ABS issues notation for wind turbine installation unitsPublications // May 4, 2010
With the emergence of mobile offshore units primarily intended for the installation, maintenance and repair of wind turbines, leading offshore classification society ABS announced during the Offshore Technology Conference in Houston this week that it has issued a new notation for these specialized units, Wind IMR.
Wind turbine installation, maintenance and repair (IMR) units are a distinct type of offshore unit for the renewable energy sector combining existing technologies in novel ways. These units typically include large accommodations, a helideck, dynamic positioning (DPS-2) and are fitted with large high capacity cranes. The work decks are constructed to support and stow large wind turbine components for transport.
“These specialized units need to distinguish themselves within the offshore industry with a distinct classification notation,” said Michael Sano, ABS Senior Engineer, Energy Project Development. “We have developed this notation with a specific set of standards. No doubt these standards will evolve over time as we keep pace with developments in the offshore wind industry.”
The notation, with its class requirement standards, is included in a new chapter within the ABS Guide for Building and Classing Mobile Offshore Units. Chapter 7, Specific Unit Types, details requirements for the wind turbine IMR units including pile driving, tower installation, nacelle and blade installation, supporting structure for pile driving equipment and supporting structure for deck cargo.
Sano said deck cargo requirements also take into account other items which are installed in association with a wind power generation structure. It also includes any temporary structures such as racks, stands or cradles which are not permanently attached to the unit.
He added that any crane permanently installed on board an ABS-classed wind IMR unit and intended for operations other than supply of provisions and maintenance of the unit is to be certified by ABS in accordance with Chapter 2 of the ABS Guide for the Certification of Lifting Appliances or API Specification 2C.
ABS has seen an increase in offshore support vessel activity aimed at the renewable energy market and has been involved with the classification of jackup barges, multipurpose offshore construction vessels (OCVs) and self-elevating units (SEUs) all capable of offshore wind turbine installations. Now specialized mobile offshore units that meet the newly developed requirements from ABS will receive the Wind IMR notation.