A fall arrest system only protects you if there is enough clearance below the anchor for the system to deploy before you hit a lower level. This calculator estimates the required fall clearance from your connector, deceleration distance, body height and safety margin, then checks it against the clearance you actually have (OSHA 1926.502 / ANSI Z359).
The fall clearance formula
Required Fall Clearance = free-fall distance + deceleration distance + worker height (D-ring to feet) + safety factor. For a 6 ft shock-absorbing lanyard anchored at D-ring height, that is typically 6 + 3.5 + 5 + 2–3 ≈ 16–18 ft. SRLs need far less because they limit free fall and deceleration.
| Component | Typical value |
|---|---|
| Free fall (shock lanyard) | up to 6 ft (OSHA limit) |
| Deceleration distance (shock pack) | 3.5 ft max |
| Worker height (D-ring to feet) | ~5 ft |
| Safety factor | 2–3 ft |
Shop fall protection
FAQ
Why does a 6 ft lanyard need ~18 ft of clearance?
Because the lanyard free fall, the shock pack’s deceleration distance, your own body length below the D-ring, and a safety margin all add up. Many serious injuries happen when workers tie off with a lanyard at low heights where the system cannot fully deploy.
Do SRLs need less clearance?
Yes. A self-retracting lifeline limits free fall (often to ~2 ft) and decelerates over a short distance, so required clearance is much smaller — check the SRL label for its specific arrest distance.
Where should I anchor?
Overhead anchorage (above the D-ring) reduces free fall and swing-fall hazards. Follow the manufacturer’s instructions and your competent person’s plan.
Educational estimate only. Actual clearance requirements depend on the specific lanyard/SRL arrest distance, anchorage location, swing fall, and connector geometry on the manufacturer’s label. Fall protection must be designed and inspected by a qualified/competent person per OSHA 29 CFR 1926.502 and ANSI Z359.
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