Safe by design

Responding is Shawn Mantel, CEO/sales engineer, PowerSafe Automation, Wolcottville, IN.

Implementing effective machine guarding in your facility can be challenging because the word “effective” introduces many factors to evaluate. Designing the proper safety guarding brings a lot of ambiguity into play. When facing a potentially hazardous condition, engineering out administrative tasks to minimize or eliminate human decision-making is recommended. This type of solution focuses on hazard mitigation protecting the operator from access to the hazards – not functional safety with control upgrades. To achieve this, you must assemble a controlled team of individuals focused on safety as the goal, both internally and externally, creating a plan of attack formulated by the steps listed here.

Starting from a place of hazardous condition on a machine already identified for mitigation, the initial step in ensuring you’ll have effective machine guarding is to find the right machine safety company that checks all the boxes for you. Ask qualifying questions such as:

• How are they qualified to help us?
• Do they offer turnkey solutions?
• Are they willing to collaborate with us on the designs?
• Are their solutions diversified?
• Do they have the proper liability insurance?

The next important step in a successful guarding package is conceptualizing while evaluating the hazards. The easy fix for any supplier is to build a box around the machine and put a padlock on the access point to eliminate the hazards, but this doesn’t work for the customer. Involve operators and maintenance in the process, combining their knowledge of machine safety with machine operational functionality. Their insight will prove to be impactful in helping to creatively design custom, user-friendly guards.

This is the point where the details of discovery are used to create a practical and functional guarding system. A properly engineered system consists of three things: physical guarding where frequent or repetitive access isn’t required, electronic safety devices for presence sensing with proper machine stop time, and the proper safety monitoring devices. Constructing detailed drawings with the right products for the application, a detailed scope of work, and a reference back to each machine will create clarity for the operators and maintenance team during the approval process.

Although safety is always a priority, downtime is typically a concern because of capacity issues. However, rushing the process of improving safety shouldn’t be forced. A key process is to have the guarding fabricated and built offsite to reference only drawings, leaving “tweaks” for the installation process. This allows for improved efficiencies through tooled assembly stations, quality control processes, bench testing of field devices and easy access to engineering verifications, contributing to downtime if these tasks are executed onsite.

Once the project builds are complete, the installation can be scheduled, which is highly recommended to be done when the operators are present. This will help with any questions or interpretations required throughout. When installing the guarding, a dry fit is a great first start, allowing operators time to review for any operational feedback. From there, the guarding can be fastened in place to the floor and/or machine, ensuring proper rigidity as well as adding strategic impact barriers such as corner bollards.

The machine guarding is now ready for the integration of the e-safety devices. These devices should be installed with tamper-resistant screws, cables secured and an isolated safety circuit enclosure allowing for ease of troubleshooting. A vital part of the integration is the maintenance tech being able to collaborate with the contractor’s controls engineer to trace the proper termination points, resulting in the desired stop behaviors.

The installation of the machine guarding doesn’t complete the cycle of effectiveness. Longevity is a key factor in maintaining the functionality of the guarding system. As part of the commissioning process, an overview of the machine guarding, including how the e-safety devices interact with the machine, should be performed between the contractor, the operator and the maintenance team. This will help identify any issues that may arise through wear and tear or environmental abuse.

The final part of extending the life is preventive maintenance. Tires are rotated, belts are tightened, wheel bearings are repacked, and motor oil is changed all on a regular basis as good practice to extend the life of the equipment.

Implementing effective machine guarding in your facility can be overwhelming with the number of steps, required expertise, and how the dots are connected for efficiency and communication. With the right mindset, the correct team – internally and externally – and the appropriate products, you can work toward a safer work environment for your employees.

Editor's note: This article represents the independent views of the author and should not be considered a National Safety Council endorsement.