STUDY OF THE EXPIRATION DATE OF FIRE-PROTECTIVE COATING (IMPREGNATION) OF FIRE-PROTECTIVE AGENTS FOR WOOD

Abstract

The problematic issues of determining the term of preservation of the effectiveness of fire protection of wood treated with impregnating by fire-retardants and coatings are considered. Indicated main guiding documents that set the requirements for quality of fire protection agents and fire protected wood, also methods of their testing, including the determination of the shelf life of fire-retardant coating or impregnation. According to the results of previous research and publications, it has been established that for some types of fire protected coatings decreasing in their flame-retardant efficiency significantly outstrips the appearance of external signs of coating destruction, and the actual expiration date of some fire protected coatings is shorter than expected. The main climatic factors that affect the change of fire protection efficiency of fire protected wood during its operation are indicated. The method of conducting field experimental studies to determine the expiration date of fire protection coating and impregnations, as well as the method of determining the group of fire protection effectiveness of fire-retardant agents are described. The existing groups of fire protection efficiency of fire-retardant agents and admissible values of weight loss of samples during fire tests according to ГОСТ 16363-98 depending on group are resulted. The general view of the installation for determining the group of fire protection efficiency of coatings and impregnating substances for wood is shown. Intermediate results of research on determining the expiration date of some fire protection coatings and impregnations on samples of wood, stored for two years in heated and unheated rooms are presented. According to the results of experimental studies, it is established that the loss of flame retardant efficiency of samples of fire-retardant wood stored in unheated and heated rooms, depending on the time of their storage, is slowly increasing. A more noticeable increase in weight loss, due to greater fluctuations in temperature and humidity, is observed for samples stored in unheated rooms. Minor changes in weight loss were recorded for samples with fire-retardant coatings, which are more resistant to changes in atmospheric factors than samples that are flame-retardant based on water-soluble substances. Especially quickly lose their fire-retardant properties of wood samples impregnated with the method of surface impregnation with "ББ-32", which is classified as easily washable.