Guidelines for application of SIL concepts to valve equipment

Final elements which make up the valve equipment may be integrated into safety systems. More and more customers require from industrial valve manufacturers (isolating valves, control valves, etc.) that their equipment present a given "SIL" (Safety Integrity Level) capacity and that they comply with the requirements of standard NF EN 61508. This standard is interesting on many levels. NF EN 61508, worldwide normative system, favours exchanges by standardising practices.
By making products and related services more common place, it contributes to reducing the cost of safety, improving availability and thus system productivity. This document summarises NF EN 61508 and explains the characteristics that valve equipment integrating a safety instrumented system must have. A determination and assessment approach of these characteristics is presented. It relies on case studies carried out with the trade on valve components.