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The Importance of Functional Safety Assessment and its Application
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9. Summary
The process of performing FSAs demonstrates that a clear & independent strategy has been followed
during implementation of the required FS solutions.
FSAs provide timely identification and rectification of issues specific to the achievement of functional
safety, thereby reducing time overruns and has the potential to reduce re-work to project scope and
technical direction.
These assessments provide demonstrable evidence that an independent judgement has been made
on whether or not functional safety has been achieved and demonstrates that due diligence &
compliance to good practice e.g. IEC 61508 and IEC 61511 has been followed.
It improves supply chain relationships and supply chain cohesion as a result of the provision of FSA
reports to those other organisations implementing FSAs on the end-to-end safety instrumented
system.
FSAs establish an open and transparent process for supporting project personnel, in particular for
securing senior management involvement from both the supplier and client perspective.
In a nutshell, performing an FSA is a one-time small investment that provides significant benefit to
identify and reduce initial project execution and cost overruns due to potential functional safety issues
arising during the entire project lifecycle and the subsequent operational lifetime of the SIS.
10. References
[1] IEC 61508 edition 2 Functional safety of electrical/electronic/programmable electronic safety-
related systems International Standard 2010
[2] IEC 61511 edition 2 Functional safety - Safety instrumented systems for the process industry
sector International Standard 2016
[3] Out of control: Why control systems go wrong and how to prevent failure
HSE Books ISBN 0-7176-2192-8
[4] Managing competence for safety-related systems, IET/BCS/HSE, 2007 – Part 1: Key Guidance;
Part 2: Supplementary Material
[5] ISA-TR84.00.03-2012: Mechanical Integrity of Safety Instrumented Systems
[6] IEC 61800-5-2-2007: Adjustable Speed Electrical Power Drive Systems