AS 1657 covers the design, construction and installation of fixed platforms, walkways, stairways and ladders. It is referenced by the National Construction Code, by most mine-site engineering standards and by safety regulators after an incident, which makes it the yardstick an inspector reaches for first. Below are the non-compliances that come up again and again on the sites we work on, roughly in order of how often we find them. The figures quoted are the commonly applied requirements from the current edition; always confirm against the standard and any stricter site rule.
1. Guardrails that are too low, or have gaps
Expected: a top rail between 900 and 1100 mm above the walking surface, an intermediate rail so that no opening exceeds 450 mm, and a toeboard at least 100 mm high wherever something could fall onto people or plant below.
Found: older plant with rails at 850 mm, toeboards missing entirely, rails that stop short at the top of a stair, and gaps at corners and posts where sections were fitted by eye. Cheap to fix, and the first thing any auditor measures.
2. Stairs at the wrong pitch, or with uneven steps
Expected: stairways between 20 and 45 degrees, step-type ladders between 60 and 70 degrees, rung ladders between 70 and 90 degrees. Within a flight, every riser and every going the same. Landings where flights get long, with headroom kept clear.
Found: "stairs" built at 55 degrees that are neither a stair nor a ladder, and treads that vary by 20 mm because the stringer was cut on site. Uneven risers are a trip hazard the body never learns; they are one of the most common causes of falls on stairs. Pitch and rise are structural, so this one is not a cheap retrofit.
3. Ladders without the extras the height demands
Expected: a rung ladder that climbs more than six metres needs a cage or a fall-arrest system, with landings at intervals; stiles or a handhold extending above the landing so there is something to hold while stepping off; and where a ladder arrives through a floor opening, a self-closing gate rather than a chain.
Found: tall ladders with no cage and no landing, chains across ladder openings that are left unhooked, and ladders that stop flush with the platform. Gates and handholds are quick wins; cages and landings are a small project.
4. Walkways narrowed by everything else
Expected: at least 600 mm of clear width and 2000 mm of headroom along the whole route.
Found: pipe runs, cable trays, valve handwheels and conduit added over the years until the walkway is 400 mm wide at the pinch point, and a beam at head height with a strip of yellow tape on it. This is usually a coordination problem rather than a fabrication one: nobody owned the corridor. Why that happens on brownfield jobs.
5. Grating that is not fixed, or not rated
Expected: grating and flooring designed for the specified live load and any concentrated loads, fixed down with clips at every panel, with no unsupported edges and no level changes at panel joins.
Found: panels that rock, panels lifted for maintenance and never clipped back, and a 15 mm step where a heavier panel was substituted. Loose grating is an incident waiting for a shift change.
6. Platforms that do not reach what they are for
Expected: a platform positioned so that the valve, filter or motor it serves can be operated and removed from it without leaning over the guardrail or standing on the rail.
Found: platforms built to the drawing while the equipment was rotated or moved, so the operator now climbs the rail with a spanner. The fix is either extending the platform or moving the equipment, and it is far cheaper to catch at design review than after commissioning.
7. No engineering behind the structure
Expected: the platform and its supports designed to the loads in AS/NZS 1170 and AS 4100 or AS 3990, with the load path traced to the ground, and RPEQ certification where the work is in Queensland.
Found: platforms fabricated from a sketch, brackets welded to pressure vessels and pipework without the owner's knowledge, and access steel hung off structure that was never checked for the extra load. These are the ones that fail suddenly rather than gradually.
8. No records
Expected: drawings that match what was built, material certificates, and a record of any modifications.
Found: nothing. Without records, every future change starts with a site survey. Getting as-builts done once and properly.
Checking what you already have
A half-day walk with a tape measure and a camera finds most of the above. Measure rail heights and openings, check every stair for pitch and uniform risers, look for gates and cages on ladders, check clear width along each walkway, and rock every grating panel. Photograph anything doubtful with the tape in the shot. Then sort the list into three piles: fix now (rails, toeboards, gates, clips), fix at the next shutdown (landings, cages, platform extensions), and call the engineer (pitch, structure, anything welded to equipment).
Guardrails, toeboards, gates and clips are almost always worth fixing in place. A stair at the wrong pitch, or a platform whose structure was never designed, is usually cheaper to replace than to justify.