Safety Drives Paradigm Shift: Turning an expense into a benefit

J.B. TITUS - Manager, Business Development and Industry Standards, Siemens Energy & Automation, Inc.

Manufacturers and suppliers no longer view enhanced safety in the workplace as an unwelcome expense—a paradigm shift that has been going on for 30 years.

By understanding the evolution and current state of machine design safety standards and technologies, companies in Europe, Canada, and the United States are reaping the benefits of integrating safety into their operations. As international trade barriers continue to shrink, these standards and technologies will not only protect workers in more parts of the world, but will decrease operating and liability costs for manufacturers.

In addition, the expanding market for integrated safety worldwide has made machine safety an economic imperative. ARC Advisory Group's 2005 Machine Safeguarding Solutions Worldwide Outlook report states that the global machine safeguarding market is growing at twice the rate as the automation market—approximately 8.4% compound annual growth rate through 2009. This is a direct result of the changes in industry safety standards in combination with technological innovations.

The Shift Begins

The worldwide shift to embracing machine safety began 30 years ago with the advent of PLC technology.

The move from relays to PLC control, originally known as an automatic sequencer, changed the way engineers designed and wired machines. However, the automatic sequencers of yesterday were unreliable, especially when compared to today's PLC technology. As a result, European and North American regulators excluded PLCs from machine safeguarding systems.

Moreover, very little attention was paid to protecting workers on assembly lines or other manufacturing operations with machines from multiple vendors. As the emergence of "local" safety regulations increased, end users had no choice but to add safety devices to existing machine control systems. Safety was an afterthought and usually interfaced to the existing machine control (see Fig. 1).

For example, a metal forming company may have had six stamping machines connected together. Parts were transferred from one machine to another to progressively form the product. However, because the machines were built by different vendors, many from different parts of the world, there were no consistent standards in place for machine design safety. Ultimately, it was the end user, or manufacturer, who was responsible for worker safety.

In the 70s, 80s, and 90s interfacing multiple safeguarding technologies also became the source of intermittent machine downtime issues impacting production schedules. Specifically, combining multiple interfaces and electromechanical components has helped increase safety measures. It has also caused numerous machine downtime issues.

Over the years, recovery measures have often made matters worse by partially bypassing the functional safeguarding system for the balance of the production shift or longer.

Workers compensation groups around the world were confronted with increasing injury rates. Almost overnight, a wide array of local standards emerged from different countries addressing machine design safety. Simultaneously, companies continued to build manufacturing plants in multiple countries. As international trade barriers grew smaller, end users wanted machines with a common design from multiple vendors and countries.

It was difficult for machine manufacturers to comply with all the different safety and performance requirements emerging around the world.

Solution Harmonizes Standards

The answer to these safety standard, manufacturing, and liability problems began in the mid-1990s, when regulators worldwide began harmonizing standards, including IEC 61508, EN 954-1, IEC 62061, IEC 60204, and EN/ISO 13849-1. Logically, this harmonization push began in Europe since the machine tool industry was born in there early in the 19th century.

A major reason for harmonizing standards was the improved reliability of machine electronics when PLCs were first introduced. Now, electrical control components of machines can play a role in machine safety.

These changes have also facilitated improvements in the supply chain and end user communities. Rarely has industry been able to comply with revised regulations and benefit from documented life cycle cost savings.

Today, safety design is moving from being an afterthought (interfaced) to a forethought (integrated) among machinery manufacturers and end users (see Fig. 2). No longer is the safety knowledge base found primarily with electrical and mechanical maintenance engineers, machine installers, and system integrators. Expanding this knowledge base throughout the enterprise is important for everyone in the supply chain and the end user communities.

Over the past three years, Siemens has participated in market analyses evaluating changes in human behavior brought on by these new machine safeguarding options. More than 100 customer engagements were evaluated. We developed a model to describe the major stages and time lines customers experienced going from "awareness" to "execution" (see Fig.3). One conclusion from this model shows that educational campaigns need to be developed and executed by the supply chain in order to reach the adoption stage with the end user.

People cannot be motivated to perform if they cannot meet the demands of their jobs. Even skilled and motivated people need adequate tools for optimal execution. The most important contribution of integrating safety onto the plant floor is taking safety compliance engagement from an afterthought to the forefront of enterprise infrastructures. Therefore, every level of the typical enterprise must address an educational campaign approach as indicated in Fig. 4.

Another market survey involving 469 companies was jointly conducted in the U.S. by Machine Design magazine and GrowthPoint Inc., in November, 2004. This survey highlighted the need for educational campaigns regarding any changes to safety standards. Furthermore, the survey pointed out that everyone at every level must be included when these new approaches to machine safeguarding are considered (see Fig. 5).

We are now experiencing a second paradigm shift in the world of factory automation. The way is being paved to change how we will design and wire machines. Hardwired and software devices, such as safety PLCs, can be used in safety applications. These devices are designed and built to international standards and must be tested by independent laboratories for compliance.
Because safety standards are now harmonized and electrical technology has improved, machine designers and management can enhance safety compliance and increase profits at the same time. The benefits are numerous:

• Losses from accidents can be reduced
• Increased machine up time is possible by reducing conventional components and home run wiring approaches
  
• As safety functionality is built into safety rated devices, significant cost can be removed from a control system while improving the reliability of the safety design and providing diagnostics to troubleshoot the safety system

In addition, the life of a firmware/software based safety relay with built-in diagnostics is much longer than electromechanical devices. There are no mechanical springs to break or the chance for welded contacts.
The impact of embracing and harmonizing international safety standards, and safety control advancements, is significant. The results include improved employee safety and higher profits for industries around the globe.

For related information, please go to automation.usa.siemens.com/automat/product/safe/auov.html.