Above ground testing of wood preservatives - some experiences from Sweden

IRG/WP 95-20079

B Henningsson, Ö Bergman

Field stake tests for the evaluation of wood preservatives have been used for more than 50 years in Sweden. In the Nordic countries a system for approval of wood preservatives, which includes field test, has also been in operation for more than 25 years. This system has been described in an IRG Document by Henningson & Jermer (1988). The Nordic system is now in a process of harmonization with the European system based on CEN's hazard classes (Henningsson & Jermer, 1994). Strangely enough, field testing for approval purposes in Sweden and the Nordic countries has only been done with stakes in soil contact. In earlier days approval requirements for a preservative for above ground situations was determined on the basis of results obtained in stake tests. Subsequently the Nordic approval system accepted laboratory decay tests as an approval basis for above ground preservatives. The European Standard EN 113 or comparable methods were allowed. This means that wood preservatives for above ground use could be approved after only laboratory tests, which - as a matter of fact - was against the generally accepted testing philosophy in these countries. The absence of standardised methods for field testing of above ground preservatives, however, does not necessarily mean that such tests have not been performed in Sweden. In the following some examples of above ground testing will be given. Although these tests may not particularly have been designed for testing the efficacy of wood preservatives, they may be of interest in discussing methodology and they may be imptortant in special cases. The examples are: Test with plank pieces; Window-frame corners; Organotin degradation test; tests with piled samples; tests about the natural durability of wood panels.


Conference: 95-05-11/16 Helsingør; Denmark

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