What is a SIL rated system?

SIL is a relative level of risk reduction provided by a safety function. SIL ratings correlate to the frequency and severity of hazards. They determine the performance required to maintain and achieve safety — and the probability of failure.

What is SIL rated equipment?

SIL certification is a tool to measure the amount of risk reduction provided by a Safety Instrumented Function. It assesses the tolerable/acceptable failure rate of an individual device. This is important when installing or retrofitting an instrument into a SIS.

How is SIL rating determined?

To determine a SIF’s SIL level, the SIF’s overall PFD must be calculated. This SIL calculation basically combines the Failure Rate data for each of the individual SIF components (i.e. the sensors, logic solvers and control elements) and accounts for test frequency, redundancy, voting arrangements, etc.

How are SIL measured?

The SIL value for the safety system is determined by comparing the required probability of failure to the international standards of functional safety, defined in IEC 61508 and IEC 61511.

Which SIL is the best?

The Meaning of Safety Integrity Level (SIL) 99,999 in 100,000). There are four discrete integrity levels associated with SIL: SIL 1, SIL 2, SIL 3, and SIL 4. The higher the SIL level, the higher the associated safety level, and the lower probability that a system will fail to perform properly.

What is the highest level of SIL?

SIL 4
The Meaning of Safety Integrity Level (SIL) 99,999 in 100,000). There are four discrete integrity levels associated with SIL: SIL 1, SIL 2, SIL 3, and SIL 4. The higher the SIL level, the higher the associated safety level, and the lower probability that a system will fail to perform properly.

What is a SIL 2 rating?

SIL2 – Low statistical risk of failure that you do not know about in the product.

Is SIL 2 better than SIL3?

The difference between a transmitter certified for use in SIL3 applications and a SIL2 certified unit is that the SIL3 unit will have satisfied more onerous requirements with respect to its design, in particular reliability and failure modes.