Patent ID: 8322085

Claim:
A structure for the protection of occupants comprising: prefabricated metal components to be assembled inside an existing structure, the prefabricated metal components being defined as four corners, two columns, interior and exterior floor plates, braces, interior and exterior wall plates, interior and exterior top plates, plugs, and at least one door, wherein the prefabricated components are assembled to form cavities and wherein the cavities are filled with concrete ballast material; wherein openings are provided for said plugs at select locations for filling and checking level of concrete ballast material in a prescribed order; ventilation in the at least one door and in at least one wall formed from said interior and exterior wall plates, wherein the ventilation is baffled and utilizes slots, wherein the door comprises a back plate as well as a baffle plate; and wherein the structure is adapted to be expanded in size by increasing the quantity of said prefabricated metal components.