(8a) Resilience Against External Events Using Vulnerability Assessment and QRA

Resilience – Vulnerability Assessment and Quantitative Risk Assessment for
Resistance and/or Recovery from Extreme Weather
Events (Hurricanes, Earthquakes, Floods and Tornadoes)
and Earthquakes

Peter A. McKnight, Paul Amico and Bijan Najafi

JENSEN HUGHES

Process Safety Management Team

and

Power Services Group

Advancing the
Science of Safety

Abstract

Greater frequency and severity
of extreme weather and geologic events has increased the likelihood of emergency
shutdowns and extended outages at processing plants in areas affected.  These events have brought into question the
resilience of Chemical Processing Plants and Oil and Gas Refinery operations
against extreme weather and earthquakes. 
Vulnerability Analyses review a Plant’s potential to be affected, by
considering supply chain and infrastructure effects that would impact
continuity of operations as well as the availability and ability of operators
and plant personnel to safely operate the facility.  They also consider the resiliency to
restarting operations safely and expeditiously following emergency shutdowns.  This paper presents a method using
qualitative and quantitative assessment techniques within a Process Safety
Management Framework.  It includes a thorough
review of the plant processes that would benefit from hardening or protection of
equipment and systems to prevent storm or natural disaster damage, followed by resilient
measures such as capital spares of key operating components to expedite re-establishing
processing capability.  Resilience
also allows consideration of the ability of the Plant to withstand other extraordinary
events, safety and security of Plant equipment and personnel, and continuity of
operations.

The authors will discuss the practical
application of hazard/vulnerability analyses and Quantitative Risk Assessment
(QRA) to focus investment on the most vulnerable units of the facility to apply
Hard and/or Soft Resilience Measures for Industrial Plants susceptible to
extreme conditions:

Hard Resilience:  Focus on resistance. ‘Fail-safe’ –
constructing units of operation and equipment to withstand sudden impact with
the assumption that strength or protective enclosures will make them safer and
less prone to failure. Looks to strengthen individual units, process trains and
selected assets.

Soft Resilience:
Focus on absorption. ‘Safe-fail’ – constructing and preparing process trains
and units of operation that recover quickly from shutdowns and outages, assuming that infrastructure elements (power, water, supply
chains) will fail and preparing for their inevitable failures. Reducing the
impact of operational disruptions by taking the view that repairs and
replacement of damaged units is part of a systematic continuity of operations
plan.

Provide Case Studies where application
of QRA and PSM Programs have benefitted Energy Infrastructure Clients and related
Facilities through increased Reliability, Availability and Maintainability (RAM)
and improved continuity of operations applying both Hard and Soft Resilience
Measures.

Keywords:
 Process Safety Management, PSM, Quantitative
Risk Assessment (QRA), Resilience, Expedited Re-Start Measures, Corrective
Measures, Preventive Maintenance and Redundancy, Long-Lead Items, Hardened
Protective Measures, Modular Process Unit Replacement Approach – Post-Incident,
hard resilience, soft resilience, vulnerability assessment,