Optimizing Proof Test Interval: A Case of Study at Calumet Specialty

It does not matter how much effort is compromised towards calculating a safety instrumented system (SIS) performance if it is not validated, implemented, audited, assessed and maintained according to the assumptions made during the early phases of the SIS project. Yet operating companies face the day to day burden of keeping their costs while still keeping their personnel and assets safety.

This paper discuss the practical approach of proof testing such safety systems and considerations regarding proof test coverage compared to the actual site maintenance capability; useful life of devices pertaining to critical applications; and corresponding proof test procedures to address the parameters adopted in the SIL verification calculations.

Calumet Specialty’s case study presents the opportunities observed while reviewing their safety instrumented functions, which resulted in a planned and gradual optimization in their periodic preventive maintenance.

Keywords

Proof test interval, Safety Instrumented System, Prior use, PSM & FSM