Houlder was contracted by marine oil and gas combustion system suppliers, John Zink Hamworthy Combustion Engineering to develop and verify the structural design of an open sided boiler module structure. The structure was to securely house two super heated, high pressure boilers and associated equipment on the deck of an FPSO (Floating Production, Storage and Offloading) vessel.

The FPSO vessel has an operating and design life minimum of 10 years and is moored through a forward turret. This allows the vessel to stay on station, weathervaning around the turret securely in up to 78m water depth.  The Boiler Module is designed to operate within the FPSO’s Zone 2 hazardous area, exposed to harsh environment and vessel motions. The boiler module structure primarily comprises pancake grillage interfaced with the vessel support structure and topside structures providing access to the boilers and economisers, burners and other equipment.

A full detailed design package, comprising structural verification, fatigue and buckling calculations and reports, was prepared by the Houlder design and engineering team for Classification Society approval. A complete package of Scantling Design drawings was also produced in AutoCAD design software.  The calculations and drawings were to a sufficient level of detail to allow the client’s chosen fabricator to procure materials and develop their work packages prior to work commencing.

The boiler module structure was designed to comply with Lloyd’s Register (LR) Floating Offshore Installation at a Fixed Location Rules and Regulations 2008. It was fabricated in Singapore with all the primary equipment installed, loaded onto and seafastened to a vessel for transportation to Hamburg for installation.

The module weight, at lift and installation onto the FPSO vessel support structure, was approximately 812 tonnes. After installation the FPSO was transferred to the Tyne for final commissioning and hook up of the service supplies and pipe supports.