Calculate total fall clearance required and minimum anchor attachment height for your lanyard and energy absorber configuration.
Total Fall Clearance Required
5.25 m
Min Anchor Attachment Height
5.25 m
above lower obstruction
Formula: Lanyard + Absorber + Connector + (Worker height − D-ring height) + Safety margin. D-ring assumed at 1.4 m. Per AS/NZS 1891.1.
Total fall clearance = lanyard length + energy absorber extension + connector length + (worker height minus D-ring height above feet, typically 0.4m) + safety margin. The anchor must be at least this distance above the lower obstruction (floor, ledge, structure).
A minimum 1.0 m safety margin is standard practice in NZ and AU. This accounts for dynamic stretch in the system, body movement during arrest, and measurement uncertainties. For critical installations or where obstacles are close, use a larger margin.
The dorsal D-ring on a full-body harness is typically located at the back of the wearer between the shoulder blades, approximately 1.4–1.5 m above the feet for an average adult. This is the attachment point for the lanyard and affects how far the wearer descends during a fall before arrest.