Introduction to IEC 61508:2010
IEC 61508:2010, “Functional safety of electrical/electronic/programmable electronic safety-related systems,” is a series of standards issued by IEC. IEC 61508:2010 defines a generic approach for all safety lifecycle activities regarding systems comprised of electrical and/or electronic and/or programmable electronic (E/E/PE) elements that are used to implement safety functions. IEC 61508:2010 is applicable to all industries. Several product and application sector international standards based on the IEC 61508 series have been developed, but the general framework set out by IEC 61508:2010 is applied as is whenever a more specific standard is not available.
IEC 61508:2010 considers all software safety lifecycle phases (e.g., initial concept, design, implementation, operation, maintenance decommissioning) of E/E/PE systems that are used to perform safety functions. In particular, it provides a method for the development of the safety requirements specification necessary to achieve the required functional safety for E/E/PE safety-related systems. This is based on a risk-based approach based on the notion of Safety Integrity Level (SIL) for specifying the target level of safety integrity for the safety functions to be implemented by E/E/PE safety-related systems.
There are four SILs: 1, 2, 3 and 4, with 1 being the lowest safety integrity level and 4 being the highest. Each SIL correspond to a different range for the average probability of a dangerous failure; the ranges are different depending on the mode of operation of the system, (low demand, high demand or continuous). On the low demand mode of operation, SIL 4 corresponds to an average probability of a dangerous failure on demand of the safety function in the range [10−5 , 10−4 ]. On the high demand and continuous modes of operation, SIL 4 corresponds to an average probability of a dangerous failure per hour of operation of the safety function in the range [10−9 , 10−8 ].
Role of ECLAIR in Ensuring Compliance with IEC 61508:2010
The ECLAIR Software Verification Platform can be used to comply with several of the techniques and measures required by IEC 61508:2010 Part 3 “Software Requirements”. In addition, the ECLAIR Fusa Pack greatly simplifies obtaining all the confidence-building evidence that is required to make a solid argument justifying the use of ECLAIR in safety-related projects.