Posts Tagged ‘FMEDA’

Partial Stroke Test for Final Elements—Diagnostic Coverage Factors

Posted in Final Control Element, Safety on Thursday, December 13th, 2018. No comments yet
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Author: Riyaz Ali Partial stroke test is one of the viable means to check mechanical integrity of Final Element of Safety Instrumented Function (SIF) loop. Generally, end users struggle on question of credit of PST for improvement in SIL (Safety Integrity Level). IEC 61508 and IEC 61511 define diagnostic coverage factors (DCF), but do not […]

Redundancy and Diagnostics in Safety Instrumented System Sensors

Posted in Safety on Wednesday, December 12th, 2012. 2 comments so far
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This past Emerson Exchange conference has a treasure trove of presentations as it does every year. I’ve gone into the trove and mined this presentation, Measurement Diagnostics in Safety Instrumented Systems, by Emerson’s Mark Menezes. The presentation is based on an article from several years ago, Measurement Best Practices for Safety Instrumented Systems by Mark […]

Detecting Loop Electrical Integrity Issues

Posted in Pressure, Technologies on Thursday, March 8th, 2012. No comments yet
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Advanced diagnostics are improving our lives in many ways from healthcare to transportation. And in our world of process automation, they are fundamentally changing the way we operate and manage our plants. In an earlier post, A High-Speed, Statistical View for Better Decision Making, I shared how statistical process monitoring (SPM) techniques can help spot […]

Ways to Build Process Safety Competency

Posted in Final Control Element, Safety on Thursday, March 31st, 2011. No comments yet
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An important topic we touched on in an earlier post was process safety competency. The post, Developing Safety Competency, noted the importance of people involved in the safety lifecycle who must be competent in the areas of this lifecycle in which they interact. Training plays a large role in developing this competency. For suppliers of […]

Failure Modes of Positioners in Safety Applications

Posted in Final Control Element, Safety on Wednesday, October 6th, 2010. No comments yet
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A few weeks ago, I highlighted a thread from the ISA Safety email list on partial stroke testing using control valve positioners. A few weeks later, this thread is still going strong. Emerson’s Riyaz Ali sent me some of the recent exchanges. A concern was expressed about the failure modes in an I/P [current-to-pneumatic] converter […]