“Do I need a platform, stairway or ladder here — and can I simply make the dimensions fit AS 1657?”
Most access problems are created before dimensions are checked. The key decision is what people need to do, how often they do it, what they carry and what hazards the access route introduces.
The practical answer
A stairway may be more appropriate than a ladder for frequent access, tool carrying or emergency use. A platform may be required to perform the task safely rather than forcing a worker to reach from a ladder.
The Standard interacts with structural design, slip resistance, machinery safety, building requirements and fall-risk controls.
For machine access, the safest outcome may be to redesign the equipment or bring routine tasks to ground level rather than add more access steelwork.
Where this Standard fits
- Maintenance platforms around tanks, vessels and machinery
- Fixed walkways and crossover access
- Industrial stairways and landings
- Step-type ladders and fixed ladders
- Guardrails and toeboards associated with fixed access
- Permanently configured but movable workplace platforms
- A universal substitute for the National Construction Code
- A justification for using a ladder where safer access is reasonably practicable
- A machinery guarding Standard
- A fall-arrest system Standard
- A complete structural design code for the supporting steelwork
- Permission to ignore the task, frequency of use or materials carried by the user
Choose the access system before checking dimensions
Start with the work task, not with the available gap in the model.
A good result needs the equipment definition, loads, design method, fabrication, inspection and operating limits to describe the same real system.
Key engineering concepts to understand
Access selection is a risk decision
A geometrically compliant ladder can still be a poor choice if workers use it frequently, carry parts or need both hands for the task.
The access route is part of the work system
Consider how the user approaches, opens gates, transitions between levels, carries tools and reaches the actual work position.
Falls are not the only hazard
Head strikes, slips, dropped objects, entrapment, hot surfaces and exposure to moving machinery can be introduced by the access design.
Supporting steelwork needs its own design basis
AS 1657 identifies structural Standards for materials and load design. The access geometry and structural capacity are related but not interchangeable checks.
Machine access should not create a danger-zone shortcut
Platforms and stairs must be coordinated with guarding and safe isolation so that access does not inadvertently put users inside hazardous zones.
Existing access deserves task-based review
An old ladder may have been adequate for occasional inspection but become unsuitable after the task, frequency or equipment arrangement changes.
Detailed engineering case studies
The examples below show how the Standard changes a real engineering decision. They are not clause summaries or universal answers; each case starts with the equipment, task and evidence available.
Compliance review of vertical ladders on chemical storage tanks
A chemical storage facility has numerous existing vertical ladder systems providing access to tank roofs, instruments and maintenance points. The ladders were installed at different times and to different details, so the task is to identify where each system departs from the current access basis and what should be prioritised for upgrade.
This is a classic AS 1657 application, but a useful review is more than measuring rung spacing. The assessment has to follow the complete user journey from ground level to the work position and back again.
What made the job difficult
- Ladder geometry and clearances vary between tanks.
- Some climbs terminate through roof openings or close to guardrails, pipework and tank appurtenances.
- Cages, fall-arrest systems and intermediate landings are inconsistent across the site.
- Corrosion, chemical exposure and previous modifications can affect the supporting structure and attachment details.
How the engineering review should proceed
- Survey each ladder as a system: lower approach, access restriction, rungs and stiles, rear and side clearances, fall distance, cage or fall-arrest provision, landings, top transition, handholds and the destination work area.
- Record whether a fall could continue past a lower landing rather than considering vertical ladder height in isolation.
- Check whether the final step-off forces the user to turn, reach over a guardrail, step around pipework or enter an exposed roof area without a secure transition.
- Separate dimensional non-conformances from condition defects such as corrosion, loose fixings, damaged cages and inadequate parent-structure capacity.
A practical deliverable is a ladder-by-ladder register with photographs, measured findings, risk ranking and upgrade recommendations. The highest-priority actions are often poor transitions, uncontrolled fall exposure, damaged attachments or unsafe access routes rather than one isolated dimensional deviation.
Vertical ladder access into water pipe pits
A water utility needs a repeatable method to review fixed vertical ladders into valve and pipe pits. Pit depths, hatch arrangements, ladder positions and internal pipework vary, and some pits are confined spaces.
AS 1657 can govern the fixed access geometry, but the safe-access decision cannot be separated from the hatch, the top transition, fall exposure, confined-space entry and the ability to rescue a person from below ground.
What made the job difficult
- The ladder may start directly below a small hatch with limited handhold continuity.
- Pipework can reduce the climbing envelope or block a safe step-off at the bottom.
- A cage may be impractical within the pit geometry, making fall-arrest considerations relevant for deeper access.
- The ladder can become part of the emergency retrieval path even though it was designed only for routine access.
How the engineering review should proceed
- Assess the surface approach and hatch first: opening size, guarding while open, slip/trip hazards and whether the user can establish secure hand contact before stepping onto the ladder.
- Measure the climbing space and identify intrusions from valves, pipework, brackets and wall projections.
- Review the bottom landing and task area so the worker does not step directly into water, pipework or another hazard.
- Coordinate the access review with confined-space isolation, standby, rescue and retrieval requirements rather than treating the ladder as a standalone item.
The recommended solution may include ladder modification, improved handhold extension, hatch guarding, relocation of obstructions, a different fall-protection strategy and changes to the confined-space rescue plan. A ladder can be dimensionally close to AS 1657 and still form part of an unsafe entry system.
Access platform for a mobile hydraulic liner-handler crane
A mobile hydraulic crane used as a liner handler requires a dedicated operator and maintenance platform. The platform moves with the machine and must provide access around hydraulic equipment and the working area without exposing users to falls or machine hazards.
AS 1657 explicitly addresses fixed and permanently configured but movable workplace platforms. That makes it highly relevant to the access geometry, but the final design also has to integrate machinery and crane hazards.
What made the job difficult
- The platform is mobile with the machine rather than fixed to a building.
- Hydraulic cylinders, hoses and moving crane components create crush and entanglement zones.
- The machine can sit on uneven ground, so platform orientation and access geometry may change in service.
- Operators need safe access for routine work, inspection and emergency egress.
How the engineering review should proceed
- Define every task performed from the platform, including operation, inspection, hose access, cleaning and maintenance.
- Apply AS 1657 to platform width, surfaces, guardrailing, access between levels and structural loading, but check whether the machine configuration creates additional movement or reach hazards.
- Ensure the access route does not place a person within the crane or hydraulic danger zone during normal or foreseeable tasks.
- Check safe egress in relevant machine positions and operating configurations, not only in the workshop park position.
The resulting platform should be documented as part of the machine design, not treated as a bolt-on walkway. The best design coordinates AS 1657 access geometry with the machine risk assessment, hydraulic isolation, crane operating envelope and structural design of the supporting frame.
Common mistakes
Access is squeezed into whatever gap remains after equipment layout, creating awkward transitions and poor task positions.
PPE, carried items, evacuation and actual movement can justify more generous geometry.
Frequency and task demands are overlooked because a ladder is cheaper and easier to fit.
The route may comply but leave the worker standing too low, reaching too far or exposed to the hazard being serviced.
A new platform can place people closer to nip points, drives or unexpected movement unless guarding and isolation are reviewed.
Posts, baseplates, grating supports and the parent structure still need a defensible structural design basis.
Information to gather before making the decision
Task performed at the destination
Frequency and duration of access
Number and capability of users
PPE, tools, components and materials carried
Available space and possible equipment relocation
Height changes and transition points
Slip, weather, contamination and corrosion exposure
Nearby machinery, hot surfaces and process hazards
Emergency access or egress requirements
Structural support and fixing details
Existing access and incident history
Applicable NCC, WHS and site-specific requirements
What should happen next?
Related AS Applied content
Source basis & limitations
- This page intentionally explains selection logic and interfaces rather than reproducing dimensional tables or figures.
- Building regulation, workplace legislation and site requirements can affect the final access solution and should be checked separately.
Need the Standard applied to real equipment?
AS Applied helps frame the question. Detailed assessment, design, FEA, repair design, verification and RPEQ services are provided through XPO Engineers.