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.

These works were carried out in the scope of the Cetim "Valve" professional

commission.