An apparatus for safely evacuating a person within a prescribed weight range from a multistory building by enabling the person to exit from the interior of the building to the outside very quickly and to descend to the ground or lower surface alongside the exterior of the building to attain a descent speed of less than four feet per second to land injury-free, the apparatus comprising a housing, a harness affixed to the housing for affixing the housing to the person, a cable of predetermined length within the housing, having a free-end with a securing member for affixing it to an anchorage proximate the descent point, and a descent slowing energy dissipating mechanism within the housing driven by the playout of the cable as the person descends, which enables the person to attain automatically within his descent a descent speed of less than four feet per second determined by the intersection of the graph of the curve that describes the rate of energy dissipated as a function of the descent speed and the graph of the line that describes the rate of potential energy released by the total descending weight as a function of descent speed where the slove of the graph of the rate of energy dissipated curve exceeds the slone of the graph of the rate of potential energy released line.