What is the difference between SIL 1 2 and 3?

What is the difference between SIL 1 2 and 3?

What Is the Difference Between SIL 1, SIL 2, SIL 3, and SIL 4?

Defined criteria, Safety Integrity Levels (SIL) measure the degree of risk reduction a Safety Instrumented Function (SIF) offers inside a safety system. From lowest to highest, SIL 1 to SIL 4 reflect rising degrees of reliability and safety performance. The severity of possible risks, probability of occurrence, and the system’s capacity to identify and reduce failures all influence the choice of a certain SIL level.

  • SIL 1 SIL 1 applies to systems needing just fundamental safety functions where low-level threats exist. It’s appropriate for uses like food processing or building automation.
  • SIL 2 Used in chemical, pharmaceutical, and power generating industries, SIL 2 calls for more stringent testing and moderate risk reduction.
  • SIL 3 deals with high-risk settings, such nuclear power or oil & gas, where system failure might have grave effects.
  • SIL 4 The most strict SIL 4 is set aside for very vital uses like aerospace and defense, where failure is unacceptable.

Outlined in the table below, every level relates to a specified Risk Reduction Factor (RRF) and Probability of Failure on Demand (PFD).

SIL Level Comparison Table

SIL Level Risk Reduction Factor (RRF) PFD Range (Low Demand) Typical Applications
SIL 1 10 – 100 1.0E-1 to 1.0E-2 Food processing, building automation
SIL 2 100 – 1,000 1.0E-2 to 1.0E-3 Power plants, pharmaceuticals, chemical processing
SIL 3 1,000 – 10,000 1.0E-3 to 1.0E-4 Oil & gas, nuclear power, petrochemical plants
SIL 4 10,000 – 100,000 1.0E-4 to 1.0E-5 Aerospace, defense, critical nuclear systems