OpsManage / Safety Instrumented Systems / Systems Integration / Asset Management

Of Swiss Cheese, KPIs and Process Safety

How to Find Out How Safe Your Operations Really Are

By Nancy Bartels

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"How safely is my plant operating? How do I know? How does my plant's safety compare with other company plants? How does it compare across regions?" These are fundamental questions raised by Ajay Mishra, R&D program manager for Invensys in a presentation on functional safety and process safety management this week at the 2013 Invensys Foxboro & Triconex Global Client Conference in San Antonio, Texas.

Following the old rule that if you can't measure it, you can't control it, Mishra outlined a methodology for quantifying the performance of individual assets, departments and plants that can reveal to business managers just how well their plants are performing in terms of safety. The goal is to move plant management beyond the practice of occupational and functional safety to the wider view of process safety management (PSM).

Mishra defined PSM this way: "The application of management systems to the identification, understanding and control of process hazards to prevent injuries and incidents. The goal is to minimize process incidents by evaluating the whole process."  

This wider view is important because all too often, "process safety management is addressed only after an accident happens," said Mishra. "What's missing is the ability to provide plant personnel with real-time, pro-active actionable information of a plant's risk profile via continuous measurement, monitoring and visualization of key operating and safety-related parameters so that potentially hazardous events can be averted without the need to resort to a plant trip or emergency shutdown."

Mishra demonstrated the importance of the consistent, constant monitoring by showing the "Swiss cheese" hazard model. Each layer of protection for a particular process has "holes" in it—the residual risks. The problem occurs when the holes in the various layers line up, creating a hazard. Worse, the actual risk can increase over time if the safety management is insufficient, and "a larger hole equals increased risk of an incident," says Mishra. The goal of a process safety management system is to keep those risks at their designed level, or put another way, keep the holes small and not lined up with one another.

The first step in building a process safety management program—one that will speak the language of business managers—is gathering key performance indicates (KPIs), beginning at the asset level. There is no one-size-fits-all list available. Each plant must determine what measures are important to its individual safety and what its acceptable levels of risk are.

Typically, 10 to 20 key metrics can cover management of safety-related equipment, competence of plant personnel, adherence to established procedures, and leadership. These KPIs are then aggregated, by means of a series of equations, into a single number, the safety performance indicator (SPI), which can be calculated at both the equipment level and the plant level.

The goal of gathering all this information and implementing a PSM system is to create a "closed-loop for safety," said Mishra. The plant feeds information in the form of KPIs on individual assets, preferably in the form of dashboards that can show current status and progress at a glance, to their operators and department managers, and these are compared against the benchmarks and designed-in risks, and that information is fed to management, who can then go back to the plant with recommended changes and modifications in practice, if necessary. Everyone all the way up the line has near real-time information about plant safety.

"I think the business case is important, and the concept of incremental value-at-risk (asset value, production quantity, revenue) tries to bridge the process safety metrics to the business side," concluded Mishra. "Investments in a PSM system may be made if it can be shown that it delivers a significant, tangible reduction in the risk of a catastrophic failure, as well as produces a measurable economic benefit for the plant."