2.4 Work at Height Regulations 2005 (WAHR) & Hierarchy of Control

Scope and Statutory Definition Under WAHR 2005

The Work at Height Regulations 2005 (WAHR, Statutory Instrument 2005 No. 735) govern all work activities in Great Britain where there is a risk of a fall liable to cause personal injury. WAHR places clear statutory duties on employers, duty holders, self-employed contractors, and employees to plan, supervise, and execute work at height safely.

Dispelling the Myth of the "Two-Metre Rule"

A persistent and dangerous misconception in the construction and maintenance industries is that regulations only apply once a worker is elevated above 2 metres. Under older, repealed legislation (such as the Construction (Health, Safety and Welfare) Regulations 1996), a 2-metre threshold existed for certain scaffolding duties. However, WAHR 2005 completely abolished any minimum height threshold.

Under Regulation 2 of WAHR, work at height is legally defined as:

• Work in any place (including a place at, above, or below ground level);
• Obtaining access to or egress from such a place (except by a staircase in a permanent workplace);

where, if measures required by the regulations were not taken, a person could fall a distance liable to cause personal injury.

Consequently, standing on a 300 mm low-level platform, working next to an unguarded 1-metre inspection pit, or working from a 40-metre telescopic boom all constitute work at height under UK law. If a fall could result in injury, WAHR applies in full.

One 2-metre figure does survive: Regulation 12(4) requires a working platform used for construction work, from which a person could fall 2 metres or more, to have been inspected in position (or, for a mobile working platform, on the site) within the previous 7 days. That is an inspection rule, not a threshold for when the Regulations apply.

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Regulation 6: The Statutory Hierarchy of Control

Regulation 6 of WAHR sets out a mandatory, three-tier Hierarchy of Control that duty holders must systematically follow when planning work at height. Duty holders cannot jump straight to deploying a MEWP or putting on a fall arrest harness without first demonstrating that higher levels of the hierarchy are not reasonably practicable.

               ┌─────────────────────────────────────────┐
               │ Step 1: AVOID Work at Height            │
               │ - Design out the risk                   │
               │ - Ground-based reach-and-wash systems   │
               │ - Prefabricate assemblies at ground level│
               └────────────────────┬────────────────────┘
                                    │ Not Reasonably Practicable
                                    ▼
               ┌─────────────────────────────────────────┐
               │ Step 2: PREVENT Falls                   │
               │ - Use an existing safe place of work    │
               │ - Collective equipment: MEWPs, scaffolds│
               │ - Fully guarded working platforms       │
               └────────────────────┬────────────────────┘
                                    │ Cannot Completely Prevent Risk
                                    ▼
               ┌─────────────────────────────────────────┐
               │ Step 3: MINIMISE Distance & Consequences│
               │ - Collective: Safety nets, soft bags    │
               │ - Personal: Fall arrest systems, energy │
               │   absorbers, suspension rescue plan     │
               └─────────────────────────────────────────┘

Stage 1: Avoid Work at Height Where Reasonably Practicable

The primary legal duty is to eliminate height hazards entirely:

• Ground-Based Tooling: Utilising telescopic reach-and-wash water-fed poles for window cleaning, or ground-level pneumatic pole saws for tree maintenance.
• Design and Prefabrication: Assembling ventilation duct spools, pipe racks, or structural roof trusses at ground level, then lifting the completed assembly into place by crane, minimising the time workers spend at height.
• Remote Inspection: Deploying aerial drones or pole-mounted high-definition cameras for roof and structural surveys.

Stage 2: Prevent Falls (Where Work at Height Cannot Be Avoided)

Where working at height is unavoidable, the duty holder must select work equipment that prevents a fall before it can initiate:

• Existing Safe Place of Work: Operating from a permanent flat roof with adequate edge protection (for construction work, guard-rails of at least 950 mm).
• Collective Work Equipment: Deploying MEWPs (scissor lifts, boom platforms) or edge-protected mobile access towers. Within a MEWP platform, the complete enclosure of top rails, intermediate rails, and toe-boards physically prevents the operator from falling off the working deck.

Stage 3: Minimise the Distance and Consequences of a Fall

Where the risk of a fall cannot be completely eliminated by collective prevention:

• Collective Fall Mitigation: Rigging industrial safety netting or soft-landing airbags beneath the work zone to catch a falling worker, minimising the drop distance and absorbing deceleration kinetic energy.
• Personal Fall Protection: Equipping workers with personal fall arrest equipment (BS EN 361 full-body harness, energy-absorbing lanyard, and overhead anchor point). Personal fall arrest is the lowest tier on the hierarchy because it only activates after a fall has occurred, exposing the worker to dynamic arrest forces, suspension trauma, and requiring immediate rescue intervention.

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Collective Protection vs Personal Protection

Regulation 7 of WAHR establishes a clear statutory priority:

Duty holders must select work equipment that gives collective protection measures priority over personal protection measures.

Why Collective Protection Takes Precedence

In boom-type MEWPs, personal fall protection (a travel restraint lanyard) is used inside the platform specifically to prevent the occupant from being catapulted out of the basket. However, the MEWP guardrail framework remains the primary collective barrier preventing falls under normal operating conditions.

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Guard-Rail Requirements: WAHR Schedule 2 and the MEWP Design Standard

Regulation 8 of WAHR applies Schedule 2 to guard-rails, toe-boards, barriers and similar collective protection, and Schedule 3 to working platforms. Schedule 3 also requires the surface supporting a working platform to be stable and strong enough for it—a legal hook for the ground assessments covered in Chapter 7.

For construction work, Schedule 2 paragraph 3 sets three dimensions:

1. Top guard-rail: at least 950 mm above the edge from which a person could fall (910 mm is accepted only for protection already fixed before WAHR came into force).
2. Toe-boards: suitable and sufficient to prevent the fall of any person, material or object. WAHR does not give a toe-board height.
3. Intermediate guard-rail: positioned so that no gap between it and other protection exceeds 470 mm.

A MEWP basket is not designed to Schedule 2; it is built to the machinery standard BS EN 280-1:2022, which is stricter:

    ──────────────────────────────────────────────  Top guard-rail
                         ▲                          (at least 1.1 m above floor)
                         │
       Intermediate rail no more than 0.55 m
       from the top rail or the toe-board
                         ▼
    ══════════════════════════════════════════════  Intermediate rail
    ▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓  Toe-board (at least 0.15 m;
    ██████████████████████████████████████████████   may reduce to 0.1 m at access)
                Platform floor

• Access Gates and Drop-Bars: Platform entry gates must not open outwards. They return to the closed position automatically (self-closing and self-latching) or are interlocked, so an occupant leaning on an unlatched gate cannot fall through it.

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Weather and Environmental Restrictions (Regulation 4(3))

Regulation 4(3) of WAHR places a direct duty on employers:

"Every employer shall ensure that work at height is carried out only when the weather conditions do not jeopardise the health or safety of persons involved in the work."

Regulation 4(4) disapplies this only for the police, fire, ambulance or other emergency services acting in an emergency. Regulation 4(2) adds that planning must include planning for emergencies and rescue—the legal basis for the rescue plan covered in Section 9.3.

1. Wind

Outdoor-rated MEWPs are normally designed for a maximum wind speed of 12.5 m/s (28 mph, Beaufort Force 6) under BS EN 280-1; machines rated for indoor use only carry a 0 m/s rating. The machine's own rated maximum on its plate or in its manual is the limit. Wind speed can be up to 50% greater at 20 metres than at ground level, so it must be checked at platform height with an anemometer. Wind ratings, gusts, funnelling and the sail effect of panels are covered in detail in Section 8.1.

2. Ice, Snow, and Sub-Zero Temperatures

Ice and snow on platform floors create slip hazards; snow and ice also add unmeasured weight that uses up rated load, and very cold hydraulic oil makes controls sluggish. Clear the platform and follow the manufacturer's cold-weather instructions before elevating.

3. Thunderstorms and Lightning

An elevated MEWP is a tall metal structure. At the first sign of an approaching thunderstorm, lower the platform, stow the machine and move personnel to suitable shelter.