Intelligent Safety Design Improves Productivity

Ask any food production line manager about the importance of safety, and he will likely tell you about the critical role it plays in protecting personnel, reducing injuries, and meeting compliance demands. These are all valid objectives, but food processors, packaging companies, and machine builders are missing opportunities to respond to the challenges of global consolidation and changing consumer preferences if they only focus on avoiding negative consequences. Instead, they should view safety as a catalyst for greater performance: increased productivity, improved competitiveness, and overall profitability.

Historically, the food industry has viewed safety practices as punitive actions or compliance activities, not as opportunities to deliver real value or to gain a competitive edge. These days, however, food processors and packaging companies understand that a well-designed safety system will improve efficiency and productivity. Machine builders recognize that safety systems will improve both business and machine performance—and help differentiate them from their competitors.

The combination of functional safety standards, new safety technologies, and innovative design approaches is positioning safety as a core system function that can deliver significant business and economic value, with financial returns beyond the benefits of reducing the costs associated with accidents and medical expenses.

As part of the Rockwell Automation Integrated Architecture system, the Compact GuardLogix controllers use the same configuration, networking, and visualization environment as the company’s larger-scale systems. This helps provide cost-effective integration of a machine or safety application into the plant-wide control system.

A Systematic Approach

To achieve a higher level of functional safety and to gain real benefits, system designers must have in-depth understanding of food processing and packaging procedures and a clear determination of machinery limits and functions. They must also possess a thorough knowledge of the various ways in which people interact with the machinery. They should take a practical, rigorous approach to safety system design and be willing to implement and apply new safety technologies and techniques.

The functional safety life cycle, as defined in standards IEC 61508 and IEC 62061, provides the foundation for this detailed, more systematic design process for machinery applications. A key objective of the safety life cycle is to address the cause of accidents. To do this, designers want to create a system that will reduce and minimize risks, meet appropriate technical requirements, and ensure personnel competency. Previous standards have relied on prescriptive measures defining specific safeguarding.

The new functional standards are performance based, making it easier for designers to quantify and justify the value of safety. This approach is more methodical and deterministic, with the ability to tailor specific safety functions to the application. It helps reduce cost and complexity, improves machine sustainability, and enables an optimum level of safety for each defined safety circuit or function, thus improving return on investment.

Phases of Safety Life Cycle

Conducting a risk assessment is the first phase of the safety life cycle. A risk assessment provides the basis for the overall risk-reduction process, which involves the following steps:

• eliminate hazards by design using inherently safe design concepts;
• employ safeguarding and protective measures with hard guarding and safety devices;
• implement complementary safety measures, including personal protective equipment; and
• achieve safer working practice with procedures, training, and supervision.

In safety system design, a risk assessment can help identify potential hazards and the safety mechanisms needed to ensure adequate protection from those hazards. The functional life cycle provides the framework for several highly effective “design-in” safety concepts. These include passive, configurable, and lockable system designs.

A passive approach is based on the philosophy that safety systems should be easy to use and should not hinder production. Operators may decide to bypass safety systems if they are cumbersome or impractical or do not easily accommodate maintenance and operating procedures.