With the background of functional safety established, it's easier to layout what functional safety is versus generic safety. Safety is freedom from unacceptable risk of physical injury or damage to the health of people or to the environment. Functional safety is the portion of safety that depends on the correct function of the process or equipment in response to its inputs. In other words, functional safety is the safety pertaining to the operation of equipment or systems. The goal of functional safety is to reduce the level of risk in a piece of equipment or system. Risk, in the eyes of functional safety, is seen as the severity of the failure of the equipment or process multiplied by the probability that it will occur given the components of the system.