Improvement of reaction to fire performance of birch plywood by veneer soaking method

This research paper presents a study on improving the reaction to fire performance of birch plywood. Birch plywood finds wide application in various industries, particularly in construction, where it is used for decorative panelling, structural purposes, and panels with acoustic properties. However, one obstacle to the standard use of plywood in these applications is its reaction to fire performance. In many countries, fire safety regulations require plywood products to comply with B-s1,d0 class standards. The objective of this research was to elevate the natural reaction to fire performance level of birch plywood from D-s1,d0 to B-s1,d0 class, as per EN 13501-1:2018 standards. To achieve this goal, were investigated the highest level of fire protection technology available. The approach involved fire impregnation technology, wherein each individual veneer was soaked in two different fire-retardant solutions before gluing. Two soaking technologies were explored, with veneers being dried in industrial veneer dryers after impregnation. Plywood samples were produced at an experimental scale using laboratory press but adhered fully to industrial-scale gluing technology. The reaction to fire performance was evaluated using the single burning item test method prescribed by EN 13823:2020, which is the primary method for assessing reaction to fire performance according to EN 13501-1:2018 standard. The research yielded a potential fire protection technology capable of achieving B-s1,d0 compliant birch plywood. Both dry veneer soaking and wet veneer soaking technologies showed promise in achieving the desired reaction to fire performance. However, several technological aspects, such as the type of fire retardant, liquid concentration level, temperature, and the soaking time, need to be fine-tuned for optimal results.