Corrosion of hollow section members on offshore drilling structures
IMCA’s attention has been brought to instances of potentially serious corrosion on certain types of derricks on jack-up offshore drilling rigs. During the periodical inspection of drilling structures, a significant structural integrity issue has been identified. The derricks affected are mostly all 1.2-1.3m hook load or GNC derricks built in the early 1980s.
The issue discovered is advanced corrosion of load bearing members within hollow section members on certain models of drilling derrick. This corrosion on the derrick members has been shown to be serious enough to affect the performance and therefore the load bearing capacity of these derricks. In the worst case scenario, there is the potential for member failure which could in turn overload other structural members or create a significant structural failure and/or DROPS incident.
Further information can be found at derricksl.com/casestudy-detail.aspx?-corrosion-of-hollow-section-members-on-offshore-drilling–structures
Corrosion-related failure of materials as an immediate cause of near misses or even actual incidents is something that has come to the attention of IMCA on a number of occasions recently. members may wish to look into this, particularly where corrosion may be hidden, difficult to access or otherwise likely to be overlooked.
Safety Event
Published: 27 June 2016
Download: 
IMCA SF 16/16
IMCA Safety Flashes
Submit a Report
IMCA Safety Flashes summarise key safety matters and incidents, allowing lessons to be more easily learnt for the benefit of all. The effectiveness of the IMCA Safety Flash system depends on Members sharing information and so avoiding repeat incidents. Please consider adding safetyreports@imca-int.com to your internal distribution list for safety alerts or manually submitting information on incidents you consider may be relevant. All information is anonymised or sanitised, as appropriate.
IMCA’s store terms and conditions (https://www.imca-int.com/legal-notices/terms/) apply to all downloads from IMCA’s website, including this document.
IMCA makes every effort to ensure the accuracy and reliability of the data contained in the documents it publishes, but IMCA shall not be liable for any guidance and/or recommendation and/or statement herein contained. The information contained in this document does not fulfil or replace any individual’s or Member's legal, regulatory or other duties or obligations in respect of their operations. Individuals and Members remain solely responsible for the safe, lawful and proper conduct of their operations.