Five key UXO considerations for successful offshore projects

The roadmap to ALARP

The starting point for marine developments must be a comprehensive UXO risk assessment with a robust risk mitigation strategy. The strategy provides a roadmap to a safe construction site and ALARP sign-off, a certificate confirming the UXO risk is ‘as low as reasonably practicable’. The ALARP certificate is the end goal, so do your research from the outset. Is the certificate insured? How long is it valid for? Are there exclusion zones? Only partner with a company capable of fulfilling ALARP obligations.

Schedule management

Marine developments are major investments on a tight schedule. The UXO survey informs the quantity, type, and location of potential targets across the site, but the survey findings may disrupt the schedule, leading to time and cost overrun. For example, a survey that identifies 1500 UXO targets will require three times more vessel days than a survey that identifies 500 targets – particularly challenging if this happens at the end of the summer season. However, a robust risk mitigation strategy can help anticipate setbacks for swift resolution, allowing the project to get back on track. Fugro optimises operations by running survey and identification vessels simultaneously, informed by real-time data that is processed remotely. This approach is suited to weather-critical operations and maximises uptime during the summer months.

False positives

Fugro’s UXO mantra is ‘better survey for less identification’. Up to 99 % of targets dredged out following a survey are false positives: mostly ocean debris such as anchors and chains. That inefficiency is why Fugro has invested in research and development to minimise false positives requiring a ‘dig’. We apply 3D imaging technology to investigate magnetic anomalies and support the dredge/no-dredge decision. We have used it on approximately 2000 UXO targets to date and achieved a 75 % reduction in false positives, saving time and money.

Detection and identification methodologies

UXO detection and identification methodologies often rely on oil and gas technology unsuited to today’s offshore wind industry – but we’re changing that. For nearshore operations, where UXOs are buried deep below strong currents, we’ve developed an innovative identification solution: a diverless shallow-water tool integrating sensors, cameras, an optimised dredge and more. We have eight remote operations centres that supervise ROVs and receive live data; through remote operations, we’ve moved many of our project teams onshore to reduce offshore exposure. Fugro’s ROVs will soon be capable of dredging out and identifying UXO targets entirely remotely, which will be a game-changer in terms of safety, cost, time, and carbon emissions.

Risk mitigation strategy

The construction of an offshore wind farm (OWF) involves many elements, from export cables to foundations and jacket. Some OWF developments have multiple UXO risk mitigation strategies and use different survey and identification contractors, but this approach fails to leverage economies of scale. Instead, choose a single provider for your UXO risk mitigation strategy, covering the entire OWF site, to benefit from an all-encompassing set of standards and procedures, one ALARP validity and a single mobilisation fee.

In conclusion…

If you’re an offshore developer, initiate your UXO risk assessment and mitigation strategy at the earliest possible opportunity and choose your UXO risk mitigation provider wisely. Select one which has a strong track record, robust processes, and can optimise their survey and identification techniques to improve safety while reducing time and costs. Above all, ensure your provider sets a clear roadmap to ALARP and can fulfil their obligations, should the project take an unexpected turn.

Learn more about Fugro's UXO risk mitigation solution:

Fugro provides a complete solution for unexploded ordnance risk mitigation on marine development projects. Through a predictable and optimised process, your project will benefit from on-time delivery of the ALARP certificate, the highest safety standards, innovative solutions and operational excellence.

Did you know?

• The marine environment is home to an estimated 1.3 million tonnes of UXO

• If you extracted all the UXO devices in the marine environment and placed them end to end, the line of munition would stretch from Amsterdam to Hong Kong

• 95 % of potential targets listed during a typical UXO survey turn out to be false positives