A fall-arrest system may only be used where there is adequate fall clearance for it to work (Section 7), and anchorages are placed so users do not strike lower obstructions. Free fall is limited to 600 mm for limited free fall systems and 2 m for free fall systems (Table 2.1, clause 8.1); required clearance is estimated from free fall, energy absorber extension, the user's height below the attachment and a safety margin (a held supplier guide restates this as free fall plus absorber extension plus 1000 mm); climbing above the anchorage adds to free fall and should be avoided. Section 8 shows how equipment configuration (fixed length lanyards, type 2 and 3 fall-arrest devices) affects free fall distance.
The graph holds this control, the 0 it maps to, and the evidence behind each claim, over MCP and REST.