Gå til hovedinnhold

Audit of technical safety and maintenance management on Skarv FPSO

The Petroleum Safety Authority (PSA) carried out an audit of the technical safety and maintenance management disciplines on Skarv FPSO during the period 4-6 June 2010. The audit activity identified several non-conformities in relation to regulatory requirements.

The audit focused on technical conditions on board the facility as well as certain systems used by BP to ensure that the selected solutions are in compliance with the petroleum regulations.

The audit activities aimed at the disciplines in question were carried out at the Samsung construction yard in South Korea, where project personnel were interviewed, verifications were performed on board the facility and technical documentation was reviewed.

A start-up meeting was also held in BP's offices at Forus on 8 April 2010 as well as a clarification meeting that was part of the audit activities in BP's project organisation in Oslo on 25 May 2010.

The audit is linked to the future Application for Consent for use of the facility on the Norwegian shelf. It has been decided that this facility will not be issued an Acknowledgement of Compliance from the PSA. Experience from corresponding audits of other FPSO facilities fabricated at foreign shipyards has shown that it may be challenging to safeguard understanding and implementation of regulations within the selected disciplines.

The objective of the audit activities was to verify that management and technical issues on the facility, within the selected discipline areas, were safeguarded in accordance with regulatory requirements throughout the engineering and construction phase. The company's own governing documents and studies/analyses were also taken into account during the verifications.

The audit activities identified several non-conformities within the areas covered by the audit. These are items that must be remedied before the facility may be used on the Norwegian shelf.

Examples of such items include:

  • Observation of several mechanical connections on the riser side of the emergency shutdown valves.
  • Implementation of the emergency shutdown system in a manner that does not comply with regulatory requirements, in particular as regards control of electrical ignition sources.
  • Deficient preservation of some equipment and components. The PSA is very concerned about such issues, as they may have an impact on safety and the working environment during the start-up and operations phase, as well as result in higher maintenance costs in the future.

Some documents have been submitted to the PSA after the summary meeting at the construction site, most recently via an e-mail on 26 May 2010. These were not reviewed before the report was issued.

The PSA's observations are generally divided into two categories:

  • Non-conformities: This category is for observations, that in the opinion of the PSA, indicate lack of compliance with regulatory requirements.
  • Improvement items: Used for observations of deficiencies, but where the information is insufficient to prove a lack of compliance with regulatory requirements.


Mechanical connections before the first emergency shutdown valve
Several flanges were fitted on the pipe connections between dynamic risers and the first emergency shutdown valve.

The following requirement is stipulated in Section 58, third subsection of the Facilities Regulations relating to pipeline systems: with regard to flexible pipeline systems and pipeline systems made of a material other than steel, usage factors and, if applicable, load and material factors shall be determined so as to ensure that the safety level for such systems is not lower than that of pipelines and risers made of steel. The PSA's interpretation of this requirement is that if solutions other than steel pipelines and steel risers are selected, analyses and evaluations must be performed to demonstrate that the selected solution is at least as good or better than a more traditional solution based on steel risers. When steel risers are used, it has also become established practice to use a welded joint between the riser and the emergency shutdown valve. Thus, the use of a weld is to be regarded as part of the solution when steel risers are used. Correspondingly, flanged joints must be subjected to an evaluation if use of such connections is considered rather than a welded connection.

In Section 4, litera b of the Facilities Regulations, cf. Section 9 of the Framework Regulations, it is stipulated that facilities shall be designed in such a manner that the major accident risk becomes as low as practically possible. The requirement that the risk shall be reduced to become as low as practically possible is to be understood as an assumption that all other regulatory requirements are complied with.

It is also stated in the guidelines to Section 9 of the Framework Regulations that one cannot use analyses or calculations of risk in order to avoid having to comply with other requirements stipulated in the regulations: The requirement of this provision as to risk reduction entails that the established minimum level for health, environment and safety must be complied with without regard to costs and that the party responsible cannot set aside specific requirements of the health, environment and safety legislation with reference to calculation of risk.

Reference is also made to Section 18, third subsection of the Framework Regulations: When other solutions than those recommended in the guidelines to a provision of the regulations are used, the party responsible shall be able to document that the chosen solution fulfils the requirements of the regulations. Combinations of parts of standards shall be avoided, unless the party responsible is able to document that an equivalent level of health, working environment and safety is achieved.

During the meeting on 25 May BP stated that it has qualified safety equivalence between the Techloc clamp flange installed in the turret area and the compact flange recommended in NORSOK.

Ignition source control
The emergency shutdown system is implemented in a manner that does not comply with the requirements related to control of electrical sources of ignition in the event of hydrocarbon leaks.

Maintaining the installation's heading in relation to the wind, as well as in serious situations, is defined as a critical functionality by BP. This function requires that the facility's machinery for operation of propellers is running. The power requirements of this machinery are so great that it necessitates operation of the facility's main power generators (dual fuel units) and essential generators for as long as possible, including in situations where gas is detected in safe (unclassified) areas (see SKA-AK-S-SA-1018, rev D2). This means that a large portion of the facility's electrical installations will be operative. It was stated in the meeting on 25 May 2010 that about 90 per cent of the 11 kV switchboards will be live in such a situation.

A central element in a strategy to reduce risk related to ignition of hydrocarbons is to reduce the number of ignition sources to the extent feasible in practical terms, both by avoiding potential sources of ignition in classified areas, and not least by implementing a philosophy for disconnection of ignition sources that reduces the risk to become as low as practically possible in the event of a hydrocarbon leak.

Interviews in Korea as well as during the meeting on 25 May 2010 showed that relevant project personnel, including operations personnel, understood and described the function for disconnection of ignition sources differently. Some parties acknowledged that manual interventions would be necessary as part of the process to ensure sources of ignition were disconnected, while others described an automatic function.

It was also not possible to present a philosophy that clearly stated how the ignition source control should be implemented in order to ensure regulatory requirements were complied with. Section 32 of the Facilities Regulations relating to emergency shutdown systems stipulates that the command structure shall be simple and unambiguous.

Deficient preservation of equipment and components


  • The preservation work was inadequate in several locations. It was noted that equipment such as valves, instruments, electrical panels and electrical junction boxes were not preserved or covered in an adequate manner. Equipment was exposed to dust from grinding/ welding and other activities or was exposed to penetration of water in open areas on the facility.
  • BP's own preservation procedure was not complied with, as some preserved equipment was not marked, some marking was inadequate, etc.
  • Preservation that had been completed was broken and/or damaged.
  • Valve and pipe flange connections were not protected in several locations with risk of damage to seal surfaces on flanges and/or valve bodies. Valve stems, valves and pipes were not adequately protected, in addition to electrical junction boxes not being preserved with silica gel, for example, or left with open cable ports.
  • Random testing showed that it could not be documented that the ”Preservation Punch List” had been updated and entered in the ”Mechanical Completion Punch List Register” or MIPS.

Improvement items

The IOPPS system is designed in such a manner that a fault in common components may disable all or parts of both the PSD and IOPPS systems.

Skarv FPSO has overpressure scenarios where the capacity of the PSVs is not sufficient to protect the first and second stage separators as well as the test separator against overpressure. BP has therefore installed a secondary instrumented overpressure protection system, IOPPS, to prevent overpressure in these scenarios. The IOPPS system operates the riser valve and the associated shutoff valve upstream of the manifold and choke. The PSA has been informed that the IOPPS system is to be independent of the PSD system with the exception of the shutoff valve and the associated actuator.

This is also reflected in the design documentation submitted to the PSA. However, in connection with the verification on board Skarv FPSO, the PSA observed that both IOPPS and PSD are dependent upon a common hydraulic control valve. This means that if this valve fails, both systems may be disabled.

It is also appears uncertain to the PSA whether this has been taken into consideration in the fault tree analysis performed to ensure that the acceptance criteria for separator overpressure have been safeguarded.

NORSOK P-001 allows for use of an instrumented safety system as both primary and secondary barriers in three defined situations. The situation on Skarv FPSO, where the PSV capacity is insufficient to prevent overpressure from one flow line alone, is not included among these.

A lack of compliance with requirements stipulated in standards referred to in the regulations may generally be handled internally if the safety level stipulated in the regulations is maintained. In this case, this means that the IOPPS solution must be handled as a non-conformity internally even if the acceptance criterion for overpressure is safeguarded.

Deficient marking
Deficient marking of equipment


  • Deficient marking and use of different marking systems were observed on board the facility. Some of the marking systems were also of variable quality.
  • It was noted that several different internal company procedures were used for marking of equipment (Samsung, SBM and BP-Skarv)
  • Some tags were fastened in a manner that rendered them nearly impossible to read
  • Some tags had been covered by paint and were difficult to read
  • Faulty coding was observed in some cases

The opportunity to train personnel who will operate the facility by direct participation in the project work should be utilised better
BP has several employees of the Skarv operations organisation on location in South Korea. It was stated by several of them that BP does not make good enough use of the opportunity to let them become familiar with the facility.


  • The opportunity for ’on the job training’ for the operations and maintenance personnel was prevented by unnecessary limitations on their ability to take part in the work on the facility (commissioning).
  • Lack of equipment, such as one extra operator station, placed unnecessary limitations on their opportunity to familiarise themselves with the process facility and the control and safety system.

Other comments and questions

  • During the meeting in Oslo on 25 May 2010, BP stated that it has verified safety equivalence (for relevant scenarios) between the Techloc flange and the compact flange (NORSOK). The PSA will evaluate whether to conduct a third party verification of this study.
  • SBM has specified that both API 6FA and BS 6755 can be used concerning the fire resistance of ESDVs. The PSA would like documentation that demonstrates that these specifications are equal and which one has been selected.
  • Necessary certificates for the hoisting pulley could not be presented.
  • The essential generator put into operation did not have a maintenance log or maintenance requirements/programme from the supplier.