Lifecycle of the ESD valve – Install-and-forget device?[R] Author: Ville Kähkönen Director Metso Flow Control Company: Metso Flow Control Download Abstract • A SIF protects against a single hazard, but a Safety Instrumented System (SIS) implements one of more SIFs• SIS takes the process to a safe state in case of emergency• SIS consist of three elements: sensor, logic solver, final element