Adhesives for load-bearing timber structures - Test methods - Part 3: Determination of the effect of acid damage to wood fibres by temperature and humidity cycling on the transverse tensile strength
This part of EN 302 specifies a method for determining the effect on bond strength of damage to wood fibres caused by the action of acids from the adhesive during climatic cycling.
It is suitable for the following applications:
a) assessing the compliance of adhesives with EN 301;
b) for assessing the suitability and quality of adhesives for load-bearing timber structures;
c) for determining if the adhesive after bonding has a damaging influence on the strength of the wood due to chemical action.
This test is intended primarily to obtain performance data for the classification of adhesives for load-bearing timber structures according to their suitability for use in defined climatic environments. This test is carried out on spruce (Picea abies L.).
This method is intended for use to provide numerical design data and does not necessarily represent the performance of the bonded member in service. It is not intended to be used to assess the suitability of adhesives for the manufacture of wood-based panels.
NOTE Attention is drawn to the fact that the performance requirement established in EN 301 for the acid fibre damage test applies only if either:
1) the adhesive mixture, or
2) one of the adhesive components, when applied separately,
shows a pH value lower than 4,0, as determined by EN 1245.