AREA OF ANALYSIS
Pressure sensors to warn of an impending reactor rupture, temperature sensors to trigger an alarm that a reaction is out of control. In some process units, there are more safety-related sensors than those for process control.
Instrumentation certified for use in safety applications is thoroughly studied and characterized to get that rating. In most cases, its reliability is as high as any electro-mechanical device can be, but any device can fail given the right conditions or simply wear out.
That’s why periodic proof testing is so critical to ensure the different elements of the Safety instrumented systems are ready to act upon the appearance of the hazardous conditions in the process.