Safety Integrity Level (SIL) Applied to the Belt Conveyor Design

In this paper, some of the hazards and operational risks related to belt conveyors were studied and it was proposed to install an interlock by an instrumented safety function, which, when detecting a high load on the conveyor, interrupts the dosage by closing a guillotine valve. The Hazop method was applied to identify hazards and the Lopa method to quantify the risks. In the function design, the safety lifecycle of the IEC 61511-1 standard was adopted, the method based on the reliability block diagrams, the simplified formulas of the VDI/VDE 2180-4 standard and spreadsheet electronic for calculations. To determine the probability of components failure, parameters such as λ_DU (dangerous undetected failure rates), voting architecture and tests interval. The reliability of the function was achieved, obtaining SIL1 with a risk reduction factor 40, probability of failure on demand of 2.48E-02 (0,0248) per year.