Understanding the How, Why, and What of a Safety ... - exida

1 Understanding the How, Why, and What of a Safety Integrity Level (SIL) Copyright LLC 2000-2016 Audio is provided via internet. Please enable your speaker (in all places) and mute your microphone. Understanding the How, Why, and What of a Safety Integrity Level (SIL) Audio is provided via internet. Please enable your speaker (in all places) and mute your microphone. There is a Q&A tab on the side of your screen. Please use this mechanism to type any questions you may have at any time. Questions will be read and answered. A recording of this session and a copy of the slides will be posted on the exida website and made available for you. Copyright LLC 2000-2016 Abstract The certification process is thorough and provides instant recognition of product reliability, Safety , and security that many end users are requesting certifications for products they buy to reduce liability and risk.

2 Manufacturers, if they haven t already, are staying ahead of the requests by certifying their products. During the certification process a manufacturer may have a requirement to certify their product to a certain Safety Integrity Level (SIL) rating. This webinar will cover: What happens in an exida certification? How to find a Safety integrity level How is SIL used? What this means for the manufacturer? What is SIL Capability? How to calculate SIL How to reach a certain rating Is there a way to improve a SIL rating? Copyright LLC 2000-2016 Loren Stewart, CFSP Loren Stewart graduated from Virginia Tech with a BSME. She has 8 years of professional experience originating in custom design and manufacturing.

3 She currently works for exida consulting as a Safety engineer, focusing on the mechanical aspects of their customers. Along with assessing the Safety of products and certifications, she continually researches and published reports on stiction and is creating a database for the 2H initiative according to IEC 61508. Copyright LLC 2000-2016 exida Worldwide Locations Copyright LLC 2000-2016 5 exida Industry Focus Copyright LLC 2000-2016 6 Automotive Nuclear Automation process Industry Main Product / Service Categories Consulting process Safety (IEC 61511, IEC 62061, ISO 26262) Alarm Management Control System Security (ISA S99) Product Certification Functional Safety (IEC 61508) Control System Cyber- Security Network Robustness (Achilles) Training process Safety Control System Security Onsite Offsite Security Development Alarm Management Engineering Tools exSILentia (PHAx, SIL Selection LOPAx SRS SIL Verification)

4 Safety Case FMEDA SILA larm SILStat CyberPHAx Reference Materials Databases Tutorials Textbooks Reference Books Market Studies Professional Certification CFSE CFSP Includes: -Automotive -CACE/CACS -Hardware -Machinery - process -Software Copyright LLC 2000-2016 7 Processes - Products - People exida has established schemes for functional Safety and cybersecurity certification of Systems, Products, Components, and Personnel. Functional Safety Certification involves a detailed analysis of both the engineering process and design margins resulting in random failure rate in all failure modes. Cybersecurity Certification involves a detailed analysis of the engineering process , cyber defense mechanisms, and network robustness.

5 exida Certification Copyright LLC 2000-2016 8 Reference Materials exida authored most industry references for automation Safety and reliability exida authored industry data handbook on equipment failure data exida authored the most comprehensive book on functional Safety in the market Copyright LLC 2000-2016 9 Engineering Tools Copyright LLC 2000-2016 10 exSILentia PHAx (HAZOP) LOPAx Layer of Protection database built-in SIL Selection Risk Matrix or Risk Graph Tolerable Frequency Basis Safety Requirements Specification SIL Verification Instrumentation failure database built-in Variables include reality test coverage, service Proof Test Generator Life Cycle Cost Analysis SILA larm ( alarm rationalization ) SILStat (Field Failure Data Collection and Analysis) Proof Test & Maintenance Activity scheduling process demand recording Failure recording CyberPHAx (Cyber Risk Assessment) Topics What happens in an exida certification?

6 How to find a Safety integrity level How is SIL used? What this means for the manufacturer? What is SIL Capability? How to calculate SIL How to reach a certain rating Is there a way to improve a SIL rating? Copyright LLC 2000-2016 WHAT HAPPENS IN AN exida CERTIFICATION? 12 Copyright LLC 2000-2016 1. Kickoff Meeting 2. Perform FMEDA Analysis on Product 3. Creation of the Proven-In-Use Analysis 4. process Analysis 5. Onsite audit 6. Certification Audit Certification process Copyright LLC 2000-2016 IEC 61508 Full Certification The end result of the certification process is a certificate listing the SIL level for which a product is qualified and the standards that were used for the certification.

7 However, we must understand that some products are certified with restrictions. The restrictions essentially indicate when a product does not meet some requirements of IEC 61508. The restrictions are listed in the Safety manual and must be followed if safe operation is required. 14 Copyright LLC 2000-2016 HOW TO FIND A Safety INTEGRITY LEVEL 15 Copyright LLC 2000-2016 16 1. The Systematic Capability Rating 2. The Architectural Constraints for the element 3. The PFDavg calculation for the product. The SIL level of a product is determined by three things: Copyright LLC 2000-2016 Compliance Requirements February 19, 2016 17 SIL Capability Probability of Failure Architectural Constraints Compliance Copyright LLC 2000-2016 THE SYSTEMATIC CAPABILITY 18 Copyright LLC 2000-2016 19 Systematic Capability is established by having your quality management system audited per IEC 61508.

8 If the QMS meets the requirements of 61508 a SIL Capability rating is issued. The rating achieved depends on the effectiveness of your QMS. The certificate is for the systematic capability of a product. The Systematic Capability Copyright LLC 2000-2016 THE ARCHITECTURAL CONSTRAINTS 20 Copyright LLC 2000-2016 21 Architectural constraints are established by following Route 1H or Route 2H. Route 1H involves calculating the Safe Failure Fraction for the element. A valve is typically one component of the final element of a Safety instrumented function (SIF). The Architectural Constraints Copyright LLC 2000-2016 Architectural Constraints from FMEDA Results 22 Route 1H - Safe Failure Fraction (SFF) according to of IEC 61508.

9 Safe Failures Safe + Dangerous Failures Route 2H - Assessment of the reliability data for the entire element according to of IEC 61508. Copyright LLC 2000-2016 Route 1H 23 TYPE A Safe Failure Fraction012< 60%SIL1 SIL2 SIL360% < 90%SIL2 SIL3 SIL490% < 99%SIL3 SIL4 SIL4> 99%SIL3 SIL4 SIL4 Hardware Fault ToleranceHardware Fault Tolerance = 1 (61508) The quantity of failures that can be tolerated while maintaining the Safety function. Copyright LLC 2000-2016 Route 2H Table 24 Hardware Fault Tolerance 0 1 2 SIL2 SIL3 SIL4 Type A Low Demand Applications Type B elements using Route 2H shall have a diagnostic coverage not less than 60%. Copyright LLC 2000-2016 THE PFDAVG CALCULATION 25 Copyright LLC 2000-2016 26 The PFDavg is based on the dangerous failure rate, system diagnostics, proof test coverage and test intervals.

10 Typically, a final element assembly will have a PFDavg the only meets SIL 1. However, there are things that can be done with the diagnostics and proof test that would improve the PFDavg to SIL 2. The PFDavg calculation Copyright LLC 2000-2016 HOW IS SIL USED? 27 Copyright LLC 2000-2016 Safety Integrity Level 28 Safety Integrity Level SIL 4 SIL 3 SIL 2 SIL 1 Used FOUR ways: 1. To establish risk reduction requirements 2. Probabilistic limits for hardware random failure 3. Architectural constraints 4. To establish systematic capability Copyright LLC 2000-2016 TO ESTABLISH RISK REDUCTION 29 Copyright LLC 2000-2016 Example of Risk Reduction 30 PHA Determines that a specific hazard can occur every 10 years causing a major release of toxic fumes into the atmosphere.