The Status of the Warren Spring Laboratory's Rolling Flask Test

This paper discusses the use of dispersants in the United Kingdom and describes the work undertaken to improve the laboratory test for the assessment of oil spill dispersant efficiency together with some of the supporting ongoing work in the field of dispersant evaluation. The revolving flask test used to measure the efficiency of oil spill dispersants was originally developed by Petrofina Ltd., but has been modified to meet the requirements of a simple test procedure to select dispersants for use at sea in accordance with the regulatory requirements of the U.K. Ministry of Agriculture, Fisheries and Food. Test results depended on operator technique and equipment. A program involving manufacturers, oil companies, and users was undertaken to improve the technique and precision of the test. Reproducibility between laboratories was on the order of ±10% mean. The test has been correlated with spraying trials at sea in which a carpet of oil was sprayed with a commercially available dispersant and the amount of oil dispersed into the sea by wave action was visually assessed.