Reach-through and reach-around hazards occur when a person can access dangerous machine movement through an opening, around the side of a guard, over the top of a barrier or through an unprotected interface. In practice, these terms describe different access paths that must be considered when assessing whether guards adequately prevent people from reaching a danger zone.

A machine can appear fully guarded while still allowing access to rotating parts, nip points, cutting zones, robot movement or crushing hazards. The issue is often not the panel itself. It is the relationship between the opening size, guard position, safety distance and the way people can approach the machine.

Identifying these hazards requires more than checking whether a fence or mesh panel is present. The guarding layout must be assessed from the perspective of an operator, cleaner, maintenance technician or anyone else who may be able to reach the danger zone during normal use or foreseeable intervention.

What Is a Reach-Through Hazard?

A reach-through hazard exists where a person can put a finger, hand or arm through an opening and contact a dangerous part of the machine.

Common examples include:

• Mesh panels positioned too close to rotating machinery
• Large apertures in perimeter fencing
• Gaps around conveyor openings
• Inspection openings without adequate setback distance
• Spaces between guards and machine frames
• Openings around chutes, services or product transfer points
• Unprotected access to pulleys, rollers or drive components

Opening size and guard-to-hazard distance must be assessed together. Larger openings can permit greater reach and may require greater separation from the danger zone.

A common mistake is selecting mesh based on visibility or panel availability, then placing it as close as possible to the machine. That approach can create a guard that looks secure but still permits access to hazardous movement.

What Is a Reach-Around Hazard?

A reach-around hazard exists where a person can bypass the edge of a guard or enclosure and access the danger zone from the side, end or interface.

Reach-around access can occur:

• At the ends of a conveyor guard
• Between a perimeter fence and a wall
• Around a machine frame or support structure
• At the edge of a robot-cell enclosure
• Through an opening created for product flow
• Around panels meeting existing equipment
• Near loading and unloading stations
• At poorly positioned gates or removable sections

These hazards are common on retrofit projects, where new guarding is installed around existing conveyors, columns, platforms, pipework or machinery. The main guard run may be sound, but the surrounding interfaces can leave an uncontrolled path to the hazard.

Why Reach Hazards Are Often Missed

Reach-through and reach-around hazards are often missed because guarding is reviewed from a general layout view rather than from the actual access points available to people on site.

Common causes include:

• Focusing only on the most visible moving component
• Measuring to the machine frame rather than the actual danger zone
• Assuming a standard mesh panel is suitable for every application
• Ignoring access beneath, above or around the guard
• Adding conveyor or product openings after the layout is approved
• Installing perimeter fencing without reviewing surrounding structures
• Relocating gates or panels during installation
• Failing to account for maintenance and jam-clearing tasks

A guarding layout should be assessed from all realistic approach directions. This includes standing, crouching, reaching from a platform or other foreseeable standing point, or accessing the machine from an adjacent conveyor or structure.

How to Identify Reach-Through Hazards

Start by identifying every opening in the guarding system. Do not limit the review to mesh apertures.

Check:

• Panel mesh openings
• Floor clearance below guards
• Gaps between posts and panels
• Corners and panel joints
• Openings around conveyor infeed and discharge points
• Holes or cut-outs for pipes, cables and services
• Inspection ports and viewing openings
• Spaces between the guard and machine frame
• Removable panel interfaces

Then identify the closest point of hazardous movement behind each opening. This may be a rotating shaft, roller, pulley, robot operating space, cutting tool, press point or other danger zone.

The question is not simply, “Can a hand fit through?” It is, “Can any part of the body reach the danger zone through this opening under foreseeable conditions?”

How to Identify Reach-Around Hazards

For reach-around hazards, inspect the outer edges and interfaces of the guarded area.

Review:

• The start and end of each guard run
• Interfaces with walls, columns and machine structures
• Gaps beside conveyors and transfer systems
• Guard ends near loading stations
• Openings beside robotic cells
• Spaces around gates, hinges and latching points
• Clearances around pallet-entry or product-transfer openings
• Adjacent platforms, steps, pallets or stored material

Walk the perimeter and assess whether a person could bypass the barrier without opening a gate or removing a panel.

This should include foreseeable attempts to save time. If operators regularly reach around a guard to clear product, reset a sensor or inspect a process, the access arrangement is not controlling the risk effectively.

Consider Reach-Over and Reach-Under Access

Reach-through and reach-around hazards should not be assessed in isolation. The same layout may also allow access over or under the barrier.

Check whether people can:

• Reach over a low panel or fence
• Climb on nearby equipment, pallets or platforms
• Reach under the guard from floor level
• Use a gap below the panel to access moving components
• Approach the machine from a raised walkway or mezzanine
• Reach through from an adjacent work area

Guard height, floor clearance, nearby standing points and the location of the actual danger zone all matter. A perimeter fence may be high enough from floor level but inadequate when a nearby platform changes the effective approach height.

Modular Machine Guarding Considerations

Modular machine guarding can simplify perimeter layouts, future expansion and replacement of damaged sections. However, standardized panels and posts do not remove reach hazards automatically.

On modular systems, pay particular attention to:

• Standard panel widths that create awkward end gaps
• Post locations near machine frames or walls
• Floor clearance below panels
• Panel joints and corners
• Conveyor penetrations and product-flow openings
• Interlocked gate positions
• Added extension sections
• Changes made during line expansion or equipment relocation

A modular layout should follow the hazard and access requirements, not simply the convenient arrangement of available components. Where a standard panel creates an unsuitable gap or insufficient setback, the layout should be adjusted or a purpose-designed section used.

Standards and Technical Considerations

Reach hazards should be assessed as part of the broader machine risk assessment and safeguarding design.

Common international standards relevant to this work include:

• ISO 12100 for machinery risk assessment and risk reduction
• ISO 13857 for safety distances to prevent hazard zones being reached by upper and lower limbs
• ISO 14120 for the design and construction of fixed and movable guards
• ISO 14119 for interlocking devices associated with guards
• ISO 13855 for positioning protective devices and safeguards where approach speed and stopping time are relevant

In Australia, the AS 4024 Safety of Machinery series addresses machinery safety topics including risk assessment, guarding, safety distances and safety-related control systems. Local regulations and industry requirements should also be checked for the installation location.

Correcting Reach Hazards

The correct solution depends on the hazard and the access requirement. Possible controls may include:

• Increasing the guard-to-hazard distance
• Reducing opening size
• Extending the guard perimeter
• Closing uncontrolled gaps at interfaces
• Adding close-fitting local guards
• Repositioning access gates
• Using fixed panels where access is infrequent
• Using interlocked movable access where regular entry could otherwise expose a person to hazardous machine functions
• Redesigning conveyor or product-transfer openings
• Removing climbing aids or restricting access to raised positions

Do not solve a reach problem by simply adding more mesh without checking safety distance. A guard can still be ineffective if the hazard remains within reach.

Conclusion

Reach-through and reach-around hazards are common ways machine guarding can fail in practice. They often occur at openings, guard ends, conveyor interfaces, corners, floor clearances and surrounding structures rather than in the center of a fence panel.

A proper review should identify every realistic path to the danger zone, including access through, around, over and under the guarding. On modular machine guarding projects, standard panels and gates can provide a practical layout, but the final arrangement still needs to control the actual reach paths created by the machine and site conditions.

If you are reviewing an existing enclosure or planning a new guarding layout, assess the hazard position, opening sizes, access tasks and surrounding interfaces before finalizing panel locations or gate positions.

Frequently Asked Questions

What is a reach-through hazard?

A reach-through hazard occurs when a person can put part of their body through an opening in a guard and contact a dangerous machine part or danger zone.

What is a reach-around hazard?

A reach-around hazard occurs when a person can bypass the side, end or interface of a guard and access a danger zone without opening the intended access point.

Can mesh guarding still allow access to hazardous parts?

Yes. If the mesh opening is too large or the guard is too close to the hazard, a person may still be able to reach through and contact moving parts.

How do you prevent reach-around access?

Reach-around access can be reduced by extending the guard perimeter, closing gaps at walls and machine interfaces, repositioning panels or gates, and reviewing nearby structures that may allow access around the barrier.

Do conveyor openings create reach hazards?

Yes. Infeed, discharge and transfer openings are common locations for reach-through and reach-around hazards. They should be assessed against the actual hazard location and required safety distance.

Does modular machine guarding eliminate reach hazards?

No. Modular machine guarding can support a practical layout, but panel joints, end gaps, floor clearances, gate positions and transfer openings still need to be designed around the actual hazard and access path.

When should reach hazards be reviewed?

Review reach hazards during initial guard design, before installation, after commissioning and whenever machinery, conveyors, access points or surrounding layouts change.