a shelter 20 to enable occupants thereof to survive a near - strike nuclear detonation as well as chemical , biological and conventional weapons attacks can be assembled by four men in thirty minutes . panels 38 are lightweight laminates of plastics and reinforcing fibers . as installed underground , the arched roof 26 of the shelter 20 is supported on a drive ring base member 28 , which is crushable to absorb , attenuate and help divert the airslap force of a nuclear detonation .