Calculating Fall Clearance Distance: Dalloz Fall Protection

When selecting connecting devices and anchorage connectors, it is important to understand how to calculate potential fall clearance distance. Fall clearance distance is defined as the height at which a worker must attach to an anchorage to avoid contact with a lower level.

Calculating Fall Clearance Distance Using a Shock-Absorbing Lanyard and D-Ring Anchorage Connector

First, add the length of the shock-absorbing lanyard (6 ft.) to the maximum elongation of the shock absorber during deceleration (3-1/2 ft.) to the average height of a worker (6 ft.).

Then, add a safety factor of 3 ft. to allow for the possibility of an improperly fit harness, a taller than average worker and/or a miscalculation of distance.

The total, 18-1/2 ft. is the suggested safe fall clearance distance for this example.

NOTE: Should the shock-absorbing lanyard be used in conjunction with a cross-arm anchorage connector or other, the additional length of the anchorage connector must be taken into consideration.

Calculating Fall Clearance Distance Using a Retractable Lifeline

First, add the maximum free fall distance (2 ft.) with a retractable lifeline to the maximum deceleration distance (3-1/2 ft.) to the average height of a worker (6 ft.).

Then, add a safety factor of 3 ft. to allow for the possibility of an improperly fit harness, a taller than average worker and/or a miscalculation of distance.

The total, 14-1/2 ft. is the suggested safe fall clearance distance for this example.

NOTE: When using a retractable lifeline, the distance is calculated from the point where the retractable attaches to the back D-ring of the worker’s harness.