[:en][vc_row][vc_column][us_single_image image=”16847″ size=”full”][vc_row_inner][vc_column_inner][vc_column_text]Safety Instrumented Function Verification: The Three Barriers

The three constraints (systematic capability constraint, architectural constraint, and probabilistic performance metric constraint) that are implied by requirements per international safety standards IEC 61511 [1] and IEC 61508 [2] to determine the safety integrity level (SIL) of a safety instrumented function (SIF) are described and discussed. Examples of their applications are presented. For low demand mode SIF operation, the importance of including numerous key variables in the computation of average probability of failure on demand (PFDavg) is noted.

Download the White Paper[/vc_column_text][/vc_column_inner][/vc_row_inner][vc_row_inner][vc_column_inner][us_separator type=”invisible” size=”small”][vc_column_text][/vc_column_text][/vc_column_inner][/vc_row_inner][/vc_column][/vc_row][:zh][vc_row][vc_column][us_single_image image=”1743″ size=”full”][vc_row_inner][vc_column_inner][vc_column_text]The discipline of Reliability Engineering depends upon a key metric, failure rate. In the past, it was practical to perform a “life test” (or an “accelerated life test”) where devices were operated in a defined set of conditions and failure times were recorded. This failure time data was analyzed to obtain the failure rate of the device [1, 2]. This technique was far more practical with the technologies of 1950s and 1960s. Vacuum tubes failed so frequently that “tube testers” (Figure 1, provided assuming some readers have never seen a vacuum tube) were commonly seen in retail stores where new vacuum tubes were sold.

Today’s electronic technology is far more reliable such that the life test approach is rarely seen except perhaps for mechanical devices.[/vc_column_text][/vc_column_inner][/vc_row_inner][vc_row_inner][vc_column_inner][us_separator type=”invisible” size=”small”][vc_column_text][/vc_column_text][/vc_column_inner][/vc_row_inner][/vc_column][/vc_row] [:]