ISO 21318:2007规定了一种测定水萃取物导电性的方法，该水萃取物是在95°C下用水萃取环氧树脂而获得的。该方法仅适用于在萃取温度（95°C）下处于熔融状态的环氧树脂。 该方法对用作电子设备绝缘材料的环氧树脂非常重要。萃取物的导电性用作测量树脂中离子种类的浓度。

ISO 21318:2007 specifies a method for the determination of the electrical conductivity of an aqueous extract obtained by extraction of an epoxy resin with water at 95 °C. The method is applicable only to epoxy resins that are in the molten state at the extraction temperature (95 °C). The method is important for epoxy resins which are used as insulation materials for electronic devices. The electrical conductivity of the extract is used as a measure of the concentration of the ionic species in the resin.