MAR Consulting supported performing and documenting a Probability of Failure on Demand (PFD) calculation. Due to the addition of new wells to the offshore producing platform in the Norwegian Continental Shelf (NCS), an hazard analysis identified a potential overpressure scenario. The production header has mechanical protection (relief valves) and a Safety Instrumented Function as a redundant barrier. Hence, MAR Consulting calculated the average PFD for this low demand Safety Instrumented Function (SIF). The PFD, when compared to the required risk reduction for this scenario, is acceptable for a number of new wells.