SLIDE NO. 51.-Group fallout shelter for 240 persons.

a basement. We conceive of this as a dual-purpose structure. For schools the structure could be used to house such activities as a cafeteria, library, musicrooms, exercise space, and so forth. It could, of course, be used for classrooms, but many school authorities may frown upon confining students underground for the entire school day, even though year by year we are spending more and more of our time in closed, air-conditioned structures without the benefit of sunlight and natural fresh air. This shelter will provide excellent protection from fallout radiation, except in the limited areas of very high intensity fallout.

Slide No. 52: This next slide depicts the basic underground family blast shelter designed to accommodate up to six adults and protect them from the effects of initial radiation, heat, blast, and fallout radiation. This structure is designed to be constructed entirely below ground with a protective mound of earth above it. The design is such that excellent protection is provided against all of the effects of nuclear weapons, including initial radiation, at an overpressure range of 30 pounds per square inch or higher. In actual tests in 1957

at the Nevada test site the structure sustained without damage overpressures more than double the 30 pounds per square inch for which it was designed. It is our plan to further test this shelter in the Pacific under the long-duration megaton weapons. There appears to be no question that it will be more than adequate for its design overpressure even under these more severe conditions.

FAMILY BLAST SHELTER (4 TO 6 PERSONS)

SLIDE NO. 52.-Family blast shelter (4 to 6 persons).

Slide No. 53: The shelter shown in this next slide was originally designed for industry, particularly for closed-down crews. As you know, steel mills, chemical processing plants and other industries of this type can not be simply abandoned without being self-destructive. They can, however, be closed down in a period of an hour or two so they will not be self-damaging, provided crews can return after a day or so. This situation may exist in many of the target areas which are not hit by the enemy or which are only partially destroyed. This

SLIDE NO. 53.-Expandable blast shelter (25 to 100 persons).

shelter was tested at the Nevada test site in 1955 at an overpressure of approximately 100 pounds per square inch and was essentially undamaged It could, undoubtedly, withstand higher overpressures. Complete protection is provided in this design against all of the effects of nuclear weapons. The design is such that the shelter can be built in its basic size to accommodate about 25 or 30 persons, or lengthened without modification of structural design to accommodate 100 or more persons.

Slide No. 54: The next slide shows a preliminary design we have made of an underground rectangular reinforced concrete shelter which may serve as a school cafeteria. Construction drawings and specifications have not been completed for this shelter. It can be designed for either fallout or blast protection.

SCHOOL SHELTER WITH CAFETERIA

SLIDE NO. 54.-School shelter with cafeteria.

Slide No. 55: This slide shows the underground garage shelter which was tested at Nevada in 1957 at an overpressure of more than 30 pounds per square inch without damage to the shelter proper. In addition to protection against blast, it provides protection against the effects of initial radiation, heat, and fallout radiation.

UNDERGROUND GARAGE SHELTER

SLIDE No. 55.-Underground garage shelter.