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AS 1657 2018 Overview for Fixed Platforms, Walkways, Stairways and Ladders
This Tech Talk Tuesday session with Edward Titley provides a practical walkthrough of how AS 1657:2018 applies to industrial access systems and how it ties into Treadwell FRP solutions. The focus is on fixed platforms, walkways, stairways, ladders and guardrails in back-of-house and maintenance environments, not public boardwalks or building egress stairs, which are typically covered by other standards such as AS 1428 and the National Construction Code.
The webinar also reinforces that the content is general guidance rather than site-specific engineering advice and that final interpretation of AS 1657 rests with Standards Australia and the project engineer.
Overview of AS 1657 2018 from the Session
Scope and intent
AS 1657 2018 sets out minimum requirements for the design, construction and installation of:
- Fixed platforms and landings
- Walkways and sloping walkways
- Guardrails and handrails
- Stairways
- Rung-type and step-type ladders
The aim is to provide safe access for the inspection, operation, and maintenance of plant and structures, especially on industrial sites, treatment plants, and similar facilities.
Design loads and deflection
From the session:
- Platforms and landings are designed for the dead load of the structure plus a minimum superimposed live load of 2.5 kPa as a uniformly distributed load, unless the real use case requires higher loads, such as heavy gearboxes or process equipment being set down for maintenance.
- Stair treads are checked for both a line load across the tread and a local point load, with the controlling case used for design.
- Maximum vertical deflection is span divided by 100 or 40 mm, whichever is less. Although this meets the standard, Edward notes that Treadwell typically designs for a span-to-width ratio of 250 to achieve a more comfortable walking feel.
These load and deflection limits are consistent with the safety intent of AS 1657 and related guidance material, which emphasise adequate strength and stiffness under service conditions.
Platforms, walkways and the 15 mm drop ball
Key points highlighted:
- The maximum slope for a level platform or landing is 3 degrees in any direction.
- The minimum clear walking width is 600 mm, with at least 2,000 mm of headroom above.
- Standing space of at least 600 mm must be kept clear of door swings and cross traffic on platforms and landings.
- Walking surfaces must be slip-resistant, typically demonstrated via AS 4586 testing for pedestrian surfaces
A clause that often catches projects out is the dropped object requirement:
- Where persons can access or work beneath a platform or landing, a 15 mm-diameter ball must not pass through the floor surface.
In the webinar, this is shown using Treadwell mini mesh with 13 mm precise openings on landings, while stair treads use a larger square mesh, where the clause does not explicitly apply in the same way. The 15 mm test is specified in industry guidance based on AS 1657 and is intended to limit dropped-object hazards.
Toeboards are required wherever objects could fall from a platform or landing, and can be fixed either to the guardrail system or to the floor grating, depending on the design.
Means of access and preferred angles
The session walks through a functional angle matrix for choosing the proper access type:
- Level walkway: 0 to 3 degrees
- Sloping walkway or ramp: 3 to 20 degrees, with 0 to 10 degrees preferred
- Stairways: 20 to 45 degrees, with about 30 to 38 degrees preferred
- 45 to 60 degrees is identified as a non-preferred range
- Step type ladders: 60 to 70 degrees
- Rung type ladders: 70 to 90 degrees, with 70 to 75 degrees preferred
This aligns with industry guidance that refers back to AS 1657 for suitable ranges for walkways, stairs and ladders.
Stairways and riser geometry
For stairways, the key geometric rules highlighted are:
- A flight should have a minimum of 2 risers and a maximum of 18 risers, with landings between flights.
- The minimum tread depth is about 185 mm, with typical values in the 215-355 mm range.
- Riser height is between about 130 and 225 mm.
- The classic comfort rule applies: 2R + G between about 540 and 700 mm, where R is riser and G is going.
- The maximum variation between riser heights in a given flight is 5 mm, which often causes issues during retrofits or when concrete tolerance has not been carefully controlled.
Contrasting nosings are required so that the edge of each tread is clearly visible.
Ladders, cages and rung spacing
The webinar summarises ladder requirements as:
- Twin stile rung type ladders: stile spacing typically 375 to 525 mm.
- Rung spacing generally 250 to 300 mm, with the bottom rung between 90 per cent and 100 per cent of the normal rung spacing above. This means rung spacing usually needs to be set per ladder, rather than using a single generic spacing for all heights.
- Ladder cages or side screens are required when the fall distance exceeds 6 m, unless a compliant fall-arrest system is used.
Step-type ladders combine characteristics of stairs and ladders, with deeper treads and riser constraints similar to stairways, but steeper overall angles.
Guardrails and testing of proprietary systems
For guardrails and handrails, the session calls out:
- Minimum height of the top rail is 900 mm above the walking surface or stair nosing.
- One or more intermediate rails must be provided to ensure that the maximum clear gap between rails or between a rail and the toeboard is 450 mm. If no toeboard is present, the lowest rail must be no more than about 560 mm above the floor.
- Guardrails must resist specified horizontal and vertical design loads, such as a concentrated point load and a distributed line load, with a maximum elastic deflection of 100 mm under test.
AS 1657 includes tables of steel and aluminium sections that can be deemed to comply without further testing if fabricated correctly. Any proprietary system outside those tables, such as FRP handrail systems, must be physically tested in accordance with the standard’s prescribed test method and reported format, usually in an accredited laboratory.
In the webinar, Edward notes that Treadwell’s FRP RailEX® system has been tested to these requirements and that designers should always request and review test reports for any proprietary handrail product.
Key Benefits
Clear design rules for safer access
AS 1657 2018 provides designers with clear rules for loads, geometry, slip resistance, and drop-ball performance, reducing ambiguity and helping ensure that fixed platforms, walkways, stairs, and ladders are safe for maintenance and inspection tasks.
Better alignment between design intent and real use
The session emphasises using the standard as a baseline, then checking real operating conditions such as heavy gearbox removal, frequent equipment handling or aggressive environments so that load levels, mesh selection and toeboard details actually match how the asset will be used.
Reduced dropped object and fall risks
Requirements such as the 15 mm drop ball on platforms and landings above occupied areas, minimum guardrail heights, and toeboards directly address common risks such as dropped tools and falls from height, helping protect both users on the platform and people working below.
Improved user comfort and accessibility
Controlling stair riser consistency, tread going, headroom and walkway slopes provides safer, more comfortable access for regular users, which reduces slips, trips and fatigue for operations and maintenance crews.
Confidence through tested systems
The requirement for proprietary guardrail and handrail systems to be tested encourages the use of documented, verified systems. When combined with Treadwell’s own test data and online tools, this gives specifiers greater confidence that designs will meet AS 1657 performance criteria in practice.
Applications
The principles covered in this video apply wherever industrial access is needed for inspection, operation or maintenance, for example:
- Water and wastewater treatment plants
- Access platforms around tanks, screens, clarifiers and chemical dosing skids
- Sloping walkways, ladders and stairways on elevated pipe bridges and galleries
- Mining, mineral processing and heavy industry
- Fixed platforms around conveyors, crushers, mills and agitators
- FRP mini mesh landings above lower plant levels, where the 15 mm drop ball requirement is critical
- Power generation and substations
- Walkways and stairs around switchgear, transformers and cooling equipment
- Guardrails and ladders that must interface with other electrical safety requirements
- Industrial buildings and factories
- Rooftop walkways for plant access, with slip-resistant surfaces and compliant guardrails
- Internal service platforms and maintenance ladders for HVAC and process equipment
- Food, chemical and coastal facilities
- Corrosion-resistant FRP platforms, handrails and ladders where steel or aluminium would require intensive coatings maintenance to meet AS 1657 performance over time.
Key Moments
- 00:20 👋 Welcome message and introduction for the Tech Talk Tuesday session hosted by Edward Titley at Treadwell.
- 02:48 ⚠️ Disclaimer that the discussion will be general commentary and not site-specific advice or recommendations.
- 03:14 📏 Stairways should support a dead load plus a superimposed live loading of at least 2.5 kPa.
- 05:00 🏗️ It's crucial to ensure that 15 mm drop balls cannot pass through openings where individuals can work beneath a platform or landing.
- 07:00 🚧 For walkways, the maximum slope in any direction is 3°, whereas sloping walkways should not exceed 20° in the direction of travel.
- 09:44 📐 Stairways must have a minimum tread depth of 185 mm and must ensure the rise does not exceed 18 mm.
- 12:11 📏 Ladder design specifications include a width between styles of 375 to 525 mm and must conform to specific rung spacing requirements.
- 15:20 ⚖️ Handrails and guardrails must meet loading requirements, including 600 newtons outwards or downwards on any rail or post.
- 16:28 🧪 Non-standard handrail systems must be mechanically tested in an approved lab rather than relying on engineer sign-off alone.
- 24:07 📅 Reminder of the next Tech Talk Tuesday session and appreciation for participant engagement and support.
Why Treadwell?
Compliant by design
Treadwell designs its FRP platforms, walkways, stairs, ladders, and guardrails specifically to AS 1657 requirements, including loads, deflection limits, geometry, slip resistance, and drop-ball performance, ensuring compliance is baked into the system from the outset.
Proven FRP handrail performance
The RailEX® FRP handrail system has been tested in accordance with AS 1657 guardrail test methods, providing documented performance under the prescribed point and line loads and deflection limits so that specifiers can select FRP with confidence.
Mesh options tailored to the 15 mm rule
Products such as FRP mini mesh with 13 mm precise openings are ideal for platforms and landings where the 15 mm drop ball requirement applies, while standard square mesh and stair treads can be used where larger openings are acceptable.
Design tools and engineering support
Treadwell backs its products with tools such as the TreadSpec™ online calculator, plus internal structural and applications engineers who can assist with checks of loads, spans, and deflections, including more complex cases such as point loads on grating or multi-span layouts.
Site-specific advice and lifecycle focus
The team regularly conducts site visits and project-specific guidance to align AS 1657 requirements with plant layout, maintenance practices, and environmental conditions, aiming for safe, durable, low-maintenance FRP access systems throughout the asset’s whole life.
