AS 1657 — Fixed Platforms, Walkways, Stairways and Ladders
Australian Standard for design, construction and installation of industrial access equipment
What is AS 1657?
AS 1657 is the Australian Standard that governs the design, construction and installation of fixed platforms, walkways, stairways and ladders used for industrial and commercial access purposes. It specifies minimum requirements for structural strength, dimensional limits, handrail heights, tread depths, riser heights, ladder rung spacing and slip resistance — essentially everything that determines whether an access structure is safe and legally compliant in Australia.
The standard applies to permanent fixed access structures including maintenance platforms, mezzanine walkways, roof access ladders, machinery access stairs, conveyor access platforms, and any fixed ladder or stairway installed in a workplace. Compliance with AS 1657 is required under the Work Health and Safety (WHS) Act across all Australian states and territories, making it a mandatory reference for engineers, fabricators and building certifiers.
Current edition: AS 1657-2018 (superseded AS 1657-1992). The 2018 edition introduced significant changes to handrail requirements, ladder cage rules, and added new requirements for roof access hatches.
AS 1657 Stairways — Key Design Requirements
AS 1657 stairs must comply with the following dimensional requirements to be considered compliant access stairways:
| Parameter | AS 1657-2018 Requirement |
|---|---|
| Pitch (slope angle) | 20° to 45° (preferred range 30°–38°) |
| Tread depth (going) | Minimum 215mm (at 45°) to 355mm (at 20°) |
| Riser height | Maximum 225mm; minimum 125mm |
| Stair width (clear) | Minimum 550mm (single person); 900mm recommended |
| Handrail height | 900mm–1100mm above nosing line |
| Handrail graspability | Circular rail 30–50mm diameter; or graspable profile |
| Mid-rail | Required at 450mm–600mm above nosing |
| Toe board / kick plate | Minimum 100mm high on open sides |
| Headroom clearance | Minimum 2000mm at all points |
The 2R + G formula (twice the riser plus the going equals 580–620mm) is used to check stair ergonomics — for example, a 175mm riser and 270mm going gives 2×175 + 270 = 620mm, which is acceptable under AS 1657.
AS 1657 Stair Handrail Requirements
Handrails on AS 1657 stairways must be continuous on both sides for stair widths exceeding 1000mm, or on at least one side for narrower stairs. The handrail must be graspable along its full length and return to the wall or post at both ends to prevent clothing catching. Intermediate posts must be spaced at maximum 1800mm centres. All handrail connections must be capable of withstanding a 630N point load applied in any direction.
AS 1657 Ladders — Design Requirements
Fixed ladders under AS 1657 are divided into three categories based on height and location. The standard specifies strict requirements for rung spacing, side rail width, clearance behind rungs and the use of safety cages or fall arrest systems.
| Parameter | AS 1657-2018 Requirement |
|---|---|
| Rung spacing (pitch) | 225mm–300mm (uniform) |
| Clear width between side rails | Minimum 400mm |
| Clearance behind rung (foot space) | Minimum 175mm |
| Clearance in front of rung (body space) | Minimum 650mm (uncaged) / 700mm with cage |
| Side rail extension above landing | Minimum 1000mm above highest rung or landing |
| Safety cage requirement | Required for ladders >3000mm climb height (or fall arrest system) |
| Cage diameter | 650mm–800mm internal |
| Cage hoops | Maximum 900mm spacing |
| First cage hoop from base | 2000mm–3000mm from standing level |
| Rest platform (rest landing) | Required every 6000mm of climb |
AS 1657 Ladder Cage vs Fall Arrest
The AS 1657-2018 update changed the approach to fall protection on fixed ladders. A safety cage (also called a ladder cage or hoop guard) is the traditional requirement for ladders over 3m climb height. However, AS 1657-2018 now also permits a compliant vertical fall arrest system (a fixed rail or cable fall arrest system to AS/NZS 1891.2) as an alternative to a cage — and in many cases this is preferred because it allows unobstructed access for tools and equipment.
AS 1657 Handrails and Guardrails
AS 1657 handrail requirements apply to platforms, walkways and stairways. The standard differentiates between a handrail (a graspable rail for support while moving) and a guardrail (a barrier to prevent falls at open edges).
| Parameter | AS 1657-2018 Requirement |
|---|---|
| Guardrail height (platform edge) | 900mm minimum; 1100mm recommended for high-risk areas |
| Mid-rail height | 450mm–600mm |
| Toe board height | Minimum 100mm |
| Maximum open gap (mid-rail) | 500mm |
| Post spacing | Maximum 1800mm |
| Load capacity | 630N point load in any direction at top rail |
| Distributed load | 730N/m along top rail |
AS 1657 Platforms and Walkways
Fixed platforms and walkways under AS 1657 must meet requirements for floor loading, surface slip resistance, edge protection and clearances. Key requirements include:
- Minimum platform width: 600mm clear (750mm preferred for regular use)
- Floor loading: Minimum 2.5 kPa for general access; 4.0 kPa for maintenance platforms; structural engineer to verify for specific loads
- Slip resistance: Open grating (minimum 25×3 bar grating with 30mm max opening) or chequerplate to AS/NZS 4671; must achieve P4 slip rating or better when wet
- Overhead clearance: Minimum 2100mm at all points along the walkway
- Edge protection: All open edges require guardrails and toe boards as above
- Maximum gap in floor: 30mm in any direction (to prevent heel entrapment)
AS 1657-1992 vs AS 1657-2018 — Key Changes
The 2018 revision significantly updated several areas compared to the 1992 edition:
- Ladder fall protection: AS 1657-2018 allows fall arrest systems as an alternative to cages — the 1992 edition required cages on all ladders over 3m
- Handrail graspability: 2018 introduces more specific requirements for graspable profiles and adds testing requirements
- Roof access hatches: New requirements for hatches serving fixed ladders, including minimum opening sizes and hatches that stay open when accessed
- Stair pitch: Maximum pitch increased from 45° to allow steeper ships-ladder style stairways in constrained spaces (with additional requirements)
- Structural loads: Updated to align with AS/NZS 1170.1 structural loading standard
Many structures in Australia still carry AS 1657-1992 documentation. When undertaking modifications, the current 2018 edition applies to any new work, while existing compliant structures may remain under the 1992 standard if no modifications are made.
AS 1657 Shop Drawings — What Engineers and Fabricators Need
For fabrication of AS 1657-compliant stairs, ladders and platforms, shop drawings must include:
- Plan, elevation and section views with all critical dimensions (rise, going, width, handrail heights)
- Material callouts per Australian Standards (typically AS/NZS 3678 Grade 350 structural steel, or AS/NZS 1734 aluminium)
- Weld symbols and inspection category per AS/NZS 1554.1 (typically GP category for access structures)
- Surface treatment specification (hot-dip galvanise to AS/NZS 4680, or paint system)
- Connection details to supporting structure with bolt grades and edge distances
- AS 1657 compliance note referencing the applicable edition
- Structural engineer’s certification for platforms over 3.0 kPa loading
ASTCAD produces AS 1657-compliant shop drawings for stairs, ladders, platforms and walkways for fabricators and construction firms across Australia. Our structural drafters are experienced in AS 1657-2018 requirements and work to AS 1100 drawing standards. Request a free quote.
Frequently Asked Questions — AS 1657
What is the minimum handrail height under AS 1657?
The minimum handrail height on platforms and walkways under AS 1657-2018 is 900mm measured from the walking surface to the top of the rail. For high-risk locations (adjacent to machinery, open edges above 3m, or where falls would result in severe injury), 1100mm is recommended. On stairways the height is measured vertically from the nosing line of the stair treads.
What height does an AS 1657 ladder require a cage?
Under AS 1657-2018 a cage (or alternative fall arrest system) is required for fixed ladders where the climb height exceeds 3000mm (3 metres). The cage must begin no more than 3000mm from the base of the ladder and must extend to the top landing. Rest platforms are required every 6000mm of climb. Note that under the 2018 edition a compliant fall arrest rail system can substitute for a cage.
What is the maximum riser height for AS 1657 stairs?
The maximum riser height under AS 1657-2018 is 225mm. The minimum riser height is 125mm. Riser heights must be uniform throughout a flight — a variation of more than 5mm between any two adjacent risers is not permitted under the standard.
Does AS 1657 apply to residential stairs?
AS 1657 applies to industrial and commercial access structures — maintenance platforms, machinery access, mezzanine walkways, and industrial stairways. Residential stairs in houses and apartments are covered by the National Construction Code (NCC) / Building Code of Australia (BCA) Part 3.9, which references AS 1428 for accessibility requirements. If you have a stairway in an industrial or commercial setting, AS 1657 applies.
Where can I download AS 1657-2018?
The current AS 1657-2018 standard is available for purchase from Standards Australia. An older reference copy of AS 1657-1992 is available via the link below. For most fabrication and drafting purposes, ensure your engineer has access to the current 2018 edition as it contains significant changes from 1992.
Download AS 1657-1992 reference PDF →
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