SIL/LOPA ASSESSMENT

Assessment of safety functions – safety integrity level (SIL) assessment, also known as instrument protective function (IPF) classification provides a measure of the consequences of failure for the system or for the equipment’s safety, any implications for the surrounding environment, and the potential financial implications for the operating company such as loss of production, replacement of equipment, etc. There are 4 levels of SIL assessment, each corresponding to a range of target likelihoods of failure of a safety function. SIL 1 corresponds to the highest probability of failure to demand (PFD), and SIL 4 the lowest PFD. A safety documentations review is carried out initially to identify relevant information required for the assessment.