August 2024 — Imagine discovering a critical flaw in your safety system design before your plant goes operational. This scenario, while nerve-wracking, underscores the importance of early intervention in the design phase. When developing a Safety Instrumented System (SIS), it’s crucial to ensure that the hardware and software meet the practical needs identified from the initial hazard and risk assessment. That’s the purpose of a functional safety assessment (FSA).
FSAs, as defined by IEC 61511, provide a five-stage, evidence-based investigation to judge the functional safety achieved by one or more SIS and/or other protection layers.
Stages 1 through 3 of the FSA encompass the SIS from its original concept through design, construction, and commissioning. Stage 1 specifically takes place after the hazard and risk assessments have been completed and before detailed design work begins, which can help with the early identification of design flaws and safety issues.
Here’s what to expect in the Stage 1 FSA process, along with recommendations for a successful outcome.
What Are the Goals of a Stage 1 FSA?
A well-executed FSA reduces the likelihood of safety incidents. For FSA Stage 1, the primary goal is to verify that the safety requirements specification (SRS) accurately reflects the needs identified during the hazard and risk assessments. Does what’s on paper reflect the scenario in which the SIS must operate in the real world? Will the SIS actually mitigate the risks identified in the hazard and risk assessment?
By ensuring thorough verification of the SRS at this early stage, Stage 1 FSAs help prevent costly modifications and delays later in the project lifecycle. Proper planning leads to smoother project execution, reducing downtime, and increasing overall efficiency.
The deliverable for a Stage 1 FSA includes a comprehensive report that presents findings, recommendations, and general observations. It is a good idea to loop in stakeholders to review this deliverable together to align on opportunities to course-correct and next steps. Key personnel include process engineers, control engineers, operations supervisors, and site leadership.
What is the Anticipated Time, Cost, and ROI of a Stage 1 FSA?
The effort for executing an FSA is minimal relative to the overall project. The initial cost of performing a Stage 1 FSA includes expenses related to document reviews, stakeholder interviews, and detailed analyses. The expense is minimal compared to the total project cost. The duration of a Stage 1 FSA can vary based on the project's size and complexity, typically involving several days of document reviews and interviews with key personnel.
Failing to conduct a thorough Stage 1 FSA can lead to incomplete or incorrect safety requirements. This oversight can result in costly modifications, delays, and potentially catastrophic failures once the system is operational. These issues often incur far higher costs than the initial FSA investment. A Stage 1 FSA can help surface the following issues:
● Incomplete risk assessments
● Failure to capture safety requirements
● Insufficient detail in the preliminary assessments.
● Inadequate stakeholder engagement
Conducting a Stage 1 FSA allows for early identification of design flaws and safety issues, which are less expensive to address in the design phase than during or after construction.
What is The FSA Stage 1 Process?
The FSA Stage 1 process typically consists of the following steps:
● Hazard and risk assessment verification
● Verification of safety requirements specification
● Operational readiness
Table: Process Steps for FSA Stage 1
Process Step | Objectives |
Hazard and Risk Assessment V | ● Review of Hazard Analysis: Ensure that all potential hazards have been identified and assessed. ● Risk Assessment Validation: Confirm that the risk assessments accurately reflect the potential consequences and likelihood of identified hazards. |
Verification of Safety Requirements Specification | ● Document Review: Verify that the SRS accurately captures all safety requirements derived from the hazard and risk assessments. ● Design Verification: Ensure that the proposed SIS design addresses all identified safety requirements and mitigates the associated risks. ● Cross-Functional Collaboration: Engage with multiple stakeholders to verify the SRS and ensure it reflects the input and expertise of all relevant parties. |
Operational Readiness
| ● Stakeholder Engagement: Confirm that all relevant stakeholders, including process engineers, control engineers, and operations personnel, are involved in the development and review of the SRS. |
What Are the Renewable Energy Implications
As renewable energy sources reach maturity in the market, the nature of hazards and associated risks change with new unknowns and limited data.
Consider the unique explosion and flammability risks of hydrogen, which is relatively new to the market. The hazard and risk assessments for hydrogen facilities must account for these unique dangers. Similarly, large-scale battery storage systems, essential for renewable energy, can suffer from thermal runaway leading to fires and explosions. Wind and solar farms present risks such as electrical hazards, mechanical failures, and environmental impacts. It is critical that the team conducting the FSA understands the unique hazards.
Conclusion
Stage 1 FSAs help prevent hazardous events and protect both personnel and assets. Engaging the team actively and addressing potential issues proactively can significantly enhance the effectiveness of Stage 1 FSAs, ensuring the safety and reliability of industrial operations.
If you have any questions about your scenario, aeSolutions is here to provide support. Our team of industry experts are available to help navigate even the most unique challenges.
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