What is Working at Heights?

Understanding the Definition

Working at heights is a functional definition under Australian Work Health and Safety legislation. It's characterised by the potential energy involved in a fall from one level to another that is reasonably likely to cause injury. This definition deliberately avoids a universal minimum height for general duty of care, acknowledging that serious injuries and fatalities occur from low heights such as falls from trucks, ladders, or even kerbs.

Your primary duty of care under the WHS Act extends to all heights where a fall risk exists, regardless of the distance. However, specific regulatory triggers exist to mandate higher-order administrative controls.

In most Australian jurisdictions (NSW, Victoria, WA, ACT, NT, Tasmania), work involving a risk of a fall greater than 2 metres is classified as "high-risk construction work," legally requiring a Safe Work Method Statement. Queensland maintains a distinction: 3 metres for housing construction, 2 metres for other construction work.

South Australia is transitioning to national alignment. From July 1, 2026, SA will adopt the 2-metre threshold for high-risk construction work, replacing its previous framework.

The Statistical Reality

Safe Work Australia data consistently ranks falls from heights as a leading mechanism of injury and fatality across Australian workplaces. The risks are exacerbated by environmental factors—wind, rain, unstable surfaces—and human factors like fatigue and complacency.

The economic burden is substantial. South Australia alone recorded 1,585 workers' compensation claims for fall-related injuries since 2016/17. This underscores the business case for robust prevention strategies beyond moral and legal imperatives.

Accident investigations reveal a consistent pattern: organisations gravitate toward cheaper solutions like procedures and personal protective equipment instead of eliminating the hazard or implementing engineering controls. This is precisely why the hierarchy of controls is legally mandated, not merely suggested.

The Mandated Hierarchy for Heights Work

The WHS Regulations (Part 4.4) require you to work systematically through the hierarchy of controls. You cannot legally justify using fall arrest systems or administrative controls unless you can demonstrate that higher-order controls were genuinely evaluated and found not reasonably practicable.

Level 1: Elimination

The most effective control removes the hazard entirely. This is often achieved during design or planning. Installing air conditioning units at ground level rather than on roofs, using tilt-slab construction where walls are built on the ground and lifted, or using long-handled tools for cleaning windows from ground level all eliminate the need to work at height.

If elimination is reasonably practicable, you must do it. Cost is a factor but must be grossly disproportionate to the risk to justify ignoring elimination.

Level 2: Passive Fall Prevention

If elimination is impossible, you must perform the work from solid construction or using passive fall prevention devices. These controls protect workers without requiring active input like clipping on a lanyard.

Solid construction means a structural area with a flat, stable surface capable of supporting workers and materials, protected by perimeter barriers—think permanent balconies or walkways with guardrails.

Passive devices include properly erected scaffolding with guardrails, mid-rails, and toe-boards; Elevating Work Platforms (EWPs) like scissor lifts and boom lifts; and temporary perimeter guardrails installed on roof edges.

Passive controls are superior because they don't rely on worker behaviour or correct PPE use. They protect everyone in the area, not just the individual worker, and remain effective even when workers are tired, distracted, or untrained.

Level 3: Work Positioning (Restraint)

Travel restraint systems prevent workers from reaching positions where falls could occur. A harness and lanyard connect to an anchor, with the lanyard length shorter than the distance to the edge.

Because the worker physically cannot reach the fall hazard, no fall energy is generated. This eliminates the risk of impact injury and suspension trauma. However, it requires precise setup—if the lanyard is too long or the anchor moves, the system becomes a fall arrest system for which it may not be rated.

Level 4: Fall Arrest Systems

Fall arrest systems stop a fall that has already occurred. They're the least preferred engineering control because the fall event itself carries significant risks: equipment failure, hitting the structure during the fall, the pendulum effect, and suspension intolerance after the fall.

A complete system includes a full body harness, energy absorber (to limit force to less than 6kN), lanyard, and anchor rated to 15kN for single-person systems or 21kN for two-person systems.

Because risk remains high even with proper equipment, regulations mandate that you establish and test emergency rescue procedures before the work starts. Relying on emergency services who may take 20+ minutes to arrive is not a compliant strategy.

Level 5: Administrative Controls

Administrative controls rely entirely on human behaviour. Portable ladders are primarily for access/egress or very short-duration light work—they offer no structural fall protection. Procedures, signs, exclusion zones, and permits all fail instantly if a worker is fatigued, distracted, or rushed.

Use administrative controls only when higher-level controls are not reasonably practicable, and document why.

Technical Dynamics: Understanding Fall Physics

The Pendulum Effect

The "pendulum effect" or "swing fall" is a critical failure mode in fall arrest design. It occurs when your anchor point is not positioned directly overhead.

If you fall while moving laterally away from the anchor, gravity swings you back toward the vertical line of the anchor. You generate horizontal velocity and can strike obstacles, walls, or the ground with devastating force. A swing fall can cause severe injury even if you don't hit the ground.

Standard guidance suggests keeping the angle of the lanyard from the anchor within 30 degrees of vertical. Mitigation strategies include using mobile anchors on rail systems that follow the worker, diversion anchors to redirect the rope and keep the line perpendicular to the edge, or dual anchors to triangulate and restrict lateral movement.

Fall Clearance and Functional Length

Calculating "Minimum Clearance Required" is essential to prevent hitting the ground during the arrest phase. The calculation includes: Free Fall Distance + Deceleration Distance (energy absorber tear-out) + Height of User + Safety Margin (usually 1m).

The 2025 update to AS/NZS 1891.4 introduces "functional length"—the total length of the connecting system including lanyard, connectors, and fully deployed absorber. This precise definition forces you to account for every carabiner and the full extension of the absorber, which can be up to 1.75m.

A standard 2-metre lanyard with a deployed absorber can result in a drop of over 6 metres before you stop. If your work height is only 4 metres, a fall arrest system will fail—you'll hit the ground. In such cases, you must use a work positioning system, shorter lanyard, or select a different control higher in the hierarchy.

Anchorage Requirements

Anchors are the foundation of any fall protection system. A single-person fall arrest anchor must be rated to 15kN (approximately 1,500kg force). Two-person anchors require 21kN.

The structure itself—roof truss, concrete beam, steel column—must be capable of supporting this load. Attaching to decorative balustrades, pipework, or unverified structural elements is a common cause of catastrophic failure. If you're unsure whether a structure can support fall arrest loads, you must have it assessed by a qualified engineer.

Equipment Inspection and Maintenance

Equipment reliability depends on rigorous adherence to AS/NZS 1891.4 inspection schedules, though local regulations can impose stricter requirements.

Inspection Regimes

Pre-use check: You must inspect your equipment before every use. Check webbing for cuts, chemical burns, heat damage, or UV degradation; hardware for cracks, deformation, or corrosion; and labels for legibility.

Six-monthly inspection: A competent person specifically trained in height safety equipment inspection must formally inspect harnesses, lanyards, and associated equipment every 6 months. This inspection must be documented with records kept accessible.

Anchorage inspection: Drilled or friction anchors typically require inspection every 12 months. Chemical or glued anchors often require pull-testing to verify bond strength. South Australia has historically required 6-monthly inspections for permanently fixed anchorages, stricter than the national 12-month standard.

Retirement Criteria

Retire equipment immediately if it shows cuts in webbing greater than 1mm, chemical burns, heat damage (glazing or melting), UV degradation (powdering or significant fading), cracks or deformation in hardware, corrosion that impedes function, or illegible compliance labels.

Most manufacturers recommend a 10-year maximum life for webbing products even if they appear visually sound, due to invisible UV degradation. In Australia's high-UV environment, equipment left exposed can lose significant strength rapidly.

Suspension Intolerance: The Silent Killer

Suspension intolerance, also known as suspension trauma or orthostatic intolerance, is a life-threatening condition that occurs when a worker hangs motionless in a harness following a fall.

When upright and immobile, gravity causes blood to pool in the legs. Your leg muscles normally act as pumps returning blood to the heart, but they're inactive when suspended. This leads to rapid blood pressure drop and reduced blood flow to the brain.

Symptoms progress from faintness, nausea, sweating, and dizziness to loss of consciousness. Once unconscious, your airway may become obstructed, and loss of muscle tone exacerbates blood pooling, potentially leading to cardiac arrest within minutes.

The Lay Flat Protocol

For years, a dangerous myth persisted that laying a suspended worker flat after rescue would cause "reflow syndrome"—a sudden rush of toxic blood to the heart causing cardiac arrest. This led to harmful advice to keep patients seated or semi-recumbent.

The Australian Resuscitation Council (ANZCOR) has thoroughly reviewed the evidence and debunked this myth. There is no evidence that lying a patient flat is harmful. Conversely, keeping a hypotensive, unconscious patient upright is dangerous as it compromises blood flow to the brain.

ANZCOR Guideline 9.1.5 explicitly states: "Rest the responding person in a position of comfort, ideally lying down... Loosen or remove harness... Administer oxygen if available."

Immediate rescue is critical. Lay the victim flat, manage their airway using ABC protocols, and call 000 immediately.

Rescue Planning Requirements

Because suspension intolerance can be fatal in under 10-15 minutes, you must have a specific, tested rescue plan for your site before work begins. This is not optional—it's a legal requirement when using fall arrest systems.

Your rescue capability might involve an on-site rescue team, a crane with a man-box available immediately, or EWP access. Workers must be trained in the rescue procedure, including use of retrieval winches on inertia reels. Document your rescue plan and conduct practical drills to verify it works under realistic conditions.

Training and Competency

Under the WHS Act, you must ensure workers are trained to perform work at heights safely. RIIWHS204E "Work Safely at Heights" is the standard industry qualification in Australia, covering hazard identification, equipment selection, and practical use of systems.

While the Statement of Attainment doesn't technically expire, industry best practice and many Tier 1 contractor requirements dictate refresher training every 2 years. This ensures workers stay updated on regulatory changes and maintain familiarity with rescue techniques.

AS/NZS 1891.4:2025 has shifted focus from simply citing course codes to defining "Recommended training outcomes." This ensures training is relevant to the specific equipment used. A worker using a complex twin-rope access system needs different training outcomes than a worker using a simple travel restraint lanyard on a roof.

This performance-based approach places the onus on you as the employer to verify that training matches the risk profile of the work being performed.

Common Challenges and Failure Modes

The "Just a Quick Job" Mentality

The most common administrative failure is bypassing controls for tasks perceived as short or simple. Data shows many falls occur during "quick" maintenance tasks where workers felt setting up fall protection took longer than the job itself.

This highlights the need for passive controls (Level 2) that don't require individual setup time. A permanent scaffold or platform with guardrails protects every worker automatically, regardless of time pressure.

Misunderstanding Clearance Calculations

Workers often fail to account for energy absorber deployment. A 2m lanyard might look short, but in a fall, it extends significantly. If you're 3m above the ground, a fully deployed system (2m lanyard + 1.75m extension + 1.8m worker height) will result in ground impact.

Always calculate total functional length before selecting fall arrest equipment. If clearance is insufficient, you must use a different control method.

Incompatible Equipment

Mixing components from different manufacturers or standards—such as using a rock climbing harness for industrial fall arrest—can lead to system failure. Industrial harnesses are designed to orient your body correctly during a fall to minimise injury. Recreational gear is not rated for the same static and dynamic industrial loads.

Use only equipment certified to Australian Standards (AS/NZS 1891 series) and ensure all components in the system are compatible.

Safe Work Method Statements for Heights Work

For construction work where there's a risk of falling more than 2 metres (or 3 metres for housing in Queensland), a Safe Work Method Statement is legally required.

Your SWMS must clearly identify the high-risk activity, list specific hazards (e.g., "Fall from roof edge," "Unstable working surface"), describe control measures following the hierarchy, and explain how you'll monitor those controls.

Generic SWMS are a common compliance failure. The document must reflect actual site conditions: specific anchor locations, weather considerations, rescue procedures available on that site, and equipment being used. A template downloaded from the internet doesn't satisfy your legal obligations.

Section 47 of the WHS Act requires consultation with workers when developing SWMS. Workers often know why a planned control might fail in practice—for example, "That anchor point can't be reached safely from the access route." Involving workers ensures your selected controls are suitable and won't be routinely bypassed.

Permit to Work Systems

While not universally mandated by WHS Regulations like SWMS, Permit to Work systems represent best practice in high-reliability organisations such as mining, oil and gas, and energy sectors.

The permit acts as a formal authorisation layer, ensuring all prerequisites are verified by an authorised person before you enter the risk zone. Prerequisites include isolation of power, checking weather conditions, verifying rescue team availability, confirming anchor inspections are current, and ensuring all workers hold current height work qualifications.

In complex environments, a "Working at Heights Permit" often integrates with other permits like Confined Space or Hot Work, creating a comprehensive risk management framework for the task.

Stop Work Authority is the cultural bedrock supporting permit systems. Any individual, regardless of rank or experience, must feel empowered to halt operations if they believe conditions are unsafe—such as sudden high winds affecting EWP stability, equipment defects discovered during pre-use checks, or scope creep where the job extends into unassessed areas.