Abnormal Situation and Emergency Shutdown Response Procedure

Purpose. Describes how operators recognise, respond to and recover from abnormal process situations and safety system activations so that the plant is returned to a safe state and the event is recorded and learned from.

1.Scope

This procedure applies to any excursion beyond a safe operating limit, any safety system activation, any loss of a utility, any loss of containment and any alarm flood in the Kwinana plant. It must be read with the alarm response manual for each unit and the emergency response plan.

2.Recognising an abnormal situation

An abnormal situation exists when a process variable is outside its safe operating limit, when a critical alarm cannot be cleared within the response time in the alarm response manual, when more than ten alarms occur in ten minutes, when a utility is lost or when hazardous material is seen or smelt outside containment. The panel operator must declare the abnormal situation to the shift supervisor and the outside operators immediately.

3.Immediate response

The panel operator must take the actions in the alarm response manual for the alarm and must not exceed the response time before moving to the next level of response. The outside operator must move to the safe location upwind of the unit and must not enter the unit to investigate a suspected release without the protective equipment and the supervisor's instruction. The shift supervisor must decide whether to reduce rates, hold or shut down within the time in the manual.

• Identify the variable and the cause using the trend and the field report
• Take the manual actions in the alarm response manual
• Reduce feed or heat to bring the variable back within limits
• If limits cannot be restored in time, activate the emergency shutdown
• Confirm the shutdown has achieved the safe state on the control system and in the field

4.Emergency shutdown

The emergency shutdown system will isolate feed and heat, stop pumps, close the emergency block valves and route relief to the scrubber or flare. The panel operator must confirm each action on the shutdown status display and the outside operator must confirm valve positions in the field where it is safe to do so. The shift supervisor must notify the Production Superintendent and the Process Safety Manager and must record the time and the cause in the shift log.

5.Escalation to emergency response

If the situation involves a loss of containment, a fire, an injury or the potential for offsite effect, the shift supervisor must activate the emergency response plan, sound the site alarm and take the role of incident controller until relieved. Evacuation to muster points must be ordered where the plan requires.

6.Recovery and restart

The plant must not be restarted after an emergency shutdown until the cause is understood, the affected equipment has been inspected, the shutdown system has been reset and the Production Superintendent has authorised restart in the shift log. The restart must follow the unit start-up procedure from the pre-start-up checks.

7.Recording

Every abnormal situation, safety system activation and emergency shutdown must be recorded as a process safety event in the incident register before the end of the shift, with the trends saved and the sequence of events exported from the control system.