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Piper Alpha Oil rig explosion (Event Sequence (Around 12pm on the 6th of…

- - - - Design flaw - Did not shut down when emergency stop button was pressed on platform Piper
  - - - Safety valve
        
        Active failure - Workers didn't put the safety valve back on, by the original deadline of 6pm (Maritime Executive 2018)
      - Disk Cover
        
        Design flaw - latent failure- Disk cover could leak if sealed only by hand and that when it is sealed by hand it looks like it was sealed with a wrench (Maritime Executive 2018)
        
        Active failure - Workers only hand tightened the metal disk cover (Maritime Executive 2018)
        
        Failed Barrier defeated by the above active failure - Used as part of safety procedures to prevent leakage whilst maintenance is going on
      - Design flaw - Latent failure - The ability of the pump to start without the safety valve
    - - Design flaw - Condensate pump often stopped working/had to be restarted (Feed Your Need, 2017)
    - - Emergency stop button
      - Gas alarms
      - Loudspeakers
      - Design flaw - Latent failure - Room used for gas compression was right next to the control room (Maritime Executive 2018)
    - - Blockage occurred due to accumulation of methane caltrate
    - - Design flaw - latent error - Grating on the floor was sharp (Feed Your Need, 2017)
        
        Active failure - Divers put rubber mats over grating (Feed Your Need, 2017)
    - - Design flaw - Latent failure - Designed to withstand fire not explosions (Maritime Executive 2018)
  - - - Evidence of safety procedures as there were work permits
      - No/little supervision/ double checking
    - - Manager of Piper platform - accountable for production meeting schedule
        
        Put pressure on him to get production restarted after Pump B's failure, lead to decision to start Pump A
- - - - Fireproofed Staff Accommodation block
        
        Was put directly underneath the helicopter deck, so workers could access helicopters in times of emergency
    - - Designed for fire
    - - Module D - For the generation of power (Feed Your Need, 2017)
      - Module C - Processing Oil & Gas (Feed Your Need, 2017)
      - Module B - Processing Oil & Gas (Feed Your Need, 2017)
      - Module A - Oil piped up from the bottom of the sea (Feed Your Need, 2017)
      - Modules originally designed so that dangerous operations were away from accommodation
        
        Conversion from oil to gas processing changed this - as this safety concept was no longer adhered to
        
        Lead to gas processing being next to control room
    - - Production deck contained: control room + four modules (Feed Your Need, 2017)
      - Above production deck - Deck containing accommodation as well as entertainment (Feed Your Need, 2017)
  - - - Cost a large amount
        
        Due to transport costs
        
        Materials having to be strong enough to support other structures + plant/equipment + workers + withstand the sea
    - - Feedback
        
        Gas alarms gave control room operators both visual and sound feedback
      - Decals
  - - - SWMS
      - Safety procedures
      - Emergency drills/training
      - Hand over procedures
      - Control room procedures
  - - - Gas alarms
      - Permits to work (PTW) (Feed Your Need, 2017)
      - Firewalls
      - PPE
    - - Manager under pressure for platform to run 24/7
    - - All maintenance must have a permit
    - - Made many safety designs such as firewalls, redundant
      - Original designers did not design the platform with this in mind
  - - - Constant repairs due to scale of operation
      - condensator pumps routinely failed assumption/expectiation (Feed Your Need, 2017)
  - - - 1970s oil crisis occurred during this time - so there was a rush to create these platforms (Baxter, 2017)
      - Design flaw - Designers built the platforms to last but gave little thought to how they would be decommissioned (Baxter, 2017)
- - - - Goals - Goals were to meet production targets and ensure that the Piper platform was running as much as possible
        
        His goals as well as the expectations placed on him and his own expectations, are what caused him to make the active failure of starting Condensate Pump A
      - Knowledge - Condensate Pump B often stopped working, so it wasn't alarming
      - Expectations
        
        Higher ups expected no unnecessary shut downs of production
        
        Expected Condensate Pump A to be fine to be started as no permits to state otherwise (Maritime Executive 2018)
      - Stress - Was extremely stressed as he had to get a condensate Pump restarted within a few minutes or else all power would be lost
    - - Expectations - Expected not to cease oil extraction without permission from Occidental Control centre
        
        Latent failure - Manager had to wait for permission even in emergency scenario ,shows that the system is not resilient
    - - Expectations
        
        Was expected to listen to his superiors
        
        Lead to the gas pipeline between platform Tartan and Piper, to continue to be pumped with gas even after first explosion - As it was an instruction from his superiors - Active failure (Maritime Executive 2018)
      - Goals
        
        To make his superiors happy
        
        Caused him to make the above active failure
  - - - Not attempts at cross platform communication
      - Day shift engineer did not tell night shift custodian about missing safety valve on condensate pump A - Active failure Information Transfer - Bad handover (Maritime Executive 2018)
      - No one was informed of where the permit for Pump A's maintenance was - Active failure Information Transfer - Bad handover (Maritime Executive 2018)
      - No one was informed of Pump A missing its safety valve - Active failure Information Transfer - Bad handover (Maritime Executive 2018)
- - - - Site Design - Precondition - Divers walked around this area barefoot and the sharp grating hurt their feet (Feed Your Need, 2017)
        
        Site design - Active failure - Divers put down rubber mats which covered the holes in the grating - lead to crude oil puddle fire as drops of oil accumulated, that melted and ruptured the gas line connecting Piper to platform Tartan (Feed Your Need, 2017)
  - - - Equipment design - Precondition - Maintenance of condensate Pump A led to its safety valve having to be removed
        
        Equipment design - Active failure - Workers only hand tightened the disk cover for condensate Pump A
      - Equipment design - Latent failure - Disk cover could leak if sealed only by hand and that when it is sealed by hand it looks like it was sealed with a wrench
  - - - Work Environment - Visibility - Precondition - Workers not knowing whether condensate Pump A's safety valve is on or not
        
        Work Environment - Visibility - Active failure - Condensate Pump A being started without its safety valve being on (Maritime Executive 2018)