Lessons Learned From Accidents Involving Maintenance Procedures

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Lessons Learned From Accidents Involving
Maintenance Procedures
Institute for the Protection and Security of the
Citizen
J. Sales, EC-JRC-MAHB
Ispra - 31 January 2007
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Maintenance Accidents

• Involve all type of process industry activities
• Wide variety of scenarios (fire, release,
  explosion)
• Linked to other areas of process safety
• Contractors
• Process analysis
• Inspections
• Existing guidelines available
• Should be implemented in SMS

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Maintenance Guidelines

• Literature review from different sources previous
  to accident analysis.
• Maintenance management.
• Companies should include maintenance in their
  Safety Management procedures.
• Preventive maintenance.
• Measures to anticipate possible equipment
  failure must be put in place.
• Operating procedures.
• Any activity related to maintenance and cleaning
  must be clearly documented.
• Safety analysis of operations must be provided in
  order to identify possible hazards.

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Maintenance Accidents Analysis (I)
Pipe cracked due to corrosion

• 2 main categories
• Preventive maintenance
• Insufficient / inadequate
• Management, process analysis
• Inspection
• Maintenance operations
• Process analysis
• Working procedures
• Training supervision

Wrong cleaning
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Maintenance Accidents Analysis (II)

• 99 Accidents involving maintenance identified
• 59 related to preventive maintenance
• 40 related to maintenance operations
• 32 accidents reported fatalities 74 fatalities
• Severity of consequences
• Preventive maintenance 14 (24) accidents
  reported fatalities, with 37 fatalities total
• Maintenance operations 18 (45) accidents
  reported fatalities, with 37 fatalities total
• Operators present
• Hazards unexpected / operators unprepared

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Lessons Learned Management System

• Management involves technical and organisational
  aspects of maintenance.
• Implementation of an appropriate safety culture.
• Involvement of all the staff with
  responsibilities in maintenance tasks.
• Appropriate communication between personnel.
• Specific training programs for maintenance
  (external workers).
• Supervision of maintenance operations.
• Identification and documentation of equipment and
  plant sections that require maintenance.
• Written procedures with clear, detailed and well
  structured instructions for maintenance
  activities.
• Establishment of safety analysis for maintenance
  operations and scheduling of preventive
  maintenance.

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Lessons Learned Process Analysis (I)

• Preventive maintenance schedules must be
  established according to plant and equipment
  characteristics.
• Periodic inspection and testing for all equipment
  (valves, isolation, joints, welds, etc.).
• Calibration programs for sensors, control and
  alarm systems.
• Lubrication of joints and other systems (e.g.
  rotary equipment).
• Replacement of materials at the end of
  life-cycle.
• Hazard analysis of the relevant operations
  related to maintenance.
• Evaluate the possible consequences of an accident
  taking place during maintenance and cleaning
  procedures.

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Lessons Learned Process Analysis (II)

• Corrosion, erosion or fatigue of construction
  materials must be taken into consideration during
  process analysis.
• Variation of expected life-cycle of plant
  equipment.
• Coatings and anticorrosive paints must be
  provided
• Compatibility of cleaning substances to be used
  must be studied in order to avoid unexpected
  chemical reactions.
• Flammable conditions have to be studied where use
  of devices that may act as ignition sources must
  be studied (e.g. welding works).
• Reliability of testing procedures must be
  ensured.
• Process conditions not to alter plant or
  equipment set-up.

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Example 1

• A pipe section was provided with protective paint
  to avoid corrosion.
• Hot water was passed through the pipe for
  cleaning.
• This procedure removed the protective paint so
  the pipe became vulnerable to corrosion.
• Eventually the pipe cracked.
• A better process analysis was needed.

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Lessons Learned Training and Operating Procedures

• Effective training programs must be provided for
  maintenance
• Operators must know and understand the hazards
  involved in any operation before starting
  maintenance operations (chemical hazards).
• Contract workers must be involved in specific
  training programs.
• Revision in order to avoid overconfidence.
• Work permits must be used strictly.
• Detailed procedures to carry out activities
  safely.
• Specifications of the hazards involved.
• Establishment of responsibilities.
• Description of correct plant situation before
  starting maintenance activities (correct valve
  positions documented, disconnection of control
  systems, etc.) Procedures for shut-down
  start-up (disconnection of alarms).
• Effective supervision for maintenance operations
  must be provided.

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Example 2

• Maintenance operations in a vessel containing
  TiCl4.
• Control system not disconnected.
• On disconnecting the signal wiring of the level
  measurement device the process computer responded
  to this signal as empty and opened the control
  valve to fill the vessel.
• Vessel overflow releasing TiCl4.
• TiCl4 produces HCl ant TiO2 on contact with water
  (including air humidity).
• Thick white cloud of HCl was generated inside the
  building.
• As a result, two operators died.

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Lessons Learned Equipment, Control And Emergency
Systems (I)

• Appropriate equipment must be provided according
  to the specific task (and hazards identified) to
  be performed.
• Use of inert gas for purging installations when
  flammability hazards may be present.
• Control systems must be linked with the
  activation of safety measures and alarm systems.
• Alarm systems must be clearly designed to
  eliminate confusion in case of an emergency.
• All workers should be able to identify and
  recognise different alarm signals at any zone of
  the establishment.

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Example 3

• Maintenance work to be performed inside a vessel.
• Vessel contained flammable liquid had been
  emptied.
• Flammable vapour remained inside the tank.
• Operators used a halogen lamp inside the tank.
• A spark from the lamp ignited the vapours killing
  2 operators.

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Lessons Learned Equipment, Control And Emergency
Systems (II)

• Evacuation routes must be indicated before
  starting any activity and easy to follow in case
  of an emergency.
• Personnel protective equipment must be provided.
  This equipment must be in accordance with the
  type of activity to be developed (e.g. absence of
  pockets to avoid introducing foreign objects).
  Also, rules for operators should be provided
  regarding outfit (absence of watches, jewellery,
  and so on).

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Conclusions

• Maintenance accidents are still happening with
  severe consequences even though there are
  published guidelines on the topic.
• Lessons learned provided in MARS cases are quite
  generic when it comes to maintenance issues.
• Efforts must be set on
• Management implication.
• Training and Supervision.
• Hazard analysis of operations.
• Work permits.
• Preventive maintenance.
• Response systems.