1 provides a listing hierarchy of the independent layers of protection commonly found in the process industries. , evacuation, mutual aid) None* None*–Minor Minor–Major Major–Severe Severe– Catastrophic Catastrophic * Lack of these features may contribute to the magnitude of destruction which may occur. gency shutdown (ESD) features as the prime loss prevention measures. These features are immediately utilized at the time of the incident. Passive and active explosion and fire protection measures are applicable after the initiating event has occurred and an adverse effect to the operation has been realized.

Respond to the operational needs and desires: To provide effective process safety features, they should also be effective operational features. Providing safeguards that are counterproductive to safety may cause the exact opposite to occur, as operations may override or bypass the safeguard for ease of operational convenience. Protect the reputation and prestige of the company: Public perception of a company lowers if it is involved in a major incident that has considerable fatalities or does major harm to the environment.

All other emergencies are to be handled with emergency shutdown (ESD), blowdown, isolation, fire protection systems (active or passive) or exhaustion of the fuel sources by the incident Employee unrest: Opportunities for employee induced damages are minimized. , checklist, What-If, PHA, HAZOP, event tree, FMEA). The results of these analyses are fully understood and acknowledged by management. Where high risk events are identified as probable, quantifiable risk estimation and effects of mitigation measures should be undertaken and applied if productive.