We may all say accidents happen. However, their occurrence may not only take human lives, destroy millions of dollars in property and lost business, they may also cost us our jobs(职业,职位) and reputations(名誉,名声).
Accidents don’t just happen; they are a result of a long process, with many steps. Many times all of these steps have to be completed before an accident can occur. If the engineer can prevent one or more of these accident steps from occurring, then he can either prevent the mishap or at least mitigate its effects.
An accident is an unplanned process of events that leads to undesired injury, loss of life, damage to the system or the environment. This means that death in war is no accident, but a jeep crashing on the way to battle is. Part of system safety strategy is to intervene at various points along that accident timeline.
Preliminary events can be anything that influences the initiating event. Preliminary events set the stage for a hazardous condition. The initiating event, sometimes called the trigger event, is the actual mechanism or condition that causes the accident to occur.