure when the filtered air is pulled in the section that is secured. One should use NBC filters for air filtration and ensure that the shelter windows do not have a view of the ground covered with fallout.