The first step in any athlete's performance improvement plan is a thorough assessment of his current fitness level. The baseline abilities of muscle, heart and lung must be evaluated—perhaps in consultation with a medical specialist—to establish the baseline readiness of core systems to respond to new training demands. Our runner's current fitness level, together with his ultimate performance goals, will identify the gaps to be addressed through an updated training plan.
In the case of our plant's safety systems, the assessment phase begins with a thorough updating of process conditions and risk factors. Safety fitness (risk reduction) goals should take into account the plant's latest key performance indicators (KPIs) in the form of production rates, quality standards and environmental measures as well as any configuration changes that may have impacted the safety system's ability to effectively reduce risk.
Get Up to Speed on Industry Standards
Next up for our runner is a review of the latest training methodologies, which for our plant's safety instrumented systems means the IEC's 61508 and 61511 standards and other applicable codes. Importantly, some two-thirds of safety instrumented systems in use today predate these standards.
And while the U.S. implementation of IEC 61511, ANSI/ISA 84, includes a "grandfather clause" for older systems, its insistence that operating companies ensure that safety systems are "designed, maintained, inspected, tested, and operating in a safe manner" leaves no room for less-than-rigorous safety system discipline.
Further, although the IEC SIS standards are not legal requirements per se, their growing acceptance as descriptors of industry best practices means that non-compliance may have very real liability implications in the event of an incident. And in some regions and industries, compliance already carries the force of law. On the other side of the ledger, demonstrated compliance can help operating companies to reduce insurance premiums.
Purposely non-prescriptive in nature, the IEC safety standards outline a holistic methodology for managing every stage of a safety systems' lifecycle—from risk analysis and design engineering through operations, management of change and decommissioning. Elements specifically relevant to safety systems performance assessment include adherence to accepted risk evaluation and mitigation methodologies such as process hazards analysis (PHA), hazards and operability (HAZOP) analysis, and layers of protection analysis (LOPA).
Much Work Remains for Industry Compliance
In a recent study of Control readers, we asked about familiarity with the IEC's 61511/ISA 84 safety instrumented systems standards and their company's compliance with their requirements. Roughly half of the predominantly North American audience indicated compliance of their systems with the standard or under the ISA 84 grandfather clause. Roughly a third of those respondents who indicated their systems were not yet compliant indicated their companies had established a roadmap and timeline, while another third indicated that compliance had made their to-do lists. A full quarter of respondents indicated no plans for compliance.
Revisit SIL Requirements
In light of the updated process performance parameters mentioned above, revisit the safety integrity level (SIL) requirements of your processes as well as the ability of safety instrumented functions (SIFs) implemented in preventive and protective layers to continue to adequately reduce risk. Further, ensure that the day-to-day operational discipline (maintenance tasks and proof tests) are being routinely executed at the proper intervals.
When evaluating safety risks, don't overlook the obsolescence risk presented by older safety systems that may be at or near the end of their supportable life, whether through the dwindling availability of spare parts—or of personnel qualified to maintain them. Indeed, today's integrated safety system technology can help reduce risk by unifying the plant's basic process control system (BPCS) and SIS engineering and visualization tools so that the plant's preventive and protective layers both perform more effectively.
The IEC's safety system standards strongly emphasize the importance of documentation at all lifecycle stages, notably the need to develop and maintain over time a clear and unambiguous functional safety requirements specification (SRS). And, much like the more familiar ISO 9000 series of quality standards, the ongoing integrity of safety system performance is to be assured at all lifecycle stages through the implementation of functional safety management systems (FSMS).
Competence and security are two additional aspects of SIS performance specifically addressed in the latest IEC standards and should be addressed in the course of any safety system performance assessment. This includes the documented competence of individuals and organizations involved with all aspects safety instrumented systems work as well as the inclusion of security threats in risk analysis methodologies.