Safety first: Put up your guard

05/01/2013


At-risk equipment

When the client launched its 2009 zero-fatality program, there were company manufacturing facilities with equipment that required updating to meet new occupational and machine safety standards. Additionally, multiple original equipment manufacturer (OEM) safety systems existed; therefore, the implementation of safety standards was inconsistent.

As part of its strategic plan, the company partnered with preferred vendors to assist with a company-wide risk mitigation of its equipment.

The client’s dedicated safety team developed standards of safety for all equipment, which included:

  • Conforming to safety categories based on the risk assessment, maintenance standards, operational consistency, and troubleshooting procedures
  • Preferred vendors, such as Polytron and E2M, were selected to support the safety initiatives. Selection was made based on the vendor’s critical understanding of how the risk assessment translates into applied machine safety systems to lower the risk score.
  • Training meetings were held with preferred vendors, key technology suppliers, and OEMs to share the new standards and requirements to support the machine safety initiative. Those trained were then brought alongside the safety team to provide support in the risk mitigation effort.

Risk mitigation for older equipment

JB Titus and Associates portrays the Risk Reduction process depicting the tolerable risk scenario most typically followed to determine if the risk is acceptable or requires some action for risk mitigation. In the case study here, a risk assessment was conMachine safety modifications are typically conducted in one of two ways. With new equipment, the modifications are designed into the equipment; for older equipment, either in-depth modifications are required to the controls or modifications are added onto the equipment.

Based on the new safety standards, the safety team began the risk assessments for existing equipment to identify the greatest risks that required mitigation. Polytron and other strategic technology partners provided support for the risk assessments.

Some OEMs, who originally provided the older equipment, were contacted to assist in the safety modifications. What Polytron found was that due to the extensive changes to be made to the equipment, it would be cost prohibitive to use the original OEM.

Oftentimes, the OEM needed the equipment shipped back to its facility to perform the upgrades, an alternative that would not be considered due to the increased loss of production and costs. The manufacturer decided the best option was to engage Polytron and its partner E2M to execute the more engineering-intensive machine safety upgrades for older equipment, some of which was more than 20 years old.

Older equipment presents more complex issues, such as legacy control architectures that can’t support new safety technology, outdated utilities, and the constraints of other systems that interface with the equipment.

These factors challenge the project team to understand and define the full scope and scale of what is needed. Definition is difficult due to the unknowns that will likely be uncovered as the project begins. It is extremely important to have a thorough plan identifying all possible contingencies in each area prior to beginning the work.

Machine safety projects are more successful when a systems integrator with machine safety expertise is involved. This expertise allows the manufacturer to realize benefits such as:

  • Understanding of standards and how to effectively apply technology.
  • Minimized machine downtime and impacted systems due to a well-developed plan.
  • Cost-effective changes that reduce the risk level of the equipment within company allowable limits.
  • Increased equipment efficiency in most cases.

Machine safety upgrades offer an opportunity to address operational efficiency as the safety project requires a complete overhaul of older equipment. While the client may not use the project to increase efficiency, the safety initiative often results in improvements.

This is effectively measured in reduced mean-time-to-repair (MTTR). Since the equipment now has isolated safety/operational zones, repairs to the equipment or clearing faults can be accomplished in the affected zone without impacting the operation of the rest of the machine.

High risk palletizer area

Risk assessments targeted the palletizer area as a higher risk area for a stand-alone safety project. Polytron conducted the project in collaboration with its partner E2M. Consistent with Polytron’s machine safety mitigation approach, Polytron and E2M began to conduct the remediation process on the equipment in the palletizer area based on the company’s risk assessment.

The team reviewed the risk assessment provided and began the task of identifying the modifications to lower the risk level of each hazard to bring it within the company’s stated range of tolerance.

A functional specification was developed by Polytron and E2M addressing the specific areas identified in the risk assessment and presented the recommended modifications to the customer. The goal in the functional specification was to adjust and modify to lower the risk level on each area and ensure that changes did not inhibit machine operation. The modifications also provided a consistent system with machine safety engineering and standardized automation, reducing downtime and increasing availability to diagnostics.

The Polytron and E2M team reviewed the design, plan, and cost for the entire project and upon approval from the manufacturer began work.

Safety implementation

Scheduling the implementation of the machine safety project requires extensive coordination due to the evident downtime of the equipment. Older equipment requires considerable updating to bring into compliance and can incur as much as two to four weeks’ downtime based on project complexity.

With machine safety mitigation, it is a trade-off between the cost of new panels and components versus lost time in production to modify existing controls. In this case, the client was fortunate to have parallel systems that provided alternative routing for the line to minimize the production impact. In most cases, the equipment safety upgrade project impacts the entire line with unavoidable downtime.

The total project included:

  • Applying standard controls software components, provided by the customer, including state machine and PLC program templates, and standard HMI faceplates
  • Adding technology as an enabler: Safety-rated components such as safety PLCs, contactors, switches (interlocks), VFDs, light curtains, door switches, e-stop push buttons, and safety rated sensors
  • Creating isolated safety zones to more efficiently operate and maintain equipment.

Equipment updates and modifications were completed and validation and start-up were coordinated with the client. Validation of the technology and physical machine guarding were checked and verified for machine safety compliance, and risk mitigation was finalized in documentation.

Safety climate change, training

Risk mitigation creates necessary change for everyone’s protection, and, in many cases, provides operational improvement. For operators, a machine that has been upgraded with new safety features should be approached as new equipment—machine operations and maintenance has changed, the HMI is new, the logic is different, and new technology has been added. The updates create the need for training and documentation to ensure safety upgrades deliver the intended outcome.

As a result of the changes made to the equipment for our client, new manuals were generated outlining new safety procedures and changes in operator tasks. Polytron’s training team conducted specialized safety training for the updated equipment. For instance, procedures for isolating hazards within a safety zone changed. Isolated safety zones enable the operator to stop the impacted area, access the jam and remove blockage, and restart the isolated zone.

Without training, the operator would continue to shut down the equipment as before, creating unnecessary downtime. Technology transfer and training is critical to the success of risk mitigation projects, for continuity of performance and increased safety of operations.

Palletizer machine safety upgrade

Equipment risk levels in the palletizer area were reduced to an acceptable level. This required applying guarding, new software, safety-rated components, and technology, and creating isolated safety zones for efficient operation and maintenance.

Training was conducted on the new machine operation. As a result, the workforce has integrated the new safety procedures and functionality into the regular maintenance and operation of the system.

This client continues to rely on Polytron and its partner E2M to execute machine safety projects identified in the risk assessment as the company’s EHS program progresses and other upgrades arise based on capital improvements involving targeted equipment.

Based on the company’s 2011 Sustainability report, since the initiation of the machine safety program in 2009, the company reported zero fatalities in 2010 and 2011. Also 69% of the major findings from the global assessments have been closed; 95% of the corrective action and preventive action from fatalities have been closed.

- Sean Daswani, PE, is senior electrical engineer, Polytron. Edited by Mark T. Hoske, content manager, CFE Media, Control Engineering and Plant Engineering, mhoske(at)cfemedia.com

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Read the related Control Engineering blog post: Is OSHA okay with my 'acceptable' risk mitigation?

Polytron provides more about machine safety culture change.


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Mohammed , Non-US/Not Applicable, United Arab Emirates, 05/08/13 12:04 AM:

1. Very Good subject.

2. Needs a specific training program.

2. What about ESD
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