ABSTRACT

Offshore exploration and shipping activity related to mining in northern territories are now really active, though these areas are concerned by harsh weather conditions. The offshore structures are subjected to atmospheric and marine icing phenomenon where heavy ice accumulations may increase the danger for workers and may cause failure in apparatus, detectors and safety devices. Several thermal and mechanical de-icing methods exist for some parts of the structure; however the use of efficient icephobic coating could reduce energy consumption and improve the safety level of workers. But, the question remains: how do we assess the performance of the icephobic coating? Moreover, what is the level of icephobicity needed to claim it achieves its role? To answer these interrogations, a complete in-lab evaluation procedure of the coatings performance subjected to offshore harsh winter conditions is suggested. The evaluation method consists of two steps, firstly ice adhesion tests, under both atmospheric icing and, sea water icing, and re-evaluation after numerous icing-de-icing cycles and UV degradation. The second step consists of ice accumulation tests, under sea spray icing and interaction spray icing. In order to validate this evaluation procedure, a silicone-based icephobic coating has been evaluated. Results show significant reductions in ice adhesion, by comparison in centrifuge adhesion testing, and accumulation, by compared to the mass on bare metal samples. A chart has been introduced to present concise results allowing a fair comparison between different coatings, in order to select the best. Several other parameters can also be used to evaluate the effectiveness of the icephobic, such as the effect of cold temperature, effect of corrosion, rain erosion, sand erosion and even its effect on environment. Finally, testing has been carried out to demonstrate an ice self-shedding of a coating under offshore conditions.

INTRODUCTION

Ice adhesion and accumulation on metal structures subjected to winter conditions is a highly important safety issue for offshore exploration and shipping encountered in cold Arctic regions. The added weight of ice accumulation on buildings can cause structural defects, which could create a hazard for on-site workers during de-icing operations and maintenance jobs (J. L. Laforte, M. A. Allaire, & J. Laflamme, 1998; Ryerson, 2008). To help solve those issues, efficient de-icing methods have been developed, although they consume a great deal of energy and/or necessitate elaborate infrastructure and maintenance (J.-L. Laforte, M.-A. Allaire, & J. Laflamme, 1998).

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