Clear Fall Distance
Clear fall distance is the minimum vertical space needed below a worker's fall-arrest connection point to prevent striking the ground, a lower level, or an obstruction during a fall arrest. In WorkSafeBC/Canadian terms, the required clearance must be sufficient to prevent contact with the surface below, and it is a planning calculation that includes free-fall, deceleration, worker height, and a safety margin.
On a manufacturing shop floor, clear fall distance is checked before any work at height, such as on mezzanines, maintenance platforms, roof access, lift work, machine guarding gaps, or overhead rigging. A supervisor or competent person verifies the space below the worker, confirms the manufacturer's allowable free-fall limits, and ensures the setup will not 'bottom out' or let the worker hit equipment, the floor, or a lower deck. The clearance check answers: 'If the worker falls, will the harness stop them before they hit something?' For roof work, WorkSafeBC notes that the reference distance changes with roof pitch, and on low-slope surfaces the distance is at least 2 m from the unguarded edge.
- Ignoring deceleration and worker-height allowance: crews sometimes measure only lanyard length and forget the deployed energy absorber and the worker's body length, which can cause bottoming out.
- Using the wrong anchor point: a low or offset anchor increases free fall and may exceed the allowable free-fall distance for the equipment or regulation.
- Assuming all systems have the same clearance: clearance varies with lanyard type, absorber design, user weight, and manufacturer instructions; failing to follow those instructions can violate Canadian fall-protection requirements.
Is clear fall distance the same as free-fall distance?
No. Free-fall distance is how far the worker drops before arrest begins; clear fall distance is the total vertical space needed so the entire arrest process completes without impact.
What must be included in the calculation?
Lanyard length, deployed deceleration distance, worker height or D-ring-to-foot geometry, and a safety factor or margin.
What is the regulatory importance in Canada?
Canadian federal OHS rules require the clearance distance under a fall-arrest system to be sufficient to prevent impact with the ground or an object below, and WorkSafeBC guidance frames the hazard in terms of the distance to the next safe lower surface.