This part of ISO 15181 specifies a general method for extracting biocides from antifouling paint films into artificial seawater under specified laboratory conditions. It is used in conjunction with the other parts of ISO 15181 to determine the amounts of specific biocides in the extract, for example copper and/or certain organic biocides, and to enable the release rate of those biocides from the paint film under the specified laboratory conditions to be calculated.