Safety Integrity Level (SIL) Calculator

Evaluate combined Probability of Failure on Demand (PFDavg) for Safety Instrumented Functions (SIF) based on IEC 61508 low demand criteria.

Purpose of this Tool: Validate that loops satisfy plant safety integrity specifications per IEC 61511 design safety criteria.

• Combined Series PFDavg:PFD_{avg\ total} = PFD_{sensor} + PFD_{solver} + PFD_{final\ element}

• Risk Reduction Factor (RRF):RRF = \frac{1}{PFD_{avg\ total}}

Sensor Subsystem PFDavg

0.00010.05

Logic Solver Subsystem PFDavg

0.00010.01

Final Control Element PFDavg

0.00050.1

SIL Target Compliance

Combined PFDavg Total0.01050

Low Demand PFD

Target SIL Level CompliedSIL 1

RRF Target: 10 to 100

Risk Reduction Factor (RRF)95

RRF Index

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