Another type of shelter which gives excellent fallout protection can be built as an added room to the basement of a home under construction. It would add about $500 to the total cost of the home. The shelter illustrated in figure 12 is based on such a room built in a new home in the Washington, D. C. area in the Spring of 1959.

Important considerations common to each type of shelter are:

Arrangement of the entrance.

Ventilation.

Radio reception.

Lighting.

The entrance must have at least one right-angle turn. Radiation scatters somewhat like light. Some will go around a corner. The rest continues in a straight line. Therefore, sharp turns in a shelter entrance will reduce radiation intensity inside the shelter.

Ventilation is provided in a concrete block basement shelter by vents in the wall and by the open entrance. A blower may be installed to increase comfort.

A blower is essential for the double wall shelter and for the underground shelters. It should provide not less than 5 cubic feet per minute of air per person. Vent pipes also are necessary (as shown in figs. 9, 10, and 11), but filters are not.

Radio reception is cut down by the shielding necessary to keep out radiation. As soon as the shelter is completed a radio reception check must be made. It probably will be necessary to install an outside antenna, particularly to receive CONELRAD broadcasts.

Lighting is an important consideration. Continuous low-level lighting may be provided in the shelter by means of a 4 -- cell hot-shot battery to which is wired a 150 -- milliampere flashlight type bulb. Tests have shown that such a device, with a fresh battery, will furnish light continuously for at least 10 days. With a spare battery, a source of light for 2 weeks or more would be assured. A flashlight or electric lantern also should be available for those periods when a brighter light is needed. There should be a regular electrical outlet in the shelter as power may continue in many areas.