Whether you're a weekend runner gunning for a 5k personal record or an aspiring Olympian with her eye on the medals stand, understanding one's current capabilities is a necessary first step in realizing one's athletic performance goals. Similarly, the first step in achieving—or restoring—the performance of your plant's safety systems begins with a cold-eyed assessment of their current capabilities. Only then can you begin to develop a plan to bring your safety systems to the desired level of performance.
The previous article in this special report ("The Safety Fitness Test"), discussed how to go about assessing the current risk-reduction capabilities of your plant's safety systems, and identifying gaps relative to goal. In this article, we'll focus on applying new safety system technology as a first step toward bringing performance back up to speed.
Among the first go-to solutions in the runner's toolkit is an upgrade to supporting systems and technology—notably new shoes or technical clothing, perhaps the purchase of a new GPS watch or even the hiring of a new coach if funds allow. True, money alone won't solve your fitness problems, but it's hard to focus on building new speed when shin splits or chafing forces you off course, or you can't tell just how fast or how far that last tempo run was. Similarly, your safety fitness assessment may have pointed to the need to update the plant's safety instrumented systems. Choose the right supplier and engineering partner carefully to make sure this project is off on the right foot from the very start.
'Proven in Use' Compliance
One of the key advances in safety systems practice promulgated in the IEC's 61508 and 61511 safety standards is the primacy of functional safety management systems (FSMS) for all organizations involved with safety instrumented systems work. This includes those organizations manufacturing the hardware and developing the software; those organizations engineering, installing, testing and validating them; and those organizations operating and maintaining them.
If your plant's safety systems were developed and installed under the aegis of the 61508 and 61511 standards, it's likely that standards compliance was mandated at the project stage. This means that the systems and instruments themselves—as well as the development and engineering organizations behind them—were certified by a third-party agency to conform to the standards.
But for systems that predate the 61508 and 61511 standards (and necessarily their certification to them), standards compliance dictates that users demonstrate safety performance by "proven in use" criteria. This non-trivial task may include retroactively demonstrating the adequacy of the manufacturer's quality management systems in use at the time, a thorough inventory and description of systems components and sub-systems currently in use, and demonstrated performance of these components and sub-systems in similar operating profiles and physical environments. This accumulation of documented evidence must adequately demonstrate that your plant's safety instrumented functions (SIFs)as implemented meet the current safety integrity level (SIL) requirements of your process.
Further complicating the risk profile of older safety instrumented systems is the spreading obsolescence and scarcity of system components, and shortage of personnel qualified to work with them. Indeed, many systems currently in use are beyond their supplier's stated support terms. As a result, "proven in use" compliance or the grandfathering of an older system may be an adequate near-term plan, but continued safety performance will require that many of industry's safety fitness plans incorporate a full system update or upgrade in the not-too-distant future. Indeed, a recent report by the ARC Advisory Group indicates that some two-thirds of the safety systems in use today are at or near the end of their supportable lives.
System Update Considerations
For process plants with older safety instrumented systems, then, the outcome of any responsible safety fitness assessment and planning process is likely not whether to upgrade, but the timing of the inevitable. In the real world, of course, replacing a dated or soon-to-be-obsolete system must take into account risk factors but also financial, production and other resource constraints. But with the decision to upgrade finally made, users face quite a different technology landscape than even 15 years ago.
Today, the bid specifications for more and more new plants include not only compliance with the IEC 61508/61511 standards but also "integrated safety" as a base requirement. While at first blush this contradicts long industry practice of ensuring diversity by physically separating safety systems from basic process control systems, new technology together with users' desire to reduce costs and improve productivity are fueling an industry-wide movement to integrated systems.