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Best practices for cutting and removing pipes in the splash zone

The harsh conditions in the splash zone make pipe-cutting and removal projects complex. The operation carries safety risks, requires careful planning to preserve the installation’s structural integrity, and is subject to stringent regulatory requirements. Pipe-cutting projects are also time-sensitive, with delays potentially resulting in significant financial losses. 

Addressing these challenges requires a combination of experience, expertise, and meticulous planning. At OceanTech, our team of senior engineers has executed remotely operated splash zone projects since 2007. We perform cutting and removal operations on flowlines, risers, caissons, guides, braces, and brackets, and we can also perform similar tasks for the offshore wind and fish farming industries. Using our robotic solutions enables our engineering team to perform any type of repair work at offshore installations. Here are our best practices for cutting and removing pipes in the splash zone.

Choosing the right equipment and techniques

Various cutting methods are available for pipes, including mechanical cutting, thermal cutting, and abrasive cutting. It is advisable to consider accessibility, environmental factors, the pipe material, dimensions, and the pipe’s condition when choosing your method. Inspecting the installation in advance allows you to determine the pipe’s integrity and identify potential weak points. This will help you select the appropriate method.

At OceanTech, we commonly use diamond wire saws (DWS) that allow for precise and controlled cutting. These saws also reduce the amount of debris generated during the cutting process, minimising environmental impact. While certain offshore operations can employ remotely operated underwater vehicles (ROVs), the conditions in the splash zone require other equipment and techniques. Using our robotic solution for vertical cutting means we can mount diamond wire saws on vertical access tools fixed to structures. This enables improved accuracy and control in hard-to-reach areas.

The equipment required for pipe removal encompasses lifting frames, cranes, winches, or ROVs with lifting capabilities. Regardless of your chosen equipment, it should be capable of operating effectively in offshore conditions and be equipped to minimise the generation of debris and contaminants. At our Subsea Test Center in Trondheim, we test methods, equipment, and tools before deploying them offshore. This practice enables us to tailor the solution to the unique requirements of each project.

Environmental considerations

The splash zone is a unique and ecologically sensitive area where marine and terrestrial environments converge. It harbours diverse ecosystems, and disrupting this balance can have significant ecological consequences. Prior to project execution, it is crucial to assess the environmental impact of the cutting process and take measures to minimise it. 

This includes: 

  • Using environmentally friendly methods
  • Ensuring proper disposal of waste materials to comply with environmental regulations
  • Implementing containment measures to prevent debris from dispersing. For example, you may deploy debris collection systems, such as nets or screens, to capture loose particles from the cutting process.

Using support vessels is another factor to take into consideration. Reducing your reliance on support vessels allows you to mitigate emissions, minimise the risk of spills, and prevent waste discharges that introduce pollutants into the water. Our splash zone projects do not need support vessels. We control our operations from a purpose-built control unit on the topside of the installation. 

Risk assessments and safety measures

Before initiating pipe-cutting operations offshore, it is highly recommended to conduct a thorough risk assessment that encompasses potential hazards and corresponding mitigation strategies. 

You should assess factors such as: 

  • Wave action
  • Currents
  • Underwater visibility
  • Potential underwater hazards
  • Presence of flammable substances
  • High pressures
  • Confined spaces
  • The pipes’ structural integrity

Prioritise safety at all times. Adhere to company safety policies and regulatory bodies’ relevant safety regulations, guidelines, and protocols. OceanTech’s technology enables unmanned operations in close proximity to structures and within confined spaces. Our robotic solutions empower remote work, significantly reducing the requirement for human operators to physically enter the splash zone. This approach effectively mitigates the risk of injury associated with exposure to perilous conditions like wave action and strong currents.

Effective communication and collaborative planning

When project stakeholders prioritise effective communication and foster a culture of teamwork, they enhance coordination and cooperation. Although OceanTech’s offshore teams are typically compact, often comprising two to seven engineers, our onshore operations boast a multitude of support teams. These are responsible for diverse tasks and functions, including HSE, quality assurance, logistics, design, data modelling, strategic planning, and technical support at our Subsea Test Center. We also collaborate with partners such as Vertikal Service AS, who provide us with rope access technicians and riggers on larger projects.

The wide range of teams and stakeholders in pipe-cutting projects requires clear communication and collaborative planning to ensure everyone understands their roles and responsibilities. Collaborative planning allows all stakeholders to contribute their expertise and insights, identifying potential project risks and hazards. It also ensures that all tasks are properly coordinated, minimising conflicts and maximising efficiency by addressing potential bottlenecks before execution offshore. Cutting and removing pipes in the splash zone requires precision to avoid damaging other structures or equipment. Collaborative planning allows for multi-disciplinary discussions on techniques, tools, and equipment.

Please note that our best practices are general recommendations. It is crucial to adhere to industry-specific regulations and guidelines and to consult with local regulatory bodies for specific requirements for your business.