The main deck of a floating production storage and offloading (FPSO) vessel is exposed to harsh environmental conditions, which can cause corrosion and deterioration of the steel structure. In order to maintain the integrity of the vessel, the corroded main deck plating will require to be renewed when the thickness is below the requirements of the classification’s societies.

The main deck is the area where the topside process modules are located. These modules handle and process the oil and gas produced from the subsea wells. Flammables gas can leak or spill from the process equipment, piping, valves, or storage tanks due to corrosion, fatigue, impact, or human error.

The Need for Alternative Deck Reinstatement Solutions

Renewal of steel plating normally require hot work, such as welding or cutting. This can create fire or explosion hazards, especially if there are flammable materials or gases nearby. Doing hot work on FPSO main deck can require extensive preparation, installation, and inspection time. Hot work can also disrupt the normal operation of the FPSO, which can affect its production capacity and revenue.

The requirement of doing hot work on FPSO main deck can also require more labour and material. A possible alternative is to use cold repair methods, such as Sandwich Plate System (SPS), which can eliminate the need for hot work and offer several benefits over conventional techniques.

Introducing the Sandwich Plate System (SPS)

Sandwich Plate System (SPS) is a structural composite material that consists of two metal plates bonded with a solid elastomer core. SPS was developed by SPS Technology, the world’s leading supplier of structural composite solutions to the offshore and maritime industries.

SPS is a mature proven cold repair technology in the maritime market. It was invented by Dr Stephen Kennedy following primary research in the field of ice-strengthened structures at Carleton University in Ottawa, Ontario, Canada and first patented in 1996. The first recorded project involving SPS was carried out on the P&O Pride of Cherbourg, a Lloyd’s Register approved vessel in 1999. Therefore, SPS has been in the market for about 25 years. The first cold work application was carried out in 2003 for Conoco Phillips FPSO Independences.

Advantages of SPS Cold Work Solutions

SPS cold work solutions offer several advantages over traditional hot work methods for FPSO Main Deck Reinstatement. Some of these advantages are:

  • Safety

    SPS cold work solutions eliminate the need for hot work in hazardous environments, such as those involving flammable cargo, materials, or gases. This reduces the risk of fire, explosion, or injury to personnel and the environment.

    The requirements of confine space entry is eliminated with SPS Cold Work solutions as all cold repair works are carried out on the main deck without any entries to the tank below.

  • Time

    SPS cold work solutions require less preparation, installation, and inspection time than conventional methods. SPS can be installed in parallel with other activities, without disrupting the normal operation of the FPSO. SPS also eliminates the need of tank cleaning, which can be costly and time-consuming.

    Normally, all SPS face plates and perimeter bar are all fabricated in the workshop on shore. It has reduced the schedule of the process on board.

  • Cost

    SPS cold work solutions require less labour and material than conventional methods. SPS can save up to 90% of labour and 56% of steel compared to crop and renew techniques. SPS can also reduce the maintenance and operational costs of the FPSO by extending its service life and enhancing its performance.

    The requirement of POB (Persons on Board) is greatly reduced as the majority of the fabrication works are done on shore.

  • Quality

    SPS cold work solutions provide a permanent, durable, and class-approved repair that restores or improves the structural integrity of the FPSO. SPS can also provide superior protection against corrosion, fatigue, impact, and blast.

    cold repair for deck reinstatement                                                      SPS Application on Deck. Credits: SPS Technology

Therefore, SPS cold work solutions can provide a safe, fast, cost-effective, and high-quality alternative for FPSO main deck reinstatement. SPS is approved by all major classification societies and has been used in over 500 projects worldwide.

SPS: A Promising Cold Repair Solution

Sandwich Plate System (SPS) composite repair for FPSO is promising, as the technology is evolving and gaining acceptance in the offshore industry. The cold repair technology is constantly improving to meet the challenges and demands of the offshore industry. New methods, and products are being developed to enhance the performance, durability, and reliability of composite repair solutions.

The cold repair technology is subject to various standards and regulations from different authorities and organisations. These standards and regulations aim to ensure the safety, quality, and consistency of composite repair solutions. All majority IACS Classifications Societies has published Rules/Guides for Composite Repairs. Some of the professional bodies like AMPP and API has started to recognise the potential benefits of the composite repairs.