EN 599的这一部分规定了EN 335-1中定义的五种使用类别中的每一种，用于评估木材防腐剂用于预防固体木材的功效所需的生物试验以及相应使用所需的最小老化试验类。它提供了计算防腐剂临界值的方法。临界值是用于计算适用于特定使用条件的防腐剂的推荐保留值的值。临界值不一定是防腐剂的推荐保留值或最小保留值。欧洲范围内广泛的危害，暴露条件和使用寿命要求，有必要在计算所需防腐剂保留时考虑当地的考虑; EN 351-1规定了要考虑这些因素的临界值进行调整。 EN 599的这一部分适用于以液体形式供应的所有木材防腐产品，用于预防木材攻击真菌，木材攻击昆虫和海洋钻孔的木材（结构和非结构）的处理，如EN 335- 1。但是，适用于对真菌造成损伤的预防性处理用产品

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.