Machine guarding is essential for preventing workers from reaching hazardous moving parts, including rotating shafts, rollers, cutting tools, robot cells and automated production equipment. Within the European Union, a compliant machine guard must do more than form a physical barrier. Its openings, location, strength, fixing method and access controls must all be selected through a documented machinery risk assessment.
Mesh aperture size is particularly important. An opening that is safe at one distance from a hazard may allow a finger, hand or arm to reach dangerous machinery when installed closer to it.
EU Machine Guarding Requirements
At present, machinery placed on the EU market is generally governed by the Machinery Directive 2006/42/EC. The new Machinery Regulation (EU) 2023/1230 will replace the Directive and becomes generally applicable on 20 January 2027.
The legislation requires machinery manufacturers to assess risks and apply protective measures according to a recognised hierarchy. Hazards should first be eliminated or reduced through inherently safe design. Guards and protective devices are then used for risks that cannot be eliminated through design alone.
Machinery supplied in the EU must satisfy the applicable essential health and safety requirements before it can be CE marked and placed on the market.
Mesh Aperture Size and Distance from the Hazard
The appropriate mesh aperture depends on the distance between the guard and the nearest reachable hazard. In general:
- Smaller apertures can be positioned closer to the hazard.
- Larger apertures require a greater separation distance.
- Gaps below, above or beside the guard must also be assessed.
- Reaching over, around or through the guard must be considered.
EN ISO 13857 is the principal standard used to determine safety distances that prevent upper and lower limbs from reaching machinery hazard zones. It provides safety-distance values for protective structures in industrial and non-industrial environments.
The standard includes different requirements for regular openings, such as square, circular and slot-shaped apertures. This distinction matters because a narrow slot may permit greater reach than a square opening with a similar nominal dimension.
Mesh should therefore not be selected simply by specifying a common panel size, such as 25 mm or 40 mm mesh. The guard designer must establish:
- The aperture’s actual clear opening.
- The shape and orientation of the opening.
- The distance from the inside surface of the guard to the hazard.
- Which part of the body could enter the opening.
- Whether the guard can deflect towards the machinery.
The applicable EN ISO 13857 tables should then be used to confirm the minimum required safety distance.
Conducting a Machine Guarding Risk Assessment
A machinery risk assessment should cover every stage of foreseeable use, not just normal production. This includes setup, adjustment, cleaning, inspection, jam clearing, tool changes, maintenance and fault recovery.
The assessment should identify:
- Crushing, shearing, cutting and entanglement hazards
- Drawing-in and trapping points
- Ejected parts, materials or broken tooling
- Hot surfaces and process emissions
- Unexpected startup or stored energy
- Access through doors, gates and removable panels
- Foreseeable attempts to bypass or defeat safeguards
The assessment should also account for workers reaching over the top of a fence, crawling beneath it or using nearby equipment as a step.
Fixed Guards and Interlocked Access
EN ISO 14120 specifies general requirements for the design, construction and selection of fixed and movable machine guards. It addresses mechanical strength, securely retained fixings, visibility, durability and the avoidance of additional hazards created by the guard itself.
Fixed guards are generally appropriate where access is infrequent. Where routine access is required, a movable guard fitted with an interlocking device may be necessary. Interlocking systems should be selected and designed in accordance with the applicable machinery safety standards, including EN ISO 14119.
An interlocked gate must stop hazardous machine functions before a person can reach the danger zone. Where machinery takes time to stop, guard locking may also be required.
Treat the Guard as a Complete Safety System
Compliant EU machine guarding depends on more than mesh aperture size. Safety distance, guard height, panel strength, floor clearance, gate interlocking, stopping time and prevention of bypass must function as an integrated system.
The correct approach is to complete the risk assessment first, identify the relevant harmonised standards and then select the guarding system. Choosing mesh based only on price, visibility or availability can leave dangerous reach paths and undermine the machine’s CE compliance.