Freefall Distance

Freefall distance: The vertical displacement between the onset of the fall and just before the fall arrest system begins to apply force to arrest the fall. Also called fall clearance, this distance excludes deceleration distance, and lifeline/lanyard elongation, but includes any deceleration device slide distance or self-retracting lifeline/lanyard extension before they operate and fall arrest forces occur.

OSHA has specific guidelines for Freefall Distance with safety equipment.