What is Fall Factor?
The fall factor is a measure of the severity of a fall, calculated as the ratio of the potential fall distance to the length of the lanyard or rope used to arrest the fall.
Fall Factor Formula:
Fall Factor = Free-Fall Distance ÷ Lanyard Length
Fall Factor 0:
- Anchor point is above the worker, minimising the fall distance.
Fall Factor 1:
- Anchor point is at shoulder or waist height, leading to a fall distance equal to the length of the lanyard or rope.
Fall Factor 2:
- Anchor point is below the worker's feet, causing a fall distance twice the length of the lanyard or rope.
What is fall clearance?
The fall clearance is the total vertical distance a worker could fall before being stopped by a fall arrest system. Calculating this distance is essential to prevent injuries caused by ground impact or collisions with structures.
Factors to Consider in Fall Distance:
- Free Fall Distance: How far the worker falls before the fall arrest system engages.
- Deceleration Distance: The additional distance required for the fall arrest system, such as an energy absorber, to arrest the fall safely.
- Rope or Lanyard Stretch: Dynamic elongation under force.
- Safety Clearance: The minimum distance below the worker to prevent contact with the ground or obstacles.
Example Calculation:
- Free fall distance: 2m lanyard, anchor at foot level → 4m free fall.
- Deceleration distance: 1m (energy absorber elongation).
- Safety clearance: 1m (to avoid contact with the ground).
- Total Fall Distance: 4m + 1m + 1m = 6m
Reducing Fall Risks
To ensure maximum safety:
- Always position the anchor point above the worker to reduce the fall factor.
- Use energy-absorbing lanyards to minimise the force during fall arrest.
- Calculate and ensure adequate fall clearance to prevent ground impact.
- Regularly inspect all fall protection equipment for wear or damage.