To prevent a worker on one level from falling and striking another level or obstruction below, the fall clearance needs to be determined. This is the minimum distance needed between a worker’s feet and the lower level to keep them from hitting that lower level, and takes into account the fall protection equipment available or proposed. This calculated fall clearance can’t be equal to or greater than the physically available clearance, or else the worker will risk injury and death.
Multiple factors go into making fall clearance calculations and keeping workers safe at heights.
- Free fall distance: the distance that a worker falls before the protection system begins slowing them down. The anchor point location is a big factor; is it directly over head, or down at the workers feet?
- Arrest distance: the distance it takes for a personal energy absorber to activate and slow the fall
- Harness stretch: how much the safety harness stretches and attachment points shift in a fall
- Safety factor: the additional distance to ensure there’s enough clearance between a worker and a lower level
Other applicable standards, situations, and manufacturer details may add more variables to the equation.
Making the Calculations
Required fall clearance distance = length of the lanyard + deceleration distance + height of the suspended worker + safety factor.
Your considerations don’t end at this formula, though. You’ll need to add extra feet to your deceleration distance if there’s a free-fall hazard between six and twelve feet and for workers between 310 and 420 pounds. The placement of the anchor point will also affect how the free fall distance is calculated. Always look at the user instructions for specifications and other information.
If your intended fall protection system doesn’t have enough clearance, you must consider other solutions. Moving the anchor point, using a retractable lifeline, using a guardrail system, or fall restraint system can all help protect workers at heights.
Fall Protection Safety Experts
PK Safety has been equipping workers with safety gear and knowledge for decades, and our expertise can help you. If you’re looking for advice on fall protection equipment or have workplace safety questions, contact us online or call 800.829.9580.