Accident Investigations and Case Histories

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Accident Investigations and Case Histories

• University of Missouri - Rolla
• ChE 258
• Chemical Process Safety

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Overview

• Introduction
• Layered Investigations
• Investigation summary
• Case Histories
• Diagnosis (forensic engineering)
• Group Presentations
• Example

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Introduction

• Accident investigations and case studies provide
  opportunities to learn how to prevent similar
  accidents from occurring.
• Learn from someone elses mistakes (dont need to
  put your hand in a fire to know it will be
  burnt).
• Most companies willingly share this information
  to improve safety across the industry.

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• Center for Chemical Process Safety (CCPS)
• UMR Connection
• Dr. Randy Freeman, UMR alumnus and Academy member
  (1997), has held several leadership positions in
  CCPS
• Dr. Joseph Louvar (author of textbook), UMR
  alumnus and Academy Member (2000), has served in
  the associated organization, SACHE which is the
  CCPS undergraduate Education Committee

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• Accident Investigations.
• Most modern accident investigations use the
  layered concept.
• First layer -Immediate technical recommendations
• Second layer - Recommendations to avoid hazard
• Third layer - Recommendation to improve
  management system
• The layered approach helps to uncover the
  underlying causes

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Layered Accident Investigations

• WHAT is the purpose of the operation involved in
  the accident?
• WHAT equipment failed?
• WHAT material leaked (exploded, decomposed, etc)?
• WHICH people could have performed better?

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• Questions for Layered Accident Investigations1
• WHAT is the purpose of the operation involved in
  the accident?
• WHY do we do this?
• WHAT could we do instead?
• HOW else could we do it?
• WHEN else could we do it?
• WHERE else could we do it?
• 1 from Trevor Kletz, Process Plants A Handbook
  for Inherently Safer Design (Philadelphia Taylor
  Francis, 1998), p 175

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• Questions for Layered Accident Investigations1
• WHAT equipment failed?
• HOW can we prevent failure or make it less
  likely?
• HOW can we detect failure or approaching failure?
• HOW can we control failure (i.e., minimize
  consequences)?
• WHAT does this equipment do?
• WHAT other equipment could we use instead?
• WHAT could we do instead?
• 1 from Trevor Kletz, Process Plants A Handbook
  for Inherently Safer Design (Philadelphia Taylor
  Francis, 1998), p 175

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• Questions for Layered Accident Investigations1
• WHAT material leaked (exploded, decomposed, etc)?
• HOW can we prevent a leak (explosion,
  decomposition, etc.)?
• HOW can we detect a leak or approaching leak
  (etc.)?
• WHAT does this material do?
• WHAT material could we use instead?
• WHAT safer form could we use the original
  material in?
• WHAT could we do instead?
• 1 from Trevor Kletz, Process Plants A Handbook
  for Inherently Safer Design (Philadelphia Taylor
  Francis, 1998), p 175

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• Questions for Layered Accident Investigations1
• WHICH people could have performed better?
• Consider people who might supervise, train,
  inspect, check, or design better than they did.
  Also consider people who might construct, operate
  and maintain.
• WHAT could they have done better?
• HOW can we help them to perform better? (Consider
  training, instructions, inspections, audits,
  etc., as well as changes to design)
• 1 from Trevor Kletz, Process Plants A Handbook
  for Inherently Safer Design (Philadelphia Taylor
  Francis, 1998), p 175

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Example 12-1 Pool Accident

• A drowning accident occurred during an open swim
  period. Approximately 100 children, ranging
  between 5 and 16 years old, were in and around a
  pool. An older child unknowingly pushed a 5 year
  old into the deep water. The pool is relatively
  crowded, and the 5 year old slipped under the
  water without being noticed by others, including
  the lifeguard.

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Example 12-1 Pool Accident - Layered
Investigation

• First layer
• Immediate technical recommendations
• 1) Paint pool depths at the pool edges.
• 2) Add more lifeguards.
• 3) Reduce the number of swimmers.

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Example 12-1 Pool Accident - Layered
Investigation

• Second layer
• Avoiding the hazard
• 1) Prohibit horseplay.
• 2) Zone pool to keep smaller children at shallow
  end of pool.
• 3) Add swimming lessons for all age groups.
• 4) Give all new swimmers (especially young
  children) a pool orientation.
• 5) Add a roving lifeguard to monitor and control
  pool behavior.

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Example 12-1 Pool Accident - Layered
Investigation

• Third Layer
• Improving the management system
• 1) Train lifeguards to alert supervision of
  observed potential problems.
• 2) Assign supervisor to make formal (documented)
  audits on a regular basis.

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Formal Accident Investigation Process

• Establish investigation team ASAP
• Brief survey of information available (on site if
  possible)
• Set objectives and delegate responsibilities
• Preincident facts gathered and organized
• Accident facts gathered and organized including
  detail examinations and photos
• Research and analyses to clarify perplexing
  evidence
• Report

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• Formal Accident Investigation Report
• Introduction
• Process description (equipment and chemistry)
• Incident description
• Investigation results
• Discussion
• Conclusions
• Layered recommendations

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• Accident Investigation Summary
• Complete formal accident investigation reports
  are detailed and not as useful for the average
  inquirer. Recently the Investigation Summary,
  a one to two page summary, has been used to
  spread information

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• Case Histories
• Case histories are written descriptions of
  accidents, including the causes, consequences,
  and methods required to prevent similar events.
  They are written by the personnel with the
  hands-on experience the ones who know and
  appreciate the accident and accident prevention
  methods

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• Case Histories
• One learns from history or is doomed to repeat
  it
• Especially true for safety anyone working in the
  chemical industry can learn from case histories
  and avoid hazardous situations or ignore history
  and be involved in potentially life threatening
  accidents

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• Forensic Engineering
• The chapter contains several interesting tidbits
  to reconstruct what happened in an accident.
• Burning rates for wood
• Effects on metal at different T
• Pressure rise with deflagration
• Pressure rise with detonation
• Bursting pressures
• Eq. 12-4, 12-5 Cylindrical
• Eq. 12-6, 12-7 Spherical

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• Vessel Failure
• Can work in either direction

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• Group Presentation
• Two or three groups give presentation each day
• Can use chalk board, models, PowerPoint,
  overheads, etc.
• If using PowerPoint, must have it preloaded and
  ready to run.
• Please hurry to class. We are on a tight
  schedule and need to start ASAP or earlier!

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• Group Presentation
• Plan on a 12 minute presentation with some
  questions at the end
• Must be prepared to answer question (audience
  must be prepared to ask questions)
• All group members must participate
• Grading given as group
• Rest of class will give a written evaluation of
  presentation
• Participation as an evaluator is graded

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Group Presentations

• Since I need to be out of town on Monday, April
  30, we will NOT have presentations that day. You
  can use the day to study for other classes or
  prepare you presentation.
• On Wednesday we will have only two presentations
  to allow us time to work the bugs out. After
  that, there will be three groups present each day.

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