Working at Heights:
A Complete Risk Assessment Guide
Falls from height remain one of the leading causes of workplace fatalities and serious injuries across the construction, facilities management, utilities, and logistics sectors. For every organisation that requires personnel to work above ground level — whether on a rooftop, a scaffold, a ladder, or an elevated work platform — a thorough, documented, and actively implemented working at heights risk assessment is not optional. It is a fundamental legal obligation and a direct determinant of whether workers go home safely at the end of every shift.
This guide is written for safety managers, facilities teams, construction supervisors, and compliance officers responsible for managing elevated work activities. It provides a structured, practical framework aligned with internationally recognised standards, covering the identification of key hazards, the application of the hierarchy of controls, task-specific risk considerations, emergency planning, and the competency requirements your workforce must meet before stepping foot above ground level.
By the end of this post you will have a clear, actionable understanding of how to build, implement, and review a working at heights risk assessment that genuinely protects your people and satisfies your regulatory obligations.
What Is a Working at Heights Risk Assessment?
A working at heights risk assessment is a systematic evaluation of any task in which a person could fall a distance liable to cause personal injury. This definition is deliberately broad: it encompasses work on roofs, scaffolding, access towers, mobile elevated work platforms (MEWPs), ladders, floor openings, fragile surfaces, and even work near excavations or open water at ground level where a fall could cause harm.
The assessment must be conducted before elevated work commences, must be site- and task-specific, must be carried out (or verified) by a competent person, and must inform every operational decision from equipment selection to emergency rescue planning. Generic or "copy-and-paste" assessments that are not tailored to the actual conditions of the work are a legal and operational liability.
Under the ILO Safety and Health in Construction Convention (No. 167) and its accompanying Recommendation (No. 175), employers have a primary duty to identify, assess, and control all risks associated with work at height. Nationally, this is typically codified through dedicated height safety regulations — such as the UK Work at Height Regulations 2005 — which require employers to avoid working at height where possible, use work equipment or other measures to prevent falls, and, where falls cannot be prevented, use equipment or measures to minimise fall distance and consequences. Non-compliance can result in regulatory enforcement action, civil liability, and — most critically — preventable loss of life.
Key Hazards
A. Hazards Arising from the Work Environment
- Unprotected edges and openings: Flat roofs, mezzanine floors, floor voids, and leading edges without adequate edge protection create immediate fall risk.
- Fragile or unstable surfaces: Fibre cement roofing sheets, corroded metal decking, rooflights, and wet or icy surfaces can fail unexpectedly under foot loading.
- Environmental conditions: High winds, rain, ice, reduced visibility, and extreme temperatures compromise both worker performance and the integrity of access equipment.
- Overhead hazards: Power lines, roof-mounted plant, and protruding structural elements present secondary strike and electrocution risks during elevated work.
- Inadequate access routes: Poor walkway design, missing handrails, or non-compliant ladder access increases the risk of slips, trips, and falls during approach and egress.
B. Hazards Arising from Equipment and Human Factors
- Incorrect selection of access equipment: Using a leaning ladder for sustained work, or a MEWP on uneven ground without stabilisers deployed, introduces avoidable risk.
- Uninspected or defective equipment: Scaffold boards with visible defects, harnesses past their service life, and ladders with damaged stiles are common precursors to fatal accidents.
- Falling objects: Tools, materials, and debris dropped from height create significant strike risk to people working or passing below.
- Fatigue and distraction: Physical tiredness reduces balance, grip strength, and decision-making quality — all critical at elevation. Rushing to complete tasks before weather changes is a recurrent behavioural risk factor.
- Lone working at height: Removes the immediate ability to raise an alarm or receive assistance in the event of a fall, suspension, or sudden incapacitation.
The 5-Step Risk Assessment Process
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1
Identify the Hazards
Conduct a pre-work site walk at the actual location where elevated activity will occur. Document every surface that may be walked on or worked near, all unprotected edges and openings, overhead services, prevailing ground conditions, and weather exposure. For example: "Flat bituminous felt roof — edge unguarded on north and west elevations; two rooflights present without covers; metal ladder access from south courtyard."
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2
Determine Who May Be Harmed and How
Identify all persons at risk — not only the operatives working at height but also those working or passing below, members of the public, and rescue personnel who may need to access the area in an emergency. Consider third-party contractors sharing the site and any vulnerable groups (trainees, agency workers, workers with medical conditions affecting balance or grip).
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3
Evaluate the Risks and Decide on Precautions
Rate each hazard for likelihood and severity, then cross-reference with available control options. A risk matrix should inform but not replace professional judgement. Ask: can this task be eliminated or done from ground level? If not, what collective protection (barriers, nets, MEWP) is applicable before considering personal protection (harness, lanyard)?
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4
Record Your Findings and Implement Controls
Document all identified hazards, the persons at risk, control measures selected, equipment to be used, site-specific safe working procedures, and the name of the responsible person. This record must be made available to all persons involved in the work before it starts — not filed away in a site office.
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5
Review and Update the Assessment
Review the assessment if conditions change (weather deterioration, structural discovery, near-miss event, scope change), at the end of each phase of work, and at defined intervals. For ongoing elevated maintenance contracts, monthly review cycles are recommended as a minimum, with immediate review triggered by any incident at height.
Hierarchy of Controls
The hierarchy of controls must be applied in strict order — exhausting higher-order options before descending to lower-order ones. The following table applies each level specifically to working at heights scenarios.
| Level | Control Measure | Priority |
|---|---|---|
| Eliminate | Redesign the task to remove the need to work at height entirely. Use telescopic tools, drones for inspection, or ground-based remote monitoring systems. Example: inspect roof drainage via CCTV camera drone rather than sending a worker onto the roof. | HIGHEST |
| Substitute | Replace a high-risk method of access with a lower-risk alternative. Replace a portable leaning ladder with an aluminium podium step platform; replace scaffolding on a fragile roof with a suspended access system to avoid surface loading. | HIGH |
| Engineering | Install permanent or temporary physical safeguards: edge protection barriers, guardrails, crash decks, safety nets beneath fragile surfaces, covered or plated floor openings, and MEWP guardrail systems with interlocked access gates. | MEDIUM |
| Administrative | Implement safe systems of work: permit-to-work procedures for roof access, toolbox talks before elevated tasks, exclusion zones below overhead work with barriers and signage, buddy systems for elevated lone working, weather-hold procedures triggered by wind speed thresholds. | MEDIUM |
| PPE | Provide and enforce the use of appropriately selected and inspected personal protective equipment: fall arrest harnesses with energy-absorbing lanyards or inertia reels, hard hats, non-slip safety footwear, and hand protection. Ensure anchor points are rated, positioned, and used correctly. | LAST RESORT |
PPE must only be relied upon when all higher-order controls have been genuinely considered and exhausted. A harness does not prevent a fall — it arrests one, and only if the anchor, lanyard geometry, and rescue plan are all correct. Selecting PPE as a first response rather than a last resort is a critical failure of the risk management process and will not satisfy regulatory inspection or legal scrutiny.
Specific Risk Considerations
Roof Work and Fragile Surface Access
Work on pitched or flat roofs involves the combined risks of surface instability, exposed edges, rooflights, and variable surface load capacity. All roof areas must be surveyed before access to determine surface material, structural condition, and rooflight locations. Roof boards and crawling boards must be used on pitched or fragile surfaces; no-go zones must be established around rooflights unless covers rated to 1.1 kN/m² are in place. Edge protection must be installed before work commences — not while it is in progress.
Scaffolding and Temporary Access Structures
Scaffold structures must be designed, erected, altered, and dismantled only by persons holding a recognised scaffold inspection qualification. Independent tied scaffolds, birdcage scaffolds, and system scaffolds must all be inspected by a competent person before first use, after any event that may have affected structural integrity (high winds, vehicle strike), and at minimum seven-day intervals during use. Written handover records must be retained on site. Never permit work on scaffold that has not been formally handed over and documented as safe.
Mobile Elevated Work Platforms (MEWPs)
MEWPs offer significant productivity advantages over scaffolding for short-duration elevated tasks, but introduce their own risk profile: ground bearing capacity, overhead power lines, outrigger deployment on slopes, basket overloading, and entrapment hazard at the platform head. Before use, the operator must conduct a MEWP-specific risk assessment, verify ground conditions, conduct a pre-use inspection against the manufacturer's checklist, and establish an exclusion zone around the machine. Operators must hold evidence of current IPAF or equivalent training.
Ladder and Stepladder Use
Ladders and stepladders are legitimate access tools for short-duration, low-risk tasks where other access equipment is not reasonably practicable. They are not suitable for tasks requiring both hands, tasks lasting more than 30 minutes at the elevated position, or work above 9 metres. The assessment must justify ladder use specifically and document the conditions: three points of contact maintained, correct angle (75° for leaning ladders), tied or footed, on firm level ground, and with an exclusion zone to prevent disturbance from below.
Emergency and Rescue Planning
A working at heights risk assessment is incomplete without an accompanying emergency rescue plan. The plan must be site- and task-specific, communicated to all persons involved in the work before it starts, and practically tested — not simply filed as a document. Suspension trauma (orthostatic shock) can render a person unconscious within minutes of hanging in a harness following an arrested fall; rescue must therefore be achievable within minutes, not hours.
- Define the rescue method: Self-rescue, assisted rescue (colleague using a rescue kit), MEWP-assisted rescue, or emergency services. The method must be realistic and achievable at the specific work location.
- Equip the site: Rescue kits — including descent devices, rescue lanyards, and first aid provisions — must be physically present on site before elevated work starts, not ordered when needed.
- Train the rescue team: At least one competent person capable of executing the rescue procedure must be present or immediately contactable throughout the elevated work activity.
- Establish communication: Lone workers at height must have a means of raising an alarm — radio, mobile phone with signal, or a monitoring check-in system — at all times.
- Brief emergency services: For complex elevated operations, notify local fire and rescue services in advance and provide site access information to reduce response time.
Training and Competency Requirements
Competency in working at heights is not conferred by awareness alone — it requires demonstrable knowledge, practical skill, and verified understanding of the specific equipment and environment in which the worker will operate. The following standards apply across most international jurisdictions and industry sectors.
- Working at Heights Awareness: Mandatory foundation training for all persons who may work at or near height. Covers risk identification, legal duties, equipment recognition, and emergency procedures.
- Harness & Fall Protection Equipment: Practical training in the selection, pre-use inspection, donning, adjustment, anchorage selection, and post-incident retirement of fall arrest and restraint systems. Renewal recommended every 3 years minimum.
- IPAF Operator Licence (or equivalent): Mandatory for all MEWP operators. Category-specific (1a/1b for scissor lifts; 3a/3b for boom platforms). Must be current and appropriate to the machine category being operated.
- PASMA Scaffold Inspection (or equivalent): For supervisors and operatives responsible for erecting, altering, or inspecting modular access towers. Mandatory inspection record-keeping follows certification.
- Rescue Training: At least one member of any elevated work team must hold current training in suspended casualty rescue and first aid at height.
- Medical Fitness: Workers performing tasks at height must be medically screened for conditions affecting balance, grip, or consciousness. Vertigo, epilepsy, and certain cardiac conditions must be assessed by occupational health before clearance is granted.
Applicable International Standards
- ILO C167 ILO Safety and Health in Construction Convention No. 167 — establishes primary employer duties for hazard identification and fall prevention in construction operations.
- ISO 45001 Occupational Health and Safety Management Systems — provides the framework for systematic risk assessment, control planning, and continual improvement across all work activities including elevated work.
- EN 363 Personal Fall Protection Equipment — Systems (European Standard) — specifies performance requirements for fall arrest, work positioning, and rope access systems.
- EN 1004 Mobile Access and Working Towers — Safety Requirements — governs the design, manufacture, and use of mobile modular access towers (aluminium scaffold towers).
- ISO 16368 Mobile Elevating Work Platforms — Design, Calculations, Safety Requirements, and Test Methods — international standard governing MEWP design and operational safety requirements.
- OHSAS 18001 Occupational Health and Safety Assessment Series — predecessor to ISO 45001; still referenced in many legacy management systems as the benchmark for OHS risk control frameworks.
- EN 1263 Safety Nets — Safety Requirements, Test Methods — specifies standards for fall arrest safety nets used as collective protection below elevated work areas.
Reviewing and Maintaining the Risk Assessment
A working at heights risk assessment is a living document, not a one-time administrative exercise. It must be reviewed and updated at regular intervals and immediately when any of the following trigger points occur.
- Change in scope or task: Any modification to the nature of the elevated work — new roofing materials, structural alterations, extension of working area — requires a full reassessment before work continues.
- After any incident or near miss: Incidents, dangerous occurrences, and near misses at height must trigger immediate review to identify whether the assessment adequately captured the risk and whether controls were effective.
- Seasonal and environmental changes: A risk assessment valid for summer conditions on a flat roof may not be adequate for the same roof in winter, when ice, low-angle sunlight reducing visibility, and increased wind loading alter the risk profile materially.
- Introduction of new equipment or technology: New access equipment, different harness systems, or updated rescue devices must be evaluated and incorporated into the assessment and associated training.
- Regulatory or standards update: When relevant legislation or international standards are revised, the assessment must be checked for alignment and updated accordingly.
- Periodic review: As a minimum, all working at heights risk assessments should be formally reviewed at least annually, even in the absence of other trigger events.
A completed working at heights risk assessment document is the beginning of your compliance obligation, not the end of it. Regulatory authorities and courts will look beyond the paperwork to ask whether controls were actually implemented, whether workers were genuinely trained and briefed, whether equipment was inspected on the day of use, and whether rescue plans were rehearsed and operable. Inspection, supervision, monitoring, and continuous improvement are what make a risk assessment real. Sign and file it by all means — but then go out and live it.
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