Machine guarding is often viewed as a physical barrier between a worker and a moving part. Fixed metal guards, fencing, or interlocked gates that physically keep employees away from hazardous motion are often the first things that come to mind. These safeguards are essential, but they are not the only options.
In modern manufacturing, warehousing, food processing, and industrial operations employees may need frequent access to load parts, clear jams, or inspect products. In these situations, machine guarding must protect employees without creating unnecessary production bottlenecks.
Although physical guarding can work, especially when designed with methods for easily accessing the parts when needed (e.g. pins and hinges that don’t require a full guard removal), this is where non-barrier safeguarding devices can play an important role. These technologies do not physically block an employee from reaching the machine. Instead, they detect presence, interrupt hazardous motion, and help reduce exposure.
Safety Light Curtains: Invisible Machine Protection
A safety light curtain uses a transmitter and received to create an invisible sensing field typically made up of infrared beams. When a body part or object interrupts the field, the safety system sends a stop signal to the machine control circuit.
When properly applied, light curtains can protect employees while preserving visibility and access at loading stations, press operations, robotic cells, automated assembly equipment, and packing lines. Light curtains are especially useful where operators need to access the point of operation repeatedly and a fixed guard would be impractical.
However, light curtains aren’t a universal solution. Key considerations for this application include:
- Stopping time: The machine must be able to stop before an employee can reach the hazard after breaking the sensing field.
- Safety distance: Installation must account for approach speed, system response time, and machine stopping performance.
- Application type: Finger, hand, arm, and object detection require difference device resolutions and mounting strategies.
- Bypass prevention: Employees should not be able to step around, reach behind, or otherwise avoid the protected field.
- Environmental conditions: Dust, vibration, reflective surfaces, moisture, and alignment issues can affect performance.
- Validation and maintenance: Devices must be tested, inspected, and documented as part of the facility’s safety management system.
Safety Mats for Presence Detection
Safety mats are pressure-sensing safeguarding devices installed on the floor around a machine, robot cell, or hazardous area. When a person steps on the mat, the safety circuit detects the presence and initiates a stop or prevents the hazardous motion from starting.
Unlike a fence or fixed guard, a safety mat does not block entry. Instead, it detects when a person is present on the mat and helps control the machine response.
Safety mats can be effective in larger access zones, operator work areas, robot perimeters and equipment where whole-body presence detection is needed. They can also be useful where line-of-sight sensing is difficult or where an employee may enter a zone and remain there.
Like other machine guards, safety mats must be selected and installed with the work environment in mind. Main decision criteria for installing safety mats include:
- Coverage area: Mats must cover the realistic approach path into the hazard zone.
- Response time: The safety system and machine must respond before an employee can reach hazardous motion.
- Reset strategy: Restart should not occur automatically simply because the person steps off the mat.
- Durability: The mat must be suitable for expected traffic, contaminants, cleaning practices, and floor conditions.
- Trip hazards: Edges and transitions should be managed to reduce slip, trip, and fall risks.
- Inspection: Facilities should routinely test mat function, cable integrity, and control reliability.
- Operating conditions: Some safety mats can have reduction in use time depending on the environment.
Machine Risk Assessments Guide Safeguarding Decisions
The Occupational Safety and Health Administration’s (OSHA) general machine guarding requirements emphasize protecting employees from machine hazards through appropriate guarding methods. Meeting these requirements is essential for employee safety, operational efficiency, and regulatory compliance.
Before installing any machine guard, your equipment should be evaluated to determine safety needs. The machine, task, employee interaction, control system, energy sources, maintenance needs, and foreseeable misuse should be considered in the initial assessment. A safeguard that looks effective on paper may fail in practice if it is installed too close to the hazard or without normal operation in mind. It is currently seen that large robust machine safeguards are implemented, but regularly removed or bypassed because they interfere with operations or maintenance, or are otherwise not seen as a priority by operation supervisors.
An experienced safety consulting firm like Conversion Technology, Inc. (CTI) can help your facility move beyond one-size-fits-all guarding decisions. Technicians can identify machine hazards, evaluate existing safeguards, review employee tasks, recommend appropriate guarding options, and help develop practical corrective actions that align with operations.
Choose the Best Machine Guarding Solution
Whether you are upgrading older equipment, adding automation, responding to an incident, preparing for an inspection, or building a proactive machine safety program, the right safeguarding strategy can reduce risk without unnecessarily slowing production.
Start with a machine-specific risk assessment with a qualified consulting firm like CTI. Our experienced team can help you evaluate hazards, compare safeguarding options, and develop practical recommendations for employee protection, compliance, and operations efficiency.
We have extensive experience working with in-house maintenance or outside fabrication teams to design, fabricate, and install site- and operation-specific guarding that reduces potential employee exposure to hazards while minimizing any potential interference with operational applications.
Contact us today to get started on your facility’s next machine guarding project.