18.14 Improvised fallout shelters (Kearny method)

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Nuclear War Survival Skills, by Cresson Kearny, originally published in 1979 by Oak Ridge National Laboratory and in the public domain, describes shelters that inexperienced families built in field tests with hand tools. They are useful if you have land (a ranch, rural property, a house with a large yard) and days of warning. In an apartment complex they are not an option: you can't dig in the common areas, hard or rocky soil (caliche) makes it very difficult, and there isn't enough time. The principle is explained here, not the plans.

The principle

Earth on top: every 3.6 in (9 cm) of packed earth cuts radiation in half. In his log-roofed trench shelter, Kearny uses a layer of earth 30 in (75 cm) thick; according to him, more than 36 in (90 cm) adds little protection unless the trenches are also lengthened. With about 3 feet (90 cm) of earth on top, the protection factor reaches the thousands (chapter 15).
Below ground level: the surrounding earth blocks radiation from fallout deposited on the nearby ground.
Narrow entrances with a bend: Kearny dug the entrance and emergency exit trenches only 22 in (56 cm) wide. A narrow opening and a right-angle turn let through much less radiation than a straight, wide entrance.
Ventilation: in hot weather, a full shelter must be ventilated and cooled with enough outside air; he designed the KAP pump for that (plans in his book).
Two exits: an entrance and an emergency exit at opposite ends.

Two designs, in brief

Door-covered trench shelter: a narrow trench as long as needed for the occupants, roofed with interior doors (hollow-core ones, taken off the house) laid across it, covered with plastic and then with the excavated earth in a mound. In Kearny's tests, one family finished it in 34 hours.
Log-roofed trench shelter: the same, but with logs or poles laid across as the roof; it holds more earth on top.

A “very good” shelter, according to Kearny, reduces the occupants' dose to less than 1/200 of what they would receive outside.

Figure 18.3. Simplified cross-section of a covered trench shelter based on Kearny's principle (Oak Ridge National Laboratory). It is not a construction plan: dimensions, roof, and ventilation are in the original work. — **Figure 18.3.** Simplified cross-section of a covered trench shelter based on Kearny's principle (Oak Ridge National Laboratory). It is not a construction plan: dimensions, roof, and ventilation are in the original work.