Abstract IEC 61511 requires periodic proof testing of SIFs to demonstrate the correct operation of the loop elements based on Safety Instrumented Function (SIF) design criteria to maintain Safety Integrity Level (SIL) ratings. Proof test serves three primary purposes within the safety lifecycle: To catch and overcome the failures in the system. To validate SIF integrity and reliability To record and classify failures in a consistent manner to support future analysis. Challenges with implementing a new or modified approach to testing of Safety Instrumented System (SIS) instruments include issues such as education of participants, integrating the new proof testing procedures with the current maintenance plans and schedule, and documenting failures identified outside of testing. It is critical to create an implementation plan that deals with these challenges ahead of pushing SIS proof testing to facilities. This paper will: Identify methods to achieve maximum % proof test coverage Proper planning and scheduling Review guiding principles upon which proof tests be developed.