A fault propagation method used to analyze failure rate or probability for safety instrumented functions. A diagram is constructed to represent the system under consideration including the logical relationships between its components. In Markov analysis there are a group of circles, each of which represents a system state. The different states are connected with transitions, which are shown as arrows and indicate paths to move from one state to another. The transitions are quantified using either failure rates when the transition is from an OK state to a failed state or repair rates when the transition is from a failed state back to an OK state. As with other models, there are several solution methods to obtain results. For safety instrumented system applications, the method using steady state equations is not appropriate. Numeric discrete time solutions are excellent.