Event & target likelihood | Cause & likelihood | IPL (Integrated Protection Layers) and its PFD (Process Failure on Demand) | Mitigated likelihood | |||
Pressure release valve between scrub tower fails to open causing product loss
1E−6 | Pressure Release vale malfunctions and fails to open
1E−2 | Human action | Alarms | SIS (PLC) | Design | 2.6E−9 |
Human response to the alarm and manually close the valve before the pressure release valve
1E−1 | A noticeable Alarm that would start if the flow rate kept low for a few minutes
2.6E−1 | Logic in PLC once a a change in the Gas flow rate detected after the scrubber with a reasonable amount, a bypass for the scrubbing would occur and flow redirected to flare
1E−3 | A manual valve would be added before the pressure release valve
1E−2 |