Accident models provide the basis for Investigating and analyzing accidents Preventing accidents Hazard analysis Design for safety Assessing risk(determining whether systems are suitable for use) Performance modeling and defining safety metrics Accident Models Basic Energy Model Assumes accidents are the result of an uncontrolled and undesired release of energy Use barriers or control energy flows to prevent them Barrier ENERGY OBJECT SOURCE Energy flc Variations Both(1) application of energy and(2 )interference in normal exchange of energy Energy transformation Vs energy deficiency Action systems(systems that produce energy)Vs nonaction systems(systems that constrain energy)c ✎✞✝✞✏✄✝✞✍✄☛✞✟☞✑✓✒✞✔ ￾✂✁✄✁✄☎✆✞✝✞✟✞✠✞✡☞☛✞✆✞✝✞✌✍ Accident models provide the basis for Investigating and analyzing accidents Preventing accidents Hazard analysis Design for safety Assessing risk (determining whether systems are suitable for use) Performance modeling and defining safety metrics c ✎✞✝✞✏✄✝✞✍✄☛✞✟☞✑✓✒✞✕ ￾✂✁✄✁✄☎✆✞✝✞✟✞✠✞✡☞☛✞✆✞✝✞✌✍ Basic Energy Model Assumes accidents are the result of an uncontrolled and undesired release of energy. Use barriers or control energy flows to prevent them. Barrier ENERGY Energy flow SOURCE OBJECT Variations: Both (1) application of energy and (2) interference in normal exchange of energy. Energy transformation vs. energy deficiency. Action systems (systems that produce energy) vs. nonaction systems (systems that constrain energy)