Safety Integrity Level (SIL) Verification Tool
IEC 61508 / 61511 compliance: calculate Average Probability of Failure on Demand (PFDavg) and verify SIL 1 through SIL 4 targets.
Core Formula
PFDavg = 1 - e^(-λDU × TI/2) ≈ λDU × TI / 2
Governing Standards
- IEC 61508 — Functional Safety of E/E/PE Systems
- IEC 61511 — Safety Instrumented Systems for Process Industry
Frequently Asked Questions
What are the SIL levels?
SIL 1: PFD 0.1–0.01, SIL 2: PFD 0.01–0.001, SIL 3: PFD 0.001–0.0001, SIL 4: PFD 0.0001–0.00001. Higher SIL = lower probability of failure on demand.