Hierarchy of Controls: How to Apply It in Your SWMS

The hierarchy of controls is a systematic framework for eliminating or reducing workplace hazards. It ranks control measures from most effective (elimination) to least effective (PPE), and it is embedded in every piece of WHS legislation in Australia. When you prepare a SWMS under the WHS Regulation 2025, you are legally required to identify control measures — and inspectors specifically check whether you have considered higher-order controls before defaulting to PPE.

The hierarchy exists because not all controls are created equal. A guardrail physically prevents a fall. A harness only arrests a fall after it is already happening. Training tells someone to be careful. And PPE is the last line of defence when everything else has failed. The hierarchy forces you to think about the problem from the top down: can I get rid of the hazard entirely? If not, can I replace it with something less dangerous? If not, can I put a physical barrier between the worker and the hazard?

This is not academic theory. Australian courts have repeatedly held that a PCBU that jumps straight to PPE without considering engineering or administrative controls has failed its primary duty of care. A SWMS that lists only PPE as the control for a high-consequence hazard is frequently cited in prosecution briefs as evidence of a fundamental failure to apply the hierarchy of controls. The hierarchy is not optional — it is the legal framework that underpins every control measure in your SWMS, and its application is tested every time a SWMS is reviewed by a regulator.

A competent SWMS builder tags each control with its hierarchy level — [Elimination], [Substitution], [Engineering], [Administrative], or [PPE] — so inspectors can see at a glance that the hierarchy has been applied properly and that PPE is not being used as a substitute for higher-order controls.

Elimination is the most effective control because it removes the hazard completely. No hazard means no risk. It is also the hardest to achieve on a construction site where the hazards are often inherent to the work itself — you cannot eliminate gravity, and you cannot build a high-rise without working at height. But elimination is more achievable than most tradies think when the question is asked seriously at the planning stage rather than after the method has already been chosen.

Here are real Australian construction examples.

Prefabricate wall panels on the ground instead of building them at height. The wall framing, insulation, and cladding are all installed at ground level where there is zero fall risk. A crane lifts the completed panel into position. The hazard of working at heights for that entire phase of construction is eliminated, not just controlled.

Use pre-cast concrete instead of in-situ pours. Pre-cast elements are manufactured in a factory with controlled conditions, overhead cranes, and engineered formwork. The on-site hazards of formwork collapse, manual handling of reinforcing steel, and concrete pump operation are all eliminated for the structural elements covered by the pre-cast.

Design out excavation by using above-ground drainage solutions. If the design allows surface drainage rather than underground pipes, you eliminate the excavation hazard entirely — no trench collapse risk, no underground services strike risk, no confined space risk inside the drainage run.

Use a long-reach tool from ground level instead of working at height. For single point-of-use tasks — changing a light bulb, testing a smoke alarm, painting a gable — a long-reach tool lets the worker stay on the ground. The height hazard is eliminated for that specific task even if it cannot be eliminated across the project.

The key question to ask at the planning stage: can the work be redesigned so the hazard does not exist? If the answer is yes, that is your first option. If the answer is no — and often it is no in construction — move to Level 2. In your SWMS, document that you considered elimination even if you could not achieve it. An inspector seeing "[Elimination] Not reasonably practicable — work requires access to existing roof structure at 8 metres" knows you have thought about it properly rather than simply skipped the question.

Substitution means swapping a hazardous material, process, or piece of equipment for a less hazardous alternative. The hazard still exists but it has been reduced in severity. Substitution is often combined with elimination where full elimination is not practicable for the whole job.

Construction examples from Australian sites.

Use water-based paints instead of solvent-based coatings. Solvent-based products contain volatile organic compounds that cause respiratory irritation, headaches, and long-term neurological damage. Water-based alternatives reduce VOC exposure substantially. The painting still needs to happen, but the chemical hazard profile is dramatically reduced.

Replace traditional abrasive disc cutting with diamond wire cutting on large concrete sections. Traditional cutting generates enormous amounts of respirable crystalline silica dust — a known carcinogen that causes silicosis. Diamond wire cutting generates significantly less airborne dust and can be combined with water suppression for near-zero dust exposure. Since the 1 July 2024 ban on engineered stone (which affects all Australian jurisdictions), substitution of cutting methods has also become the primary route for reducing silica exposure on related natural stone work.

Substitute a scissor lift for a ladder where the work is repetitive or above 2 metres. The work at height still occurs, but a scissor lift provides a stable, guarded platform instead of a two-point contact ladder. The fall risk is substantially reduced, and the residual risk can be managed with straightforward engineering and administrative controls on top.

Use mechanical lifting aids instead of manual handling for loads over 20 kilograms. A vacuum lifter for glass panels, a block grab for concrete blocks, a pipe trolley for drainage pipes. The load still needs to move, but the musculoskeletal hazard is substantially reduced and the cumulative load across a project phase drops with it.

Substitution works best when you can identify a direct replacement that serves the same functional purpose. It is less effective when the hazardous element is fundamental to the work — you cannot substitute electricity out of electrical work. In those cases, move to Level 3. In your SWMS, tag substitution controls with [Substitution] and briefly note what the original hazard was and why the substitute is less hazardous. This demonstrates genuine application of the hierarchy rather than incidental choice.

Engineering controls physically isolate workers from hazards. They do not rely on human behaviour — they work whether the worker is paying attention or not. That is why they sit above administrative controls and PPE in the hierarchy, and why regulators expect to see them heavily featured in any competent construction SWMS.

Construction examples.

Edge protection on scaffolding and elevated work areas. A guardrail system compliant with AS/NZS 4994.1 physically prevents a worker from falling over the edge. It does not require the worker to clip on, remember to check their harness, or follow a procedure. It just works, every time, for every worker who is inside the protected zone.

Lock-out/tag-out on electrical isolation points. When a circuit is locked out with a personal padlock under AS/NZS 4836, it cannot be re-energised until the lock is removed. The system physically prevents exposure to live conductors. It is not a sign that says "do not switch on" — it is a lock that prevents switching on, even by a worker who does not see the sign.

Trench shoring and benching for excavations. Hydraulic shores or trench boxes physically hold the excavation walls apart, preventing collapse regardless of soil conditions, vibration, or weather. Compare this to an administrative control like "monitor soil conditions" — monitoring tells you the wall is about to collapse but shoring prevents it from collapsing in the first place.

Local exhaust ventilation for welding fumes. An LEV system physically captures fumes at the source and extracts them from the breathing zone. It does not rely on the welder wearing a respirator correctly — it removes the contaminant before it reaches the worker.

Guarding on power tools and machinery. A blade guard on an angle grinder, a kickback brake on a chainsaw, a roll-over protection structure on a skid steer. These are engineered into the equipment and function automatically whenever the equipment is used.

Engineering controls are the workhorse of construction safety. Most well-written SWMS have more engineering controls than any other type. If your SWMS is heavy on PPE and light on engineering controls, an inspector will notice immediately and ask why higher-order controls were not considered or adopted.

Administrative controls change the way work is organised, supervised, or performed. They rely on human behaviour, which makes them less reliable than engineering controls — but they are essential in construction where engineering controls alone cannot address every hazard.

Construction examples.

Permit-to-work systems. A confined space entry permit requires gas testing, a standby person, an emergency rescue plan, and management sign-off before anyone enters a confined space. The permit does not physically prevent entry — but the process ensures all safety checks are completed before entry occurs and creates a clear audit trail afterwards.

Job rotation for repetitive tasks. Rotating bricklayers between laying, mixing, and clean-up every two hours reduces cumulative musculoskeletal load. The manual handling hazard still exists, but exposure duration is reduced and cumulative injury risk drops with it.

Training and competency verification. Ensuring every worker who operates a piece of powered mobile plant holds a valid High Risk Work Licence or equivalent competency is an administrative control. The licence does not make the equipment safer — it ensures the operator has been trained and assessed to use it safely. Common training codes include RIIWHS204E for working at heights, TLILIC0005 for dogging, CPCCLSF2001A for licensed scaffolder, and the state-issued HRWL qualifications for forklift, boom-type EWP, and slewing mobile crane operation.

Exclusion zones around mobile plant. Marking a 3-metre exclusion zone around a working excavator and enforcing it with a spotter prevents pedestrian strike. The zone relies on people respecting the boundary and the spotter doing their job — both human factors that can fail under time pressure or fatigue.

Toolbox talks and pre-start briefings. Walking the crew through the SWMS hazards and controls each morning ensures everyone understands the risks for that day's work. It is an administrative control because it relies on communication and comprehension — which is exactly why comprehension checks and direct questioning are part of a proper briefing.

Signage and barricading. Hazard warning signs, traffic management signage, asbestos removal warnings, and exclusion zone tape all delineate the boundaries of safe and unsafe areas. They rely on workers and visitors recognising and respecting them — reliable enough to be useful, but not engineered enough to guarantee protection.

Administrative controls are necessary but never sufficient on their own. They must be layered on top of engineering controls, not used instead of them. An inspector who sees a SWMS with only administrative controls and PPE will ask why no engineering controls were considered.

Personal Protective Equipment is the bottom of the hierarchy. It is the last line of defence, used when higher-order controls cannot adequately reduce the risk. PPE does not eliminate or reduce the hazard — it reduces the severity of the consequence if the hazard causes harm.

This distinction matters. A hard hat does not stop objects from falling. A harness does not prevent a fall. A respirator does not remove dust from the air. PPE protects the individual worker from the residual hazard that remains after all other controls have been applied.

Common PPE in Australian construction SWMS, with the applicable standards:

Hard hat (AS/NZS 1801) — protects against falling objects and head impacts. Required on virtually every construction site in Australia.

Safety glasses (AS/NZS 1337) — protects eyes from flying particles, dust, and splash. Minimum requirement for all construction work.

Steel-cap boots (AS/NZS 2210.3) — protects feet from crush injuries and punctures. Non-negotiable on any construction site.

Hearing protection (AS/NZS 1270) — required when noise exceeds 85 dB(A) over an 8-hour time-weighted average or 140 dB(C) peak. Most power tools exceed this threshold.

Hi-vis clothing (AS/NZS 4602.1) — required where mobile plant operates or near traffic corridors under Category 15 HRCW.

Fall arrest harness (AS/NZS 1891.1) — required for work at heights when edge protection is not reasonably practicable. Must be inspected before each use, fitted correctly, and connected to a certified anchor point rated to the required dynamic load.

Respirator (AS/NZS 1716) — required for dust, fume, or vapour exposure. Must be fit-tested to the individual worker. A respirator that does not seal to the face provides close to zero protection regardless of its nominal rating.

Why PPE sits at the bottom of the hierarchy: it only protects the person wearing it (not bystanders), it relies on correct selection, fit, and use, it can be uncomfortable leading to non-compliance, it degrades over time, and it creates a false sense of security if used as the primary control. An inspector who sees PPE as the primary control in a SWMS will specifically ask what higher-order controls were considered and why they were rejected.

A compliant SWMS does not just list controls — it demonstrates that you have worked through the hierarchy systematically. Here is how to document it properly so that an inspector, a PC reviewer, or a court can see the logic at a glance.

For each hazard in your SWMS, list controls in hierarchy order. Start with any elimination or substitution measures (even if you note them as not reasonably practicable), then engineering controls, then administrative controls, then PPE. Tag each control with its hierarchy level in square brackets.

Example for "Work at heights — roof replacement at 6 metres":

[Elimination] Not reasonably practicable — work requires access to existing roof structure. [Substitution] Diamond wire cutting substituted for abrasive cutting where concrete elements need to be removed, reducing silica and dust exposure during the strip. [Engineering] Edge protection installed on all roof perimeters and openings per AS/NZS 4994.1 before any roof access. [Engineering] Scaffold with full guardrails and toe boards for access and work platform. [Administrative] Fall protection plan documented and communicated at each pre-start briefing. [Administrative] Only workers with Working at Heights training (RIIWHS204E) within the last 2 years permitted on the roof. [PPE] Full-body harness (AS/NZS 1891.1) with dual lanyard, connected to certified roof anchor points rated to 15 kN, for work beyond 2 metres from edge protection.

This layout shows the inspector three things: elimination was considered first, there are two engineering controls in place, and PPE is only used for the residual gap where edge protection does not reach. That is a well-constructed hierarchy, and the document makes the reasoning visible without requiring the reviewer to interpret the SWMS author's intentions.

A good digital SWMS builder enforces this structure automatically. It prompts the preparer for engineering and administrative controls before PPE, and if the preparer tries to submit a SWMS with only PPE controls for a high-consequence hazard, the system flags it and suggests higher-order alternatives from its hazard knowledge base. The hierarchy is not optional, and building it into the tool ensures it is not an afterthought.