Determining fall clearance is perhaps the most important aspect of fall protection. If not properly calculated, the wrong equipment could be selected for a particular job and, in the event of a fall, the result could be devastating.
Fall clearance is the minimum distance needed for equipment to arrest (or stop) a fall and keep a worker from striking the ground or the next lowest surface. It is not a simple distance calculation. There are many factors to consider, such as:
Length of Anchorage Connecter (LA) Length of Connecting Device (LC)Maximum Arrest Distance of Connecting Device (MAD) Height of Worker (HW) Safety Factor (SF) i.e., Harness Stretch, typically 2 ft. Relation of Anchor Point to Dorsal D-Ring
If the distance between the anchor point and nearest obstruction is less than the determined fall clearance, the fall arrest system will not protect a worker from hitting a lower surface.
Another consideration are situations known as swing falls. A swing fall occurs when an anchorage point is not directly above a worker. The nature of these falls means that adjusted calculations must be made.