What is the hierarchy of control for working at height?

Three steps, in this order. Avoid work at height where it is reasonably practicable to do the work safely otherwise than at height. Prevent falls, using an existing place of work that complies with Schedule 1 or, failing that, the right work equipment. Minimise the distance and consequences of a fall where the risk of one has not been eliminated. The order comes from regulation 6 of the Work at Height Regulations 2005.

Is the avoid, prevent, minimise order law or just guidance?

It is law. Regulation 6 of the Work at Height Regulations 2005, SI 2005/735, is headed Avoidance of risks from work at height and sets the three steps out as duties on every employer. HSE publishes guidance explaining it, including the brief guide INDG401, but the order itself is statutory rather than advisory.

Is there a minimum height before the Regulations apply?

No. Regulation 2 defines work at height as work in any place, including a place at or below ground level, where a person could fall a distance liable to cause personal injury if the measures required by the Regulations were not taken. There is no threshold in the definition, so working alongside an open excavation or a service pit is caught by it.

What is the difference between fall prevention and fall arrest?

Prevention stops the fall happening and sits at step two. Arrest accepts that a fall may happen and limits what it does to you, which is step three. A harness can be rigged either way: as work restraint, with the lanyard short enough that the wearer cannot reach the edge, it prevents a fall; as fall arrest, the fall occurs and the system stops it.

Working at Height Hierarchy of Control

Published 2 August 2026

On a UK construction site the order in which you deal with a fall risk is not left to judgement. Regulation 6 of the Work at Height Regulations 2005 fixes it: avoid, then prevent, then minimise. The CITB HS&E test you sit for your CSCS card asks that in a dozen different costumes, and it is nearly always checking that you reach for the right step first.

The three steps, in the order the law sets them

Each step is reached only when the one above it has genuinely been ruled out. You do not skip to a harness because it is quicker to fit than a scaffold.

Step	What it looks like on a UK site
1. Avoid the work at heightreg 6(2): do it safely from the ground instead, where that is reasonably practicable	Build a roof truss or a plant skid at ground level and lift it in; clear a gutter or change a lamp with a long-reach pole; specify equipment serviceable from the ground
2. Prevent the fallreg 6(3) and 6(4): use an existing place of work that complies with Schedule 1, or the right work equipment	A scaffold with guard rails and toe boards; a fully boarded mobile tower; a MEWP; a flat roof with a permanent parapet; fixed covers over openings and fragile roof lights
3. Minimise distance and consequencesreg 6(5): only where the risk of a fall has not been eliminated	Safety nets or soft landing systems rigged close beneath the work; an airbag deck; a harness and lanyard anchored so the fall distance is as short as it can be, with a rescue plan

The exam point: collective beats personal

Regulation 6 sets the order of the steps. Regulation 7 governs what you reach for inside a step, and its first instruction is the one the test keeps asking about: an employer selecting work equipment for use in work at height must “give collective protection measures priority over personal protection measures”.

A guard rail, a boarded tower platform or a safety net protects everyone in the area whether they are thinking about it or not. A harness protects the one person wearing it. That is the reasoning that also puts types of PPE last in the general hierarchy of controls. If one option removes the risk for the whole gang and another protects a single worker, the first is almost always right.

What regulation 6 actually says

Regulation 6 of SI 2005/735 is headed Avoidance of risks from work at height, and its paragraphs read in order are the hierarchy. Paragraph 6(1) starts it from the risk assessment: every employer must take account of one made under regulation 3 of the Management Regulations when identifying the measures.

6(2)requires every employer to ensure that work is not carried out at height “where it is reasonably practicable to carry out the work safely otherwise than at height”.
6(3) and 6(4)require, where work is carried out at height, “suitable and sufficient measures to prevent, so far as is reasonably practicable, any person falling a distance liable to cause personal injury”. Those measures are working from an existing place of work, or existing means of access and egress, which complies with Schedule 1 where that is reasonably practicable to do safely and under appropriate ergonomic conditions; and where it is not, providing “sufficient work equipment for preventing, so far as is reasonably practicable, a fall occurring”.
6(5)applies where those measures do not eliminate the risk of a fall. The employer must then provide sufficient work equipment to minimise “the distance and consequences” of a fall, or, where minimising the distance is not reasonably practicable, the consequences alone, and must add training and instruction or other suitable and sufficient measures on top.

Note how often “so far as is reasonably practicable” appears. That phrase is what lets a step be ruled out, and it means the cost and effort would be grossly disproportionate to the risk, not that somebody found the step inconvenient.

Two things that catch people out

There is no trigger height.Regulation 2 defines work at height as work in any place, “including a place at or below ground level”, where a person could fall a distance liable to cause personal injury if the measures required by the Regulations were not taken. Getting to and from that place counts too, except by a staircase in a permanent workplace. Working alongside an open trench is work at height, which is why it overlaps with excavations and confined spaces.
A harness is not automatically step three. Regulation 2 groups work restraint, work positioning, fall arrest and rescue systems together as personal fall protection systems. Rigged as restraint, with the lanyard too short for the wearer to reach the edge, a harness prevents the fall and sits at step two. Rigged for arrest, the fall happens and the kit limits the damage, which is step three. Either way regulation 7 makes you consider the need for easy and timely evacuation and rescue, so hanging in a harness is not the end of the plan.

Who carries the duty

HSE states the purpose of the Regulations plainly: to prevent death and injury caused by a fall from height. They apply to employers and to anyone who controls work at height, facilities managers and building owners who contract others to work at height being HSE's examples of the second group. Those in control must first assess the risks, then make sure the work is properly planned, supervised and carried out by competent people, including using the right type of equipment. Low-risk, relatively straightforward tasks require less effort when it comes to planning. Employees are not bystanders either: they must take reasonable care of themselves and of others who may be affected by their actions, and co-operate with their employer. What has to be reported to HSE after a fall is a separate subject, covered under RIDDOR. HSE's own summary is the brief guide INDG401, “Working at height: A brief guide”.

Practise the working at height questions

Height questions turn up across the Operatives paper, not only in their own section, because falls are a risk on roofs, on demolition and around excavations alike. Work through the CSCS working at height questions, try the CSCS demolition questions for the same hierarchy in a different setting, or browse every CSCS test question and answer set. If height is your trade rather than an occasional job, the CSCS specialist work at height test goes further than the core paper. For a timed run, sit a free CSCS practice test.

Working at height questions Full 50-question mock

Verified August 2026. The three steps and their wording were read from regulation 6, the collective before personal rule from regulation 7 and the definition of work at height from regulation 2, all of the Work at Height Regulations 2005 (SI 2005/735) on legislation.gov.uk. The purpose of the Regulations, who they apply to, the planning and competence duties, the employee duties and the reference to INDG401 come from the Work at Height law page on hse.gov.uk. No dimension from the Schedules and no figure from an HSE diagram is quoted here.

Working at height hierarchy of control: common questions

What is the hierarchy of control for working at height?: Three steps, in this order. Avoid work at height where it is reasonably practicable to do the work safely otherwise than at height. Prevent falls, using an existing place of work that complies with Schedule 1 or, failing that, the right work equipment. Minimise the distance and consequences of a fall where the risk of one has not been eliminated. The order comes from regulation 6 of the Work at Height Regulations 2005.
Is the avoid, prevent, minimise order law or just guidance?: It is law. Regulation 6 of the Work at Height Regulations 2005, SI 2005/735, is headed Avoidance of risks from work at height and sets the three steps out as duties on every employer. HSE publishes guidance explaining it, including the brief guide INDG401, but the order itself is statutory rather than advisory.
Why does a guard rail rank above a harness?: Because a guard rail is a collective measure and a harness is a personal one. Regulation 7 requires an employer selecting work equipment for work at height to give collective protection measures priority over personal protection measures. A guard rail, a boarded tower platform or a net protects everyone in the area without anyone having to do anything. A harness protects one person, and only if it is worn, clipped on and anchored properly.
Is there a minimum height before the Regulations apply?: No. Regulation 2 defines work at height as work in any place, including a place at or below ground level, where a person could fall a distance liable to cause personal injury if the measures required by the Regulations were not taken. There is no threshold in the definition, so working alongside an open excavation or a service pit is caught by it.
What is the difference between fall prevention and fall arrest?: Prevention stops the fall happening and sits at step two. Arrest accepts that a fall may happen and limits what it does to you, which is step three. A harness can be rigged either way: as work restraint, with the lanyard short enough that the wearer cannot reach the edge, it prevents a fall; as fall arrest, the fall occurs and the system stops it.
Who has legal duties for work at height?: Employers and anyone who controls work at height, which HSE illustrates with facilities managers and building owners who contract others to work at height. They must assess the risks first and make sure the work is properly planned, supervised and carried out by competent people, including using the right type of equipment. Employees have general duties to take reasonable care of themselves and others affected by their actions, and to co-operate with their employer.