When we talk about safety certifications in the railway world, it is common to refer to SIL2 certification, but what is this certification and why is it so important?
SIL is an acronym for Safety Integrity Level. This acronym is widely used in the railway sector and refers to the probability that a system successfully fulfils the required safety functions. The aim is therefore to ensure that there are no failures that pose unacceptable risks. These failures to be avoided may include:
- Systematic: Those resulting from design, manufacturing or maintenance errors are categorised in this group
- Random: This group includes those that occur in mechanical and electronic equipment, not caused by man’s hand, but due to wear and tear and ageing of the device.
Security levels
Now that we have defined what safety integrity is, and against which failures it is measured, we must clarify that this concept is calculated taking into account a number of concepts, such as the probability of failure of a safety function with low demand or continuous use, the failure rate, the mean time between two consecutive failures, or the ability of the system to continue functioning in the event of failures.
Once these measurements have been taken, the safety level achieved is indicated numerically after the acronym SIL. This results in SIL1 certification, SIL2 certification, SIL3 and SIL4, the latter being the highest safety level, in which the occurrence of systemic and random failures is highly improbable.
Determining the level of integrity required by each system is based on a risk analysis in which the consequences and probability of a system failure are evaluated. At EEE we design SIL certified systems, aligned with the most demanding quality and efficiency standards required in railway systems.
