A well defined risk management program should take a broad approach and consider all aspects of safety throughout a facility, including machine, process, electrical and IT. A formalized program begins by following a complete Safety Life Cycle – as defined in standards IEC 61508 and IEC 62061 – which provides a detailed, systematic design process for machinery applications (see Figure 4).

Conducting a risk assessment is the first phase of the Safety Life Cycle. A risk assessment helps determine what potential hazards exist and which safety mechanisms should be implemented to help ensure adequate protection. It provides the basis for the overall risk reduction process, which involves the following steps:

• Reduce the risk of hazards by using inherently safe design concepts

• Employ safeguarding and protective measures with hard guarding and safety devices

• Implement complementary safety measures including personal protective equipment (PPE)

• Help achieve safer working practices with procedures, training and supervision

“When assessing risk, it is critical to identify the tasks people perform, and what actions need to be taken for those tasks to be performed more safely,” said General Motors’ Douglas. “From there, designers can look at those same tasks and determine how much time they require, and how that time impacts production throughput.”

Using this approach in the mid-1990s, for example, General Motors saved several million dollars per year across five plants by installing safety controls for critical and routine production tasks. The company also completed a risk assessment on its new Volt electric vehicle, and saved $350,000 the first year by changing the way it put caps on the battery insulation posts.

After a risk assessment, the designer will define the functional requirements of the machine and begin designing the safety system. The next step is to verify and validate the performance of the safety system design. The final phase in the life cycle is to conduct maintenance on the machine as needed and make future improvements as new technologies become available.

Figure 4