Re: [sc] 51028 and 61508
Nicholas Lusty wrote:
> Both give identical probabilistic definitions of SIL-3 and SIL4.
There seems to be a complete disagreement between subscribers to this
list about whether or not SILs are defined probabilistically. In the
past weeks, we have seen several unequivocal statements that 61508 does
NOT define SILs probabilistically. How can something so fundamental to
safety be allowed to remain unclear?
[If anyone is tempted to say that 61508 defines system-level SILs
probabilistically whilst stating that probabilities do not apply to
software, then I challenge them to explain how 61508 suggests that one
can provide adequate evidence for a system-level probability of failure
if the system contains software].
Received on Mon 30 Nov 2009 - 14:22:04 GMT