Why access steelwork belongs in the machinery order

Most industrial machines have at least one place a technician has to reach: a valve bank, a filter housing, a gearbox inspection cover, a lubrication point, a level transmitter. Reaching it safely needs a walkway, a platform, a stair or a fixed ladder, and a guard-rail system that keeps people from falling off the edge. In practice this steelwork is welded fabrication, and it is frequently quoted together with the machine frame, the chute or the base skid rather than as a separate package.

The risk for a buyer is that access steelwork looks simple on a drawing and becomes expensive after delivery. A handrail height that does not match the site standard, a missing toe plate, a platform width that is too narrow for the tools the job needs, or a grating that becomes a slip hazard when it is wet are all design and specification problems that arrive as disputes at the workshop gate.

This guide covers what to put in the enquiry when platforms, walkways, stairs and handrails are fabricated to the buyer's drawings. It stays on the purchase decision. Realjet manufactures welded and machined machinery components to customer drawings, and access steelwork is reviewed inside that scope through the contract manufacturing service rather than sold as a catalogue product.

What the drawing package has to contain

The approved access drawing is the contract. Where it is ambiguous, the fabricator has to guess, and the guess is not covered by the price. A workable package includes:

  • general arrangement showing the machine outline, the platform extents and the access route between levels;
  • fabrication drawings for the supporting structure, with member sizes, connection details and weld symbols;
  • the flooring schedule: grating or plate type, mesh or bearing bar size, panel sizes and fixing method;
  • handrail, knee rail and toe plate details, including post spacing and how the posts are anchored or bolted;
  • stair geometry, or ladder details where a stair is not used;
  • the hole schedule for bolted connections, with hole diameter, position tolerance and the datum they are measured from;
  • the finish specification for each part, and the site environment it has to survive;
  • the applicable welding standard and the weld quality level, plus the inspection and documentation expected at handover;
  • the standard or national regulation the access has to satisfy, named by edition.

Two items in that list are usually missing. The first is the design load; a walkway schedule is expected to state the load it was designed for. The second is the responsibility split. Unless the buyer also buys the design, the load case, the geometry and the conformity of the access arrangement with the machinery safety requirements stay with the machinery designer. The fabricator's job is to build the approved geometry, hold the stated tolerances and report anything that cannot be met.

Loads and dimensions that come from the access standard

Access to machinery is one of the few areas where a buyer can hand the fabricator a standard instead of an argument. The ISO 14122 series covers permanent means of access to machinery. ISO 14122-2:2016 covers working platforms and walkways, Part 3 covers stairs, stepladders and guard-rails, and Part 4 covers fixed ladders. Parts 2 and 3 carry most of the numbers that end up on a fabrication drawing.

For platforms and walkways, ISO 14122-2 sets minimum loads of 2 kN per square metre uniformly distributed for the structure, and a 1.5 kN concentrated load applied at the most unfavourable position over an area of 200 mm by 200 mm for the flooring. Deflection of the flooring is limited to one two-hundredth of the span, and the difference in height between a loaded floor panel and an adjacent unloaded one is limited to 4 mm. Flooring openings are also regulated so that a 35 mm ball cannot pass through, tightened to 20 mm above places where people work rather than merely pass. Clear width for a normal single-user walkway starts at 800 mm, and clear passage height at 2100 mm.

Those figures are minimums, not targets. A platform that has to hold a pump on a temporary basis, carry a toolbox and take two people during a shutdown needs a higher load case, and the buyer is the party who knows that.

Guard-rails, toe plates and the fall prevention detail

ISO 14122-3 requires a guard-rail once the possible fall height exceeds 500 mm, or when the gap between the platform and the machine or wall is more than 180 mm. The guard-rail is at least 1100 mm high, with an intermediate knee rail or equivalent protection; clear spaces between handrail, knee rail and toe plate are limited to 500 mm, and where vertical uprights replace the knee rail, the clear distance between them is limited to 180 mm. A toe plate with a minimum 100 mm upstand sits no more than 12 mm above the walking level, and gaps between adjacent toe plates are limited to 20 mm. Post centres are preferred at a maximum of 1500 mm; beyond that the anchoring and the fixings need specific attention.

North American projects work to a different set of numbers. OSHA 29 CFR 1910.29 puts the top rail at 42 inches plus or minus 3 inches above the walking surface, requires a midrail about halfway unless a wall or parapet at least 21 inches high already exists, limits intermediate vertical members to 19 inches apart, and sets a toe board at a minimum of 3.5 inches with no more than a quarter inch of clearance. The top rail has to resist 200 pounds, the midrail 150 pounds and the toe board 50 pounds. Fall protection becomes mandatory at 4 feet under 29 CFR 1910.28.

For European projects there is a regulatory reason to settle this early. Regulation (EU) 2023/1230 replaces the Machinery Directive 2006/42/EC, and applies from 20 January 2027 with no transitional overlap. Access and protection against slips, trips and falls remain essential health and safety requirements, so a platform designed only against the old directive may need review before the machine is placed on the market.

Flooring, drainage and slip resistance

Three flooring decisions drive most of the complaints. Grating drains and carries a high load for its weight, but the mesh has to be tight enough to satisfy the falling object requirement. Chequer plate is cheaper and easier to fabricate, but it collects water and becomes slippery, so it needs a defined pattern, surface profile and, on external platforms, a fall in the correct direction. Ribbed walkways used on ramps with a pitch between 10 and 20 degrees are expected to use ribs of 10 mm to 20 mm in width and height with a spacing of 400 mm to 500 mm.

The material choice follows the site. A plant next to the coast or inside a fertiliser works will not get a long life from untreated carbon steel, and the drawing should say which parts are hot dip galvanized to ISO 1461, which are painted, and which are stainless. Mixed metals need isolating washers or a compatible fixing to avoid galvanic corrosion, and drainage paths should be positioned so water cannot sit in a joint or a folded section.

Fabrication scope: welding, machining and tolerances

Access steelwork is a welding job with a machining edge. The welding standard has to be named, whether that is AWS D1.1 for structural steelwork, ISO 3834 for quality requirements and ISO 5817 for weld quality levels, and the drawing should state the level of inspection and whether repair is allowed. Bolted connections at the machine frame are a machining decision: hole position, hole diameter, base plate flatness and the datum from which they are measured need a tolerance class, typically through ISO 2768 for general tolerances or a geometric tolerance scheme such as ASME Y14.5 or ISO 1101 for the interfaces that matter.

The scope of the welding procedure and NDT requirements belongs in the RFQ, not in the delivery discussion. So does the surface treatment specification, because galvanizing after fabrication changes hole clearances and thread condition unless the drawing accounts for it.

What to inspect before shipment

Access steelwork is inspected as a structure, not as a picture. The useful checks are dimensional: overall platform length and width, stanchion spacing against the drawing, handrail height above the walking level, toe plate upstand and clearance, hole positions at the bolted interfaces, and a trial fit of any sub-assembly that has to line up on site. Welding inspection records should match the level named in the drawing, coating thickness should be reported for galvanized parts, and every part should be marked so the site team can match it to the assembly drawing.

The first article inspection approach is worth applying when a project has repeating platform bays. One bay is inspected against the drawing and approved, then the rest are checked against the approved first item rather than re-measured in full. Packing and marking also need a written rule, especially when the platform sections ship in a container with the machine frame, and the packaging and export scope should say who supplies lifting points, how the parts are protected on the exposed edges and which documents travel with the shipment.

Compare quotations on scope, not on weight alone

Access steelwork is often compared on price per kilogram, which hides the differences that decide the outcome. Ask each bidder to state the welding standard and inspection level applied, the tolerance basis for the bolted interfaces, the finish schedule with coating thickness, the inspection records included, the packing method, and whether they priced the design review of the access drawing or only the fabrication of it. Where a bidder has assumed a lighter grating, a thinner toe plate or a simpler handrail fixing than the drawing shows, the assumption should appear as a deviation.

A short set of answers to those questions makes the quotations comparable, and it protects the buyer from discovering the gap after the steel has been cut.

Realjet reviews access enquiries from the approved drawings, the standard or regulation to be applied and the required inspection evidence. Send the drawing package, the loading basis and the finish schedule through the contract manufacturing enquiry route so the reply can address the actual scope.