What does an underground corrugated steel culvert shelter offers? This shelter is designed to provide low-cost protection from the effects of radioactive fall out. Its principal advantages are that most of the structure is generally available as a prefabricated unit ready for lowering into an excavation and that it requires only simple connections and covering to complete the installation.
Space and Occupancy
This shelter has 32 square feet of area and about 120 cubic feet of space (including the entranceway). It could provide space for three persons. The addition of a 4-foot length would provide for one more person.
Availability and Cost of Materials
This type of shelter is available from steel culvert fabricators or their sales outlets in most population centers. This prefabricated shelter, including ventilation system, plastic wrap, and sandbags is designed to be sold for $150 or less, excluding delivery and installation.
Fallout Protection Factor
When the entranceway is properly shielded as shown in the drawings, the protection factor should be greater than 500.
This shelter could be expected to withstand a limited blast overpressure of 5 pounds per square inch.
A sheet metal intake vent 3 inches in diameter is provided together with a manual airblower for more than three persons. Air is vented through the sandbag closure at the entrance.
One man working with hand excavation tools should be able to complete the excavation in less than 2 man-days. Two men will be needed to roll the shelter structure into the excavation from the point at which the shelter has been delivered. If lifting rather than rolling is necessary to transport the structure, four men will be required. Time for this phase will vary upward from 1 hour depending on distance of the move. It will then take one man 4 working days to complete the covering and installation phases.
Structural Life Expectancy
The estimated life of this galvanized steel culvert shelter will be at least 10 years under most soil conditions. Under normal conditions highway culverts of similar material has been known to last indefinitely with litle maintenance.