Identifying compatible waterborne timber preservatives and fire retardants for use in a VPI system: a practical approach

Abstract

To enhance the use and suitability of timber in all applications in both exterior and interior settings, timber typically needs to be treated with a preservative and/or a fire retardant chemical. Combining fire retardants with preservatives into a single treatment process has been a long-term aim of researchers in the timber preservative industry because of the significant logistic and economic advantages. This trial explored combining commercially available timber treatment preservatives and fire retardants in a pilot trial to target either H3 (outdoor, above ground) and BAL29 (fire performance) or H2F (internal framing) and Group 1 (fire performance). These combined samples were assessed for stability and feasibility for use in either a vacuum pressure facility or a spray application for the treatment of timber. Of the sixty fire retardant and preservative combinations, a total of twenty-two combinations recorded satisfactory (or better) performance. Each fire retardant product was compatible with two or more common preservatives. These results, coupled with further research, could significantly change the treatment process in Australia and improve the performance and longevity of timber in bushfires, grassfires and internal applications.