This calculator checks whether a fall arrest system stops a worker before they hit the level below. It handles lanyards and self-retracting lifelines, anchors overhead, at D-ring height or at foot level, swing falls and horizontal lifelines, and it draws the fall to scale so you can see where the worker stops.
The clearance stack
- Free fall: the lanyard length less the anchor's height above the D-ring. Anchored below the D-ring, it adds.
- Deceleration: how far the energy absorber tears out, or the SRL's arrest distance. Use the figure on the label.
- Harness stretch and D-ring slide: about 1.5 ft (0.45 m) together.
- D-ring to feet: about 5 ft (1.5 m) for most workers.
- Safety margin: 2 ft (0.6 m) is common; many programs use 3 ft (0.9 m).
The clearance needed below the working surface is the total, less the D-ring's height. Compare it with the distance to the ground, the next level, or the first thing the worker could hit, whichever is closest.
Swing falls
Whatever the connector, a worker who falls ends up directly below the anchor. With a lanyard, an offset anchor shortens the free fall but swings the worker sideways into whatever is there. With an SRL, the line has already paid out to the worker's position, so the swing adds to the drop: the calculator works that out from the true line length, and checks it against Alberta's 1.2 m limit.
Across Canada
Pick your jurisdiction in the calculator and it checks the free fall and swing against that jurisdiction's limits and lists its rules. In brief:
| Jurisdiction | Fall protection from | Free fall | Arrest force |
|---|---|---|---|
| Alberta | 3 m (1.2 m at permanent work areas) | 1.2 m without an absorber | Arrest force at most 6 kN, or 8 kN with an E6 absorber |
| British Columbia | 3 m | 1.2 m without an absorber, 2 m with one | Arrest force at most 8 kN |
| Saskatchewan | 3 m | 1.2 m without an absorber, 2 m with one | Arrest force at most 8 kN |
| Manitoba | 3 m | 1.2 m without an absorber | Arrest force at most 8 kN |
| Ontario | 3 m | Per CSA and the maker | Arrest force at most 8 kN |
| Quebec | 3 m | 1.8 m with one | Arrest force at most 6 kN |
| New Brunswick | 3 m | 1.2 m without an absorber, 1.8 m with one | Arrest force at most 8 kN |
| Nova Scotia | 3 m | 1.22 m without an absorber | Arrest force at most 8 kN |
| Prince Edward Island | 3 m | 1.22 m without an absorber | Free fall over 1.22 m needs an absorber that keeps the shock under 4 kN |
| Newfoundland and Labrador | 3 m | 1.22 m without an absorber | Free fall over 1.22 m needs an absorber that keeps the shock under 4 kN |
| Federal (Canada Labour Code) | 3 m | Per CSA and the maker | Per CSA |
| Yukon | 3 m | 1.2 m without an absorber | Per CSA |
| Northwest Territories | 3 m | 1.2 m without an absorber, 2 m with one | Arrest force at most 8 kN |
| Nunavut | 3 m | 1.2 m without an absorber, 2 m with one | Arrest force at most 8 kN |
In Alberta
Part 9 of Alberta's OHS Code requires fall protection from 3 m, a written fall protection plan where workers use fall arrest, anchors rated for 16 kN per worker (or twice the maximum arrest force where an engineer designs them), and a rescue plan. Our on-site safety management and training services help crews plan it, and the COR readiness check shows where the rest of your program stands.
Sources: Alberta OHS Code (AR 191/2021), Part 9; CSA Z259.11-17 and Z259.2.2-17; ANSI/ASSP Z359.13 (48 in maximum deployment for 6 ft free-fall absorbers) and Z359.14-2021 (Class 1 SRL arrest distance under 42 in); fall protection makers' clearance charts (Guardian, 3M) for harness stretch, safety margins and 12 ft lanyard deployment.