Calculate peak arrest force and anchor design load for fall arrest systems per AS/NZS 1891.4.
Include tools and PPE
Peak Arrest Force
2.37 kN
AS/NZS 1891.4 Limit
6.0 kN
Anchor Design Load
4.74 kN
Within 6 kN arrest force limit
Anchor design load = 2 × peak arrest force × number of workers (AS/NZS 1891.4). This tool is for guidance only — all fall protection systems must be designed by a competent person.
Under AS/NZS 1891.4, a static anchor point for a single user must be rated to withstand at least 12 kN (approximately 1200 kg). For engineered anchor systems, the design load is 2 × the peak arrest force per attached user. The maximum allowable arrest force on a worker is 6 kN.
Fall factor is the ratio of fall distance to the length of the lanyard. A fall factor of 1 means you fall the full length of the lanyard. A fall factor of 2 (worst case) occurs when the anchor is below your feet and you fall twice the lanyard length. Higher fall factors generate higher arrest forces.
An energy absorber (shock-absorbing lanyard) is required when the calculated peak arrest force would exceed 6 kN without one. For heavier workers (>100 kg) or fall factors above 0.5, an energy absorber is strongly recommended to keep arrest forces within safe limits.