The purpose of Decommissioning in the Functional Safety Lifecycle is to ensure that prior to taking a SIF out of service, a proper review is conducted so that there is no impact on the functional safety of other SIFs during decommissioning.
Decommissioning of a Safety Instrumented Function should be properly planned, reviewed and approved prior to making the change. The safety integrity of the SIS must be maintained despite any changes made.
An analysis must be carried to determine the impact on functional safety and is usually termed the Impact Assessment.
ProSalus has assisted clients in the developments of management of change procedures, impact assessments and post modification Functional Safety Assessment.