What is SiL4?

Answer 1

Safety Integrity Level (SIL) is defined as a relative level of risk-reduction provided by a safety function, or to specify a target level of risk reduction. In simple terms, SIL is a measurement of performance required for a Safety Instrumented Function (SIF).

The requirements for a given SIL are not consistent among all of the functional safety standards. In the European Functional Safety standards based on the IEC 61508 standard four SILs are defined, with SIL 4 being the most dependable and SIL 1 being the least. A SIL is determined based on a number of quantitative factors in combination with qualitative factors such as development process and safety life cycle management.

PFD (Probability of Failure on Demand) and RRF (Risk Reduction Factor) of low demand operation for different SILs as defined in IEC EN 61508 are as follows:SILPFDPFD (power)RRF10.1-0.0110−1 - 10−210-10020.01-0.00110−2 - 10−3100-100030.001-0.000110−3 - 10−41000-10,00040.0001-0.0000110−4 - 10−510,000-100,000

Answer 2

SiL4 stands for silicon tetrafluoride. It is a compound composed of silicon and fluorine atoms. SiF4 is a colorless, nonflammable gas used in the microelectronics industry for etching silicon.