. A system that relies on two COTS components that have a required certification level SIL3 (probability of failure per hour of operation less than or equal to 10^-7). The developer purchases the two COTS with the required SIL3 certification level and assembles the system. What is the resultant certification level achieved by the system?

IEC 61508 standard provides the following information for the Safety Integrity Level (SIL).

SIL1 requires a probability of failure per hour of operation less than or equal to 10^-5

SIL2 requires a probability of failure per hour of operation less than or equal to 10^-6

SIL3 requires a probability of failure per hour of operation less than or equal to 10^-7

SIL4 requires a probability of failure per hour of operation less than or equal to 10^-8