Fall distance and slack: the numbers the codes set

This page reports what the named codes, regulators and makers say. It is not training and does not teach the work. This page reports what the official source says. It is not legal advice: ask the office named here. Every source below was read on October 9, 2026. The site also has a fall factor tool that works from the visitor's own numbers. Where the climber ties in is covered in tie-in and second attachment rules.

Credits: SafeWork NSW text is adapted from the Tree works code of practice (March 2026), copyright State of New South Wales (SafeWork NSW), licensed under Creative Commons Attribution 4.0; changes were made, because the text is summarised and reworded. WorkSafe New Zealand material is summarised from its Approved Code of Practice for Safety and Health in Arboriculture, with the source acknowledged.

The numbers, source by source

Source	What it says
ICoP, United Kingdom, 3.8.6	The ICoP says the primary system should not allow a potential fall distance above 500 mm, and that the backup uses an anchor independent of the primary one where possible.
SafeWork NSW code, 4.9 and 4.4	When a climbing rope is part of the system, the code says the rope is kept taut to limit a fall to 600 mm or less. It says a work positioning harness is not for a free fall of more than 600 mm. It lists stopper and barrel knots as examples of knots that are not used.
WorkSafe NZ code, 3.2.2	No more than 0.5 metres of slack in the climbing line at any time. Supplementary anchors where a fall or swing is possible.
OSHA 1910.140(d)(1) and (d)(2)(ii), United States	A personal fall arrest system limits the arresting force to 1,800 pounds (8 kN), the deceleration distance to 3.5 feet (1.1 m) and the free fall to 6 feet (1.8 m).
OSHA 1910.140(e), United States	Positioning systems are tested by a drop of 4 feet with a 250 pound weight.
Ireland, S.I. 299/2007 regulation 112	Fall arrest needs a clear zone so that a worker does not hit the structure by pendulum effect.

How the figures relate

The three tree-specific codes work in fractions of a metre: 500 mm for the ICoP, 600 mm for NSW and 0.5 m of slack for New Zealand. The OSHA figures are for general fall arrest equipment and are larger, 6 feet of free fall against about 2 feet in the tree-specific codes. They are different kinds of limit: the OSHA numbers are the design limits of arrest equipment, while the tree-specific numbers are working limits on how much the climber may be allowed to drop at all.

Anchors and force

OSHA 1910.140(c)(13) sets the anchorage at 5,000 pounds (22.2 kN) per worker, or designed by a qualified person with a safety factor of two. The ICoP sets minimum breaking strengths of 18 kN for a temporary anchor device, 22 kN for connectors, 15 kN for a rope with termination and 22 kN without, and 15 kN for a lanyard. WorkSafe New Zealand asks for 22 kN kit, with friction hitch cord at least 70 percent of the diameter of the line. Under 1910.140(c)(17), equipment that has been impact loaded is removed from service.

What the sources leave out

HSE's climbing page, California's section 3427 and WorkSafeBC Part 26 give no distance figures for tree climbing, so no row is shown for them.