Robotic Guarding: Safety Mats Versus Safety Fencing

Robots move quickly, creating a risk of hitting anyone nearby, a product coming loose from the robot’s gripper, or the gripper detaching from the arm. To prevent accidents around automated equipment, the usual practice is to keep workers away from hazardous areas, which is usually accomplished with fencing. However, there may be certain processes requiring frequent access to the equipment, or where fencing reduces visibility in ways that cause problems. In these situations, other technologies, such as safety mats, may be helpful.

Conducting Risk Assessments

Before we discuss the differences between mats and fencing, we want to emphasize the importance of performing risk assessments because this is going to be the only way you’ll know whether each option is enough to address the risks unique to your workplace.

Ideally, a risk assessment is performed during an automation project’s design phase, but it should be repeated after implementation and commissioning, and whenever any aspect of the facility layout or workflow changes.

Safety Mats

A safety mat is a large pressure switch that’s placed on the floor. It’s typically made from a rugged elastomeric material and features integrated metal plates.

When a load is placed on the mat, the plates come together, completing an electric circuit that sends a signal to a safety controller. From here, if a load is detected on the mat, the controller stops cell movement.

Safety mats, which should comply with the ISO 13856 standard, are designed to operate at pressures over 45 pounds. A key consideration when placing safety mats around automation is distance. They must be far enough away from the hazard that motion stops before someone could cross that mat and put themselves in danger.

It’s also important that no gaps are left around the equipment where someone could cut through.

Advantages

• No physical barriers to movement
• Easy to deploy/minimal installation and setup needed
• Provide a visual indication of the hazard areas around the equipment

Limitations

• Can be accidentally triggered
• Does not stop or catch anything flying away from the automated equipment
• Requires significant floor area to provide the necessary safety distances
• Can be damaged by heavy equipment or chemicals
• Tend to wear out with intensive use
• Can create a trip hazard

Best Use Cases

• Around equipment where operators need regular access for loading/unloading
• In cells where workers will need to move past equipment that could be hazardous
• Situations where protection is only needed short-term (e.g., machinery implemented for a single project and then shipped out again)

Safety Fencing

Safety fencing is constructed with vertical panels (made from a variety of materials), secured to floor-mounted vertical posts, and placed around the automation equipment or robot cell with hinged or sliding gates. These gates use interlock switches that connect to the automation or safety controller, killing motion when they are opened.

Most safety fencing panels are mesh within a solid outer frame. The size of the mesh determines the largest object that can pass through and establishes the distance required from the moving equipment. Fencing is also colored a highly visible yellow, although other options are possible.

If machinery or industrial robots release dust, liquids, or other debris, mesh panels can be replaced with transparent or solid panels.

Advantages

• Provides a physical barrier that prevents access to working equipment
• Minimizes floor area needed for safety protection (sliding rather than hinged gates further support this goal)
• Prevents risk of injury due to flying materials (and dust and debris, if solid panels are used)
• Robust and requires very little maintenance
• Can be moved and repositioned if the robot cell is altered

Limitations

• Restricts access to the machinery being guarded
• Can reduce visibility into and around the cell

Best Use Cases

• Robotic cells where workers need protection from moving equipment
• Preventing access to automated industrial equipment (and other areas of the factory, if needed)
• Situations where space is limited, but workers must be protected from industrial machinery
• Providing permanent, robust safety barriers

Learn More From ROBO FENCE

ROBO FENCE® supplies rugged, OSHA-compliant safety fencing for robotic cells, manufactured by our partner, Square Group. Our specialists can help you identify the best safety solution for your facility based on your risk assessment and provide design consultations as needed.

Visit our website to learn more about our capabilities, or contact us today to speak with a specialist.