Whether setting up a guardrail system around the perimeter of a roof or closing off a floor opening, the system will prevent personnel from falling to a lower level, thus eliminating the fall hazard. This system can protect employees with little or no training, special maintenance or gear. The system can be used for unprotected roof edges, floor hatchways or chutes, leading edge decks, floor or wall openings, elevator shafts, and more. The Portable Construction Guardrail Stanchion can be installed on a parapet wall or on the edge of a slab. In either configuration the clamp may be used on structures 6 to 24 in. (15.2 – 61 cm) thick. The rapid thickness adjustment design speeds installation.