exida has launched the web site www.silsafedata.com. SILSafe Data is a web site listing a number of product categories used in process control and the expected range of failure rates for process industry applications. The use of realistic and application appropriate failure rate data has a significant impact on the validity of SIL verification calculations. Unfortunately there is often conflicting or incomplete information readily available to perform the tasks needed for safe designs. The impact of poor information can lead to dangerous under-designed systems, expensive overdesigns or even the need to re-design the safety integrated system.
Determining if data is suitable for use is a critical first step. The SILSafeData.com website is a listing of upper and lower bounds for various devices commonly used in safety instrumented functions. These bounds were derived from statistical analysis of FMEDA results which represent design variations and application variations in combination with extensive comparisons with realistic field failure data. exida calls this technique “Predictive Analytics.”
The upper bound and lower bound dangerous failure rate data in SILSafeData is presented to perform quick comparisons with any piece of data. If the dangerous failure rate provided is not within the limits, further analysis and justification is warranted before using the provided data.
For more device information or individual FMEDA results, look to the Safety Equipment Reliability Handbook (SERH). The SERH provides a collection of failure rate data that is applicable for use in Safety Instrumented System (SIS) conceptual design verification in the process industry. The Safety Equipment Reliability Handbook remains the ultimate reference source for any safety engineer involved in Conceptual Design and Safety Integrity Level verification.