Industrial walkway width requirements have a straightforward starting point: for permanent access to machinery, the recommended minimum clear width is 600 mm, with 800 mm preferred where the route is used regularly. Headroom over that route is 2 100 mm.
The complication is that the machinery standard is not the only rulebook a walkway can sit under, and a route that satisfies it can still be non-compliant under the regime that actually applies. Establishing which one governs is the first step, not the last.
The figures from the machinery access standard
EN ISO 14122 covers permanent means of access to machinery, and its part on working platforms and walkways is where the dimensions live. Alongside the width and headroom figures, it sets out the fall protection that goes with them, and those requirements are what most often get missed in a specification.
| Item | Requirement |
|---|---|
| Clear width, minimum | 600 mm |
| Clear width, preferred | 800 mm |
| Headroom | 2 100 mm |
| Guard-rail height | 1 100 mm minimum |
| Maximum vertical gap | 500 mm |
| Toe-plate upstand | 100 mm minimum |
Guard-rails are required where there is a risk of falling from 500 mm or more, and the 500 mm gap limit is what forces a knee rail between the top rail and the toe-plate. The toe-plate itself has to sit within 10 mm of the walking surface, since a gap under it defeats the purpose.
Clear width means clear
The figure is measured between obstructions, not between the structural edges of the deck. Handrail standards that stand inboard of the deck edge take width. So do cable trays, small-bore pipework, isolation valves, lighting and any equipment mounted at waist height along the route.
This is the most common way a compliant drawing becomes a non-compliant installation. The walkway is built at 800 mm, a cable tray is added along one side during commissioning, and the route is now 650 mm at that point. Specifying the clear width as a maintained dimension, with a note that services must not encroach, is a one-line fix that survives the whole life of the installation.
When 600 mm is not enough
The minimum is a minimum for one person passing in one direction while walking normally. Four situations push the requirement up and none of them is unusual.
Two-way traffic needs room for people to pass, and on a busy route that means considerably more than the preferred figure. Carrying tools or components changes the effective width a person occupies, and a route used for moving equipment should be sized for the largest item rather than for the operator. Where a casualty might have to be carried out on a stretcher, the route has to accommodate that, and the required width is set by the stretcher and its handlers rather than by the standard. Finally, where the walkway forms part of an escape route, the width follows from the number of people who have to use it, which is a capacity calculation rather than a dimension from a table.
Which rulebook applies
Access to machinery sits under the machinery access standard. A walkway that forms part of a building is governed by national building regulations and workplace health and safety rules, which set their own widths and escape provisions. Process plant clients frequently impose a company standard that is stricter than either. A route can easily be subject to two of these at once, and where they differ the stricter figure governs.
The practical consequence is that the applicable regime belongs in the enquiry rather than being inferred by the supplier, and establishing which set of rules applies before fabrication also determines what documentation has to accompany the delivered structure.
Width has a structural consequence
Every extra hundred millimetres of width is extra deck area, extra imposed load and extra self-weight, all of which feed into the section depth and the spacing of supports. On a long elevated run this is not a rounding error, and a client who widens a route late in design frequently finds the support grid changing with it.
The reverse also holds. Where supports are already in place and cannot be moved, the available span limits what the deck can be, and that is the point at which material choice starts to matter, since a stiffer deck spans further for the same depth.
What to state in the specification
Give the clear width and say it must be maintained clear of services. Name the standard or regulation the route is designed under. State whether the route is two-way, whether equipment is carried along it, and whether it forms part of an escape route. State the fall height so the guard-rail requirement is unambiguous. Give the available support positions and spans.
Five lines, and they prevent the two failures that recur on this kind of work: a route sized to the minimum when it needed more, and a route that measured correctly until the services went in.
Before the route is drawn
Width on an industrial walkway is not really a dimension, it is a consequence of who uses the route and what they carry. The standard supplies a floor rather than an answer, and the difference between the floor and the right figure is usually decided by a conversation with the people who will walk it.
Our engineers will size a route against the actual traffic and the support positions available, and the aluminium industrial walkways and platforms we supply are quoted with the clear width stated as a maintained dimension rather than as an overall one.