6 Wood Discoloration

7.4 Protection 149
preservatives. In Europe, the standards are ruled by the European Committee
for Standardization (Table 7.6; Willeitner 2005b).
Figure 7.5 shows a Kolle flask that is used according to the European standard
EN 113 to determine the toxic values of wood preservatives against wooddestroying
Basidiomycetes cultured on agar medium. The method can be also
used to test the natural durability of timber species etc.
Chemical wood preservation is used, if structural-constructive measures, or
natural durability, or wood modifications alone are insufficient for an increased
wood endangering to meet the requirement of long-term use of wood. Not
durable wood species or those of insufficient durability and the sapwood
of all wood species can be made resistant for a long time against damage
by treatment with appropriate wood preservatives, provided that the wood
shows permeability. Prerequisite is, corresponding to the wood use, to bring
effective formulations in sufficient amount deeply into the wood (Schoknecht
and Bergmann 2000) using appropriate methods (Willeitner and Schwab 1981;
Table 7.6. European standards that deal with resistance and preservation of wood against
fungi
EN 335 (1992/95) Durability of wood and wood-based products; Definition of
hazard classes of biological attack (3 parts)
EN 350 (1994, 2 parts), EN 460 (1994) Durability of wood and wood-based products –
Naturaldurabilityofsolidwood
ENV 12038 (1996) Durability of wood and wood-based products – Wood-based panels
ENV 12404 (1997) Durability of wood and wood-based products – Assessment of the
effectiveness of a masonry fungicide to prevent growth into wood of Dry rot Serpula
lacrymans (Schumacher ex Fries) F.S. Grey
EN 113 (1996) Determination of toxic values of wood preservatives against wood
destroying Basidiomycetes cultured on agar medium
EN 152 (1989) Test methods for wood preservatives; Laboratory method for
determining the protective effectiveness of a preservative treatment against blue
stain in service (2 parts)
EN 252 (1990) Field test method for determining the relative protective effectiveness of
a wood preservative in ground contact
EN 330 (1993) Wood preservatives; Field test for determining the relative protective
effectiveness of a wood preservative for use under a coating and exposed out of
ground contact: L-joint method
ENV (prestandard) 807 (2001) Wood preservatives – Determination of the effectiveness
against soft rotting micro-fungi and other soil-inhabiting micro-organisms
ENV 839 (2002) Wood preservatives – Determination of the effectiveness against wood
destroying Basidiomycetes – Application by surface treatment
ENV 12037 (1996) Wood preservatives – Field test method for determining the relative
protective effectiveness of a wood preservative exposed out of ground contact
www.taq.ir