In the paper I authored for the RINA International Journal of Maritime Engineering (IJME), I set out to explain the real challenges and considerations involved in carrying out major tank coating refurbishment projects on operational, on-station floating assets like FPSOs (Floating Production Storage and Offloading units) and FSUs (Floating Storage Units). This blog provides a summary of some of the key points made in that technical paper.
From my experience in the field, it’s clear that these kinds of coating jobs are inevitable as these assets age, and the original protective coatings start to break down. What makes the situation particularly complex is that these refurbishments often need to happen while the vessel remains offshore and in production.
The first step in tackling these projects is thorough planning and preparation. Defining the scope early on is vital. Knowing which areas truly need attention can avoid unnecessary work in zones where coatings are still sound. This can reduce the amount of access scaffolding, blasting, and painting needed, which also improves safety. Choosing the right coating system is equally important. Modern epoxy-based coatings, including solvent-free and surface-tolerant varieties, can make a big difference depending on the tank’s condition and environmental challenges. In some cases, it’s more sensible to deviate from the original shipyard coating spec and opt for newer, more practical solutions.
It’s also important to understand the constraints of each asset: space for equipment, hatch sizes, crane reach, and so on. Tank structures themselves can be highly complex, with stiffeners that collect debris and make access difficult. Planning for proper access, rescue routes, and even additional hatches might be necessary.
Creating a safe working environment is perhaps the most critical element. Confined space entry is inherently dangerous, and when you’re doing this in tanks beneath live oil and gas processing equipment, the risks multiply. Ventilation needs to be carefully engineered. Clean, gas-free air must be drawn from safe zones and monitored continuously. Should a topside hydrocarbon release occur, the ventilation system must shut down immediately to avoid drawing dangerous gases into the tank. Preventing ingress of fluids, such as rainwater or spilled hydrocarbons, is another major concern during these long-duration entries. Proper lighting, including emergency lighting, must also be in place.
Surface preparation is a key contributor to the success of any coating project. Freshwater washing removes contaminants and salt before blasting begins, and dehumidification helps to maintain a stable tank atmosphere. It is common to use either dry or slurry blasting depending on conditions – each has its pros and cons. Selecting recyclable blasting media is vital given the space and disposal limits on floating assets. Over the last few years we’ve also seen gains using robotic blasting tools like remote crawlers, which reduce confined space entry requirements, working-at-height requirements, scaffolding requirements, whilst also improving productivity during blasting operations.
Once surfaces are prepared, quality assurance must be performed on the surfaces before moving to coating application. Stripe coating – applying paint by hand to edges, welds, and corners, helps strengthen the coating system to these vulnerable areas. The full coats are then applied, typically using airless spraying. Again, it’s important to ensure that the environment supports the application. Controlling humidity, checking for contaminants, and managing paint vapour safely through careful ventilation.
To wrap up, treating tank coating refurbishment as a major engineering project, rather than just routine maintenance, is crucial. With the right planning, technology, and attention to safety, it’s entirely possible to carry out these works to a high standard while the asset remains on-station and in production. Doing so not only maintains safety and integrity but can also help avoid far more costly steel renewals in the future.