ÖNORM EN 599-1

This part of EN 599 specifies for each of the five use classes defined in EN 335-1, the biological tests required for evaluating the efficacy of wood preservatives for the preventive treatment of solid timber, together with the minimum ageing tests required for the respective use class. It provides the method for calculating the critical value of a preservative. The critical value is the value that shall be used to calculate the recommended retention of the preservative appropriate for specific service conditions. The critical value is not necessarily the recommended retention or the minimum retention level for the preservative. The wide range of hazards, exposure conditions and service life requirements across Europe make it necessary to allow for local considerations in the calculation of the required preservative retention; EN 351-1 provides for the critical value to be adjusted to take account of these factors. This part of EN 599 is applicable to all wood preservative products supplied for application in liquid form for the preventive treatment of timbers (structural and non-structural) against wood-attacking fungi, wood-attacking insects and marine borers as described in EN 335-1. However, it is applicable to products for preventive treatments against fungi causing disfigurement (blue stain) of wood in service if this forms part of the overall preventive efficacy of the product. This part of EN 599 does not necessarily take into account all the factors which may affect the stability of active ingredients in preservative treated wood. These factors include ultra-violet light and microbiological agencies capable of degrading components of the preservative. Such factors are an integral part of exposure in field trials but are subject to natural variation and their impact is not directly assessed in the field trial methods included in this standard. Methods are in development to assess the impact of these factors but are not finalised and cannot be included in this revision of this part of EN 599. Because such factors could, in service, significantly affect the active ingredient´s suitability for its intended purpose, the manufacturer/ producer is expected to ensure and be able to provide evidence that its stability, at the recommended retention of the preservative product, has been adequately assessed. This part of EN 599 is not applicable to wood preservative products supplied for application as pastes, solids or in capsule or gaseous form because these cannot be tested without modification of the biological tests cited in this standard. It does not apply either to wood preservative products for remedial (curative) treatments, to those applied to prevent fungi causing sap stain on green (unseasoned) timber or to those applied solely to prevent fungi causing disfigurement (blue stain) of wood in service.