For the pressure transmitter IS-20 with the ignition protection type ia (intrinsically safe) and ATEX approval, the safety-relevant data for SIL applications have been determined and summarized in the additional instructions “safety-related data” (PDF).

These include the Average Probability of Failure on Demand (PFDa), the Hardware Fault Tolerance (HFT) and the Safe Failure Fraction (SFF).

Process industry users need this information for a SIL evaluation of the complete application. For the requirements of the machine building industry, MTTFd (Mean Time To Dangerous Failure) values are provided in order to be able to determine the relevant Performance Level (PL).