This part of EN 20 specifies a method for the determination of the protective effectiveness or the toxic values of a wood preservative against infestation by Lyctus brunneus (Stephens) when the product is applied as a surface treatment to wood. This method is applicable to: - Water-insoluble chemicals which are being studied as active insecticides, or, - Organic formulations, as supplied or as prepared in the laboratory by dilution of concentrates, or, - Organic water-dispersible formulations as supplied or as prepared in the laboratory by dilution of concentrates, or - Water-soluble materials e.g salts