End user experiences with applying IEC 61511 to legacy plants
Author : Jeff Wood
17 November 2009
Following his successful paper at the HazardEx 2009 event Jeff Wood, instrument engineer, from Ineos Chlor Vinyls will return to deliver an insight into end user experiences with applying IEC 61511 to legacy plants
At last year's conference Jeff presented a paper on Ineos Chlor's experiences, as an end user, with engineering the safety instrumented systems for a major new plant with major hazard potential in accordance with the requirements of IEC 61511. That plant was built on the Runcorn, UK site of Ineos ChlorVinyls Ltd where it is now operated alongside a number of legacy plants that date back to the 1960s and 70s. This paper will discuss our experiences with assessing the safety instrumented systems on these existing plants in order to demonstrate compliance with current good practise.
The Runcorn Site was formally owned by ICI who, partly as a result of incidents that occurred in the 1960's, contributed to the development of modern hazard study and instrument protective system design techniques. This heritage meant that, when IEC 61508 was published in 1998 and IEC 61511 followed in 2003, we already had many of the recommended systems and procedures in place although not necessarily in quite the format required. Whilst we fairly quickly adopted the new standards for use on new projects there was no immediate drive to apply them retrospectively to existing assets. However, as time went on, as a top tier COMAH site, it became increasingly difficult to justify sticking to using the old in-house systems for existing plants and it became necessary to demonstrate compliance with current good practise. This resulted in a major activity to review the integrity requirements of our existing safety instrumented systems along with their design, proof testing and maintenance standards. Details of this process, the problems encountered and involvement of our regulators will be presented.
This is a paper being presented at the HazardEx 2010 conference
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