Safety instrumented systems provide a layer of protection beyond the control system to safely shutdown the process during abnormal situations. A safety instrumented function (SIF) or “safety loop” includes the sensing device, logic solver and final control element to perform safety function upon demand. Flow measurement devices are often the sensing devices in these SIFs. […]
Safety instrumented systems (SIS) include the sensor(s), final control element(s) and logic solver(s) for each of the safety instrumented functions (SIFs) in the SIS. To verify the SIFs are performing the amount of risk reduction intended for their application, they must be periodically proof tested. PCN Europe magazine interviewed Emerson’s Teddy Tzegazeab on how proof […]
Backing up your computer or server is a waste of time if restoring the backup fails when you need it. Good practice is to test these backups on separate test systems periodically to make sure they restore properly. Similarly, safety instrumented systems (SISs) need to assure that each safety instrumented function (SIF)/safety loop does what […]
Valves are critical components inside of safety instrumented functions (SIFs) since they do the work of touching the process flows to bring the plant to a safe state in the event of a safety demand. In a Valve magazine article, How Valve Selection Can Impact SIS in Refining Applications, Emerson’s Janine McCormick describes the important […]
For safety instrumented functions (SIFs), proof testing is the process of identifying undetected dangerous failures in the sensor, final control element and logic solver which comprise the SIF. Dangerous failures are those that could put the safety instrumented system (SIS) in a hazardous or fail-to-function state. If undetected, in the case of level measurements, this […]
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