Reliability data safety instrumented systems SIS from the functional safety analysis example critical instalation

The dataset represents the results of an example of functional safety analysis systems is presented below. It is based on a control system, which consists of some basic components like sensors, programmable logic controllers and valves. It is a part of petrochemical critical installations. The communication between sensor logic controllers and actuators is implemented by wired devices vulnerable to cyber attacks. An example of the control and protection system with safety instrumented system (SIS) From the risk assessment the safety integrity level for given safety function overpressure protection pipeline was determined as SIL3. In industrial practice such level requires usually to be designed using a more sophisticated configuration. Safety function (overpressure protection) is implemented in distributed safety instrumented system. RBD model overpressure safety instrumented system SIS in the critical installation The required SIL for entire distributed E/E/PE or SIS system is determined in a process of risk analysis and evaluation. It has to be verified in the process of probabilistic modeling, taking into account its subsystems including networks. In situation of distributed control and/or protection systems operating in a network it is necessary to consider also potential failures within such network. RBD model SIS (E/E/PE) system including the industrial computer network The average probability of failure on demand PFDavg is calculated according to formula: where: PFDavgSYS - average probability of failure on demand for the SIS system, PFDavgS - for the sensor, PFDavgNet - average probability of failure on demand for the network, PFDavgPLC - for the PLC, PFDavgA - for the actuator.