Actuator Focused Hazard Analysis

In the early stages of a design process, a detailed hazard analysis should be performed, particularly for safety critical systems. In this paper an actuator based hazard analysis method is presented. Since it is the actuators that affect the systems environment, this actuator based approach is the logical approach for an early hazard analysis when only limited information of the system implementation is available. This approach is also unique since all identified failures are distributed on four different severities. A criticality ranking is assigned to each failure as a combination of the severities and their distribution. This ranking is also used to give an indication of the preferred fail states. For the hazards resulting in a high criticality that needs to be handled, the method supports a solvability analysis between different design solutions. This solvability analysis rewards design concepts that handles hazards with high criticality numbers