Study on the correlation of lab assay and field test for fouling-release coatings

In this paper, two organisms, diatom and Ulva spore, were employed to evaluate the antifouling performance of five fouling-release (FR) coatings in laboratory, and field test was also assessed. The correlation of lab assay and field test was studied using Spearman's rank correlation test. The results show that the Spearman's coefficient (r_s) between lab assay and field static test is 0.975 (p = 0.005) for diatom and 0.949 (p = 0.014) for Ulva spore respectively, which are significant at the 95% probability level. This indicates that the lab static assays using diatom and Ulva spore have good agreement with field static test. For dynamic performance evaluation, the r_s between diatoms adhesion assay and field dynamic test is 0.894 (p = 0.041) while the r_s for Ulva spore is 0.289 (p = 0.638), indicating the lab dynamic assay with diatom is accordance with the field dynamic test. Therefore, diatom was used to evaluate the performance of coating materials which exhibits the satisfactory correlation and consistency between lab assessment and field test, confirming that diatom is an adapted evaluation organism to evaluate FR coatings.