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Audit of management of major accident risk and handling of barriers – Transocean

During the period of 1-4 November 2010, the Petroleum Safety Authority Norway (PSA) carried out an audit of Transocean Offshore Ltd’s (Transocean’s) management of major accident risk and handling of barriers.

The audit activity was started with an all-day meeting with the management on land on 21 October 2010, and was followed up with verification on board the Transocean Leader facility from 1-4 November 2010.

In the start-up meeting on land, the PSA was given a review of the Transocean management’s understanding of strategies and principles that form the basis for the design, use, and maintenance of barriers. The management’s roles and the measures designed to ensure understanding of risks as regards major accidents, was presented.

Transocean is in the process of implementing a ”Bow-tie” methodology (bow-tie diagrams) that illustrate hazardous situations and probability-reducing barriers on one side, and consequence-reducing barriers following incidents on the other side.

On the Transocean Leader facility, the PSA verified Transocean’s management and knowledge of major accident risk by reviewing two major accident scenarios in the form of ”table-top” exercises related to the facility’s defined hazard and accident situations.

Furthermore, the verification was carried out through interviews, a review of the emergency preparedness plan and other documentation. Risk factors associated with well activities, fire and explosion hazard and handling of preparedness after serious incidents, were prioritised.

An inspection was also carried out on the facility. The entire emergency response organisation participated in an exercise focused on training for a major accident scenario. A meeting with the safety delegate service was also held.

The audit activity was well-organised by Transocean.

The audit activity was connected to two of the PSA’s main priorities for 2010:
• ”Management and major accident risk”, with the goal that management at all levels of the industry must work to reduce major accident risk, and ensure that this work is carried out in a comprehensive manner.
• ”Technical and operational barriers”, with the goal that technical and operational barriers are safeguarded in a comprehensive and consistent manner, so that the risk of major accidents is reduced as much as possible.

Transocean Leader is a semi-submersible drilling facility built in 1986. Transocean received an Acknowledgement of Compliance (AoC) for the facility in 2004.

The purpose of the audit activity was to evaluate the company’s understanding, knowledge and competence as regards major accident risk and barrier mindset, on the part of both management and employees. Furthermore, we wanted to evaluate strategies and principles for management, design, use and maintenance of barriers – particularly with regard to major accident scenarios.

Transocean’s main management has defined which DFUs can primarily trigger major accidents. Currently there is not a complete overview of the appurtenant operational and organisational barrier systems, and the company lacks a systematic approach in the area.

The implementation of the ”bow-tie” methodology is intended to maintain and visualise the connection between hazardous situations and barriers. The PSA views the methodology as a useful tool that has a good potential for practical application through further development in the company. The methodology has recently been introduced, and has not yet been prepared for all major accident scenarios.

The PSA found little familiarity with the bow-tie methodology and little knowledge of how this methodology was supposed to be used among the personnel on board Transocean Leader. The PSA found varying degrees of knowledge and understanding of which DFUs have major accident potential. It was not clear to the audit team that training and exercises focused on major accident risk were awarded special attention.

Six nonconformities and eight improvement items were identified during the audit.

Management of major accident risk

  • Nonconformity: Major accidents – follow-up of barriers and performance requirements
    Comprehensive strategies and principles were not established for the design, use and maintenance of barriers.
  • Nonconformity: Maintenance management and barrier follow-up
    The RMS maintenance system was the planned tool for testing and verification of the quality of technical barriers designed to prevent major accidents. The system was, however, lacking and not updated to handle this function.
  • Improvement item: Emergency preparedness plan – Defined hazard and accident situations (DFU)
    The DFUs were inadequate, and did not describe all relevant hazardous situations.
  • Improvement item: Upgrading the drill floor area
    The equipment and design of the drill floor and in the derrick was not optimal.
  • Improvement item: Fire fighting fire using fixed CO2 extinguishing systems. CO2 fire extinguishing systems were installed in many rooms to fight larger fires in the room. Such a system is not considered a fast and effective fire extinguishing system.
  • Improvement item: The company’s master management system and local adjustments
    Some directives from the company’s main office are not well-adapted to local conditions.

Other factors

  • Nonconformity: Fire hoses
    Some fire hoses were not in accordance with the requirements.
  • Nonconformity: Battery emergency lighting
    Inadequate battery emergency lighting in rooms for Co2 bottles
  • Nonconformity: Training and exercises
    Inadequate training plan and logging of fire team training.
  • Nonconformity: Storage and access to rescue equipment
    Unsuitable design of changing area and storage of fire-fighter and MOB boat crew equipment.
  • Improvement item: Deploying anchor lines after highest ESD level
    It was unclear which measures were implemented to avoid a risk of ignition in connection with deployment of anchor lines in an emergency situation.
  • Improvement item: Communication equipment for smoke divers
    Unsuitable communication equipment.
  • Improvement item: Escape routes
    Inadequate marking of escape routes.
  • Improvement item: Information flow in the safety delegate service
    Inadequate information flow between management and the safety delegate service offshore and between the safety delegate service offshore and on land.