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Calculating Total Fall Distance — TFD

Per ANSI Requirements

Description

Calculating Total Fall Distance is needed since per ANSI requirements, a fall arrest harness should be anchored in a manner that limits free fall to the shortest possible distance of 6 feet or less. The use of Energy Absorbing Personal (EAP) lanyard such as the shock absorbing Lewis SLOWSTOP™ lanyard is highly recommended to reduce fall arresting forces. However shock absorbers can elongate up to 3-1/2 feet. This elongation distance must be considered when choosing a tie-off point.

Calculating Total Fall Distance — TFD

TFD = Length of Lanyard and/or Lifeline +
Deceleration Distance +
Height of User +
Safety Factor

Calculating TFD Example

Calculating Total Fall Distance (TFD)

Example in the figure:
Length of Lanyard = 6′
Lanyard Deceleration Distance = 31/2′
Height of User = 6′
Safety Factor = 3′
TFD = 6 + 3.5 + 6 + 3 = 18.5 ft.

2017 Catalog Page 62 – Calculating Total Fall Distance – TFD