This part of the EN 20 series specifies a method for the determination of the protective effectiveness or the toxic values of a wood preservative against infection by Lyctus brunneus (Stephens) in wood which has been treated previously by full impregantion.This method is applicable to:- water-insoluble chemicals which are being studied as active insecticides; or- organic formulsation, as supplied or as prepared in the laboratory by dilution of concentrates.This method is applicable to water-based preservatives.NOTE This method can be used in conjuction with ageing procedures, which do not remove the added nutrient.